2015-09-22 20:47:10 +08:00
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/*
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* System Trace Module (STM) infrastructure
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* Copyright (c) 2014, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* STM class implements generic infrastructure for System Trace Module devices
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* as defined in MIPI STPv2 specification.
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*/
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#include <linux/uaccess.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/compat.h>
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#include <linux/kdev_t.h>
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#include <linux/srcu.h>
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#include <linux/slab.h>
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#include <linux/stm.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include "stm.h"
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#include <uapi/linux/stm.h>
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static unsigned int stm_core_up;
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/*
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* The SRCU here makes sure that STM device doesn't disappear from under a
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* stm_source_write() caller, which may want to have as little overhead as
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* possible.
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*/
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static struct srcu_struct stm_source_srcu;
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static ssize_t masters_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct stm_device *stm = to_stm_device(dev);
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int ret;
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ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end);
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return ret;
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}
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static DEVICE_ATTR_RO(masters);
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static ssize_t channels_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct stm_device *stm = to_stm_device(dev);
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int ret;
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ret = sprintf(buf, "%u\n", stm->data->sw_nchannels);
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return ret;
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}
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static DEVICE_ATTR_RO(channels);
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static struct attribute *stm_attrs[] = {
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&dev_attr_masters.attr,
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&dev_attr_channels.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(stm);
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static struct class stm_class = {
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.name = "stm",
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.dev_groups = stm_groups,
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};
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static int stm_dev_match(struct device *dev, const void *data)
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{
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const char *name = data;
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return sysfs_streq(name, dev_name(dev));
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}
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/**
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* stm_find_device() - find stm device by name
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* @buf: character buffer containing the name
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*
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* This is called when either policy gets assigned to an stm device or an
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* stm_source device gets linked to an stm device.
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*
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* This grabs device's reference (get_device()) and module reference, both
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* of which the calling path needs to make sure to drop with stm_put_device().
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*
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* Return: stm device pointer or null if lookup failed.
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*/
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struct stm_device *stm_find_device(const char *buf)
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{
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struct stm_device *stm;
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struct device *dev;
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if (!stm_core_up)
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return NULL;
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dev = class_find_device(&stm_class, NULL, buf, stm_dev_match);
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if (!dev)
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return NULL;
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stm = to_stm_device(dev);
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if (!try_module_get(stm->owner)) {
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put_device(dev);
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return NULL;
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}
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return stm;
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}
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/**
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* stm_put_device() - drop references on the stm device
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* @stm: stm device, previously acquired by stm_find_device()
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*
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* This drops the module reference and device reference taken by
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* stm_find_device().
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*/
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void stm_put_device(struct stm_device *stm)
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{
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module_put(stm->owner);
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put_device(&stm->dev);
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}
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/*
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* Internally we only care about software-writable masters here, that is the
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* ones in the range [stm_data->sw_start..stm_data..sw_end], however we need
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* original master numbers to be visible externally, since they are the ones
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* that will appear in the STP stream. Thus, the internal bookkeeping uses
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* $master - stm_data->sw_start to reference master descriptors and such.
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*/
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#define __stm_master(_s, _m) \
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((_s)->masters[(_m) - (_s)->data->sw_start])
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static inline struct stp_master *
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stm_master(struct stm_device *stm, unsigned int idx)
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{
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if (idx < stm->data->sw_start || idx > stm->data->sw_end)
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return NULL;
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return __stm_master(stm, idx);
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}
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static int stp_master_alloc(struct stm_device *stm, unsigned int idx)
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{
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struct stp_master *master;
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size_t size;
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size = ALIGN(stm->data->sw_nchannels, 8) / 8;
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size += sizeof(struct stp_master);
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master = kzalloc(size, GFP_ATOMIC);
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if (!master)
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return -ENOMEM;
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master->nr_free = stm->data->sw_nchannels;
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__stm_master(stm, idx) = master;
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return 0;
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}
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static void stp_master_free(struct stm_device *stm, unsigned int idx)
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{
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struct stp_master *master = stm_master(stm, idx);
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if (!master)
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return;
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__stm_master(stm, idx) = NULL;
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kfree(master);
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}
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static void stm_output_claim(struct stm_device *stm, struct stm_output *output)
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{
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struct stp_master *master = stm_master(stm, output->master);
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if (WARN_ON_ONCE(master->nr_free < output->nr_chans))
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return;
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bitmap_allocate_region(&master->chan_map[0], output->channel,
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ilog2(output->nr_chans));
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master->nr_free -= output->nr_chans;
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}
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static void
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stm_output_disclaim(struct stm_device *stm, struct stm_output *output)
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{
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struct stp_master *master = stm_master(stm, output->master);
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bitmap_release_region(&master->chan_map[0], output->channel,
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ilog2(output->nr_chans));
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output->nr_chans = 0;
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master->nr_free += output->nr_chans;
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}
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/*
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* This is like bitmap_find_free_region(), except it can ignore @start bits
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* at the beginning.
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*/
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static int find_free_channels(unsigned long *bitmap, unsigned int start,
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unsigned int end, unsigned int width)
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{
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unsigned int pos;
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int i;
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for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) {
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pos = find_next_zero_bit(bitmap, end + 1, pos);
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if (pos + width > end + 1)
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break;
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if (pos & (width - 1))
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continue;
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for (i = 1; i < width && !test_bit(pos + i, bitmap); i++)
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;
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if (i == width)
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return pos;
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}
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return -1;
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}
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static unsigned int
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stm_find_master_chan(struct stm_device *stm, unsigned int width,
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unsigned int *mstart, unsigned int mend,
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unsigned int *cstart, unsigned int cend)
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{
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struct stp_master *master;
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unsigned int midx;
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int pos, err;
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for (midx = *mstart; midx <= mend; midx++) {
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if (!stm_master(stm, midx)) {
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err = stp_master_alloc(stm, midx);
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if (err)
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return err;
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}
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master = stm_master(stm, midx);
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if (!master->nr_free)
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continue;
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pos = find_free_channels(master->chan_map, *cstart, cend,
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width);
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if (pos < 0)
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continue;
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*mstart = midx;
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*cstart = pos;
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return 0;
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}
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return -ENOSPC;
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}
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static int stm_output_assign(struct stm_device *stm, unsigned int width,
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struct stp_policy_node *policy_node,
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struct stm_output *output)
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{
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unsigned int midx, cidx, mend, cend;
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int ret = -EINVAL;
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if (width > stm->data->sw_nchannels)
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return -EINVAL;
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if (policy_node) {
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stp_policy_node_get_ranges(policy_node,
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&midx, &mend, &cidx, &cend);
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} else {
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midx = stm->data->sw_start;
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cidx = 0;
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mend = stm->data->sw_end;
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cend = stm->data->sw_nchannels - 1;
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}
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spin_lock(&stm->mc_lock);
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/* output is already assigned -- shouldn't happen */
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if (WARN_ON_ONCE(output->nr_chans))
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goto unlock;
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ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend);
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if (ret)
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goto unlock;
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output->master = midx;
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output->channel = cidx;
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output->nr_chans = width;
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stm_output_claim(stm, output);
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dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width);
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ret = 0;
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unlock:
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spin_unlock(&stm->mc_lock);
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return ret;
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}
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static void stm_output_free(struct stm_device *stm, struct stm_output *output)
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{
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spin_lock(&stm->mc_lock);
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if (output->nr_chans)
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stm_output_disclaim(stm, output);
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spin_unlock(&stm->mc_lock);
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}
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static int major_match(struct device *dev, const void *data)
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{
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unsigned int major = *(unsigned int *)data;
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return MAJOR(dev->devt) == major;
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}
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static int stm_char_open(struct inode *inode, struct file *file)
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{
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struct stm_file *stmf;
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struct device *dev;
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unsigned int major = imajor(inode);
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int err = -ENODEV;
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dev = class_find_device(&stm_class, NULL, &major, major_match);
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if (!dev)
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return -ENODEV;
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stmf = kzalloc(sizeof(*stmf), GFP_KERNEL);
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if (!stmf)
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return -ENOMEM;
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stmf->stm = to_stm_device(dev);
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if (!try_module_get(stmf->stm->owner))
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goto err_free;
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file->private_data = stmf;
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return nonseekable_open(inode, file);
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err_free:
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kfree(stmf);
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return err;
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}
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static int stm_char_release(struct inode *inode, struct file *file)
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{
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struct stm_file *stmf = file->private_data;
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stm_output_free(stmf->stm, &stmf->output);
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stm_put_device(stmf->stm);
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kfree(stmf);
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return 0;
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}
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static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width)
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{
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struct stm_device *stm = stmf->stm;
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int ret;
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stmf->policy_node = stp_policy_node_lookup(stm, id);
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ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output);
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if (stmf->policy_node)
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stp_policy_node_put(stmf->policy_node);
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return ret;
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}
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static void stm_write(struct stm_data *data, unsigned int master,
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unsigned int channel, const char *buf, size_t count)
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{
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unsigned int flags = STP_PACKET_TIMESTAMPED;
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const unsigned char *p = buf, nil = 0;
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size_t pos;
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ssize_t sz;
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for (pos = 0, p = buf; count > pos; pos += sz, p += sz) {
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sz = min_t(unsigned int, count - pos, 8);
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|
|
sz = data->packet(data, master, channel, STP_PACKET_DATA, flags,
|
|
|
|
sz, p);
|
|
|
|
flags = 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil);
|
|
|
|
}
|
|
|
|
|
|
|
|
static ssize_t stm_char_write(struct file *file, const char __user *buf,
|
|
|
|
size_t count, loff_t *ppos)
|
|
|
|
{
|
|
|
|
struct stm_file *stmf = file->private_data;
|
|
|
|
struct stm_device *stm = stmf->stm;
|
|
|
|
char *kbuf;
|
|
|
|
int err;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* if no m/c have been assigned to this writer up to this
|
|
|
|
* point, use "default" policy entry
|
|
|
|
*/
|
|
|
|
if (!stmf->output.nr_chans) {
|
|
|
|
err = stm_file_assign(stmf, "default", 1);
|
|
|
|
/*
|
|
|
|
* EBUSY means that somebody else just assigned this
|
|
|
|
* output, which is just fine for write()
|
|
|
|
*/
|
|
|
|
if (err && err != -EBUSY)
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
kbuf = kmalloc(count + 1, GFP_KERNEL);
|
|
|
|
if (!kbuf)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
err = copy_from_user(kbuf, buf, count);
|
|
|
|
if (err) {
|
|
|
|
kfree(kbuf);
|
|
|
|
return -EFAULT;
|
|
|
|
}
|
|
|
|
|
|
|
|
stm_write(stm->data, stmf->output.master, stmf->output.channel, kbuf,
|
|
|
|
count);
|
|
|
|
|
|
|
|
kfree(kbuf);
|
|
|
|
|
|
|
|
return count;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int stm_char_mmap(struct file *file, struct vm_area_struct *vma)
|
|
|
|
{
|
|
|
|
struct stm_file *stmf = file->private_data;
|
|
|
|
struct stm_device *stm = stmf->stm;
|
|
|
|
unsigned long size, phys;
|
|
|
|
|
|
|
|
if (!stm->data->mmio_addr)
|
|
|
|
return -EOPNOTSUPP;
|
|
|
|
|
|
|
|
if (vma->vm_pgoff)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
size = vma->vm_end - vma->vm_start;
|
|
|
|
|
|
|
|
if (stmf->output.nr_chans * stm->data->sw_mmiosz != size)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
phys = stm->data->mmio_addr(stm->data, stmf->output.master,
|
|
|
|
stmf->output.channel,
|
|
|
|
stmf->output.nr_chans);
|
|
|
|
|
|
|
|
if (!phys)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
|
|
|
|
vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
|
|
|
|
vm_iomap_memory(vma, phys, size);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg)
|
|
|
|
{
|
|
|
|
struct stm_device *stm = stmf->stm;
|
|
|
|
struct stp_policy_id *id;
|
|
|
|
int ret = -EINVAL;
|
|
|
|
u32 size;
|
|
|
|
|
|
|
|
if (stmf->output.nr_chans)
|
|
|
|
return -EBUSY;
|
|
|
|
|
|
|
|
if (copy_from_user(&size, arg, sizeof(size)))
|
|
|
|
return -EFAULT;
|
|
|
|
|
|
|
|
if (size >= PATH_MAX + sizeof(*id))
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* size + 1 to make sure the .id string at the bottom is terminated,
|
|
|
|
* which is also why memdup_user() is not useful here
|
|
|
|
*/
|
|
|
|
id = kzalloc(size + 1, GFP_KERNEL);
|
|
|
|
if (!id)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
if (copy_from_user(id, arg, size)) {
|
|
|
|
ret = -EFAULT;
|
|
|
|
goto err_free;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (id->__reserved_0 || id->__reserved_1)
|
|
|
|
goto err_free;
|
|
|
|
|
|
|
|
if (id->width < 1 ||
|
|
|
|
id->width > PAGE_SIZE / stm->data->sw_mmiosz)
|
|
|
|
goto err_free;
|
|
|
|
|
|
|
|
ret = stm_file_assign(stmf, id->id, id->width);
|
|
|
|
if (ret)
|
|
|
|
goto err_free;
|
|
|
|
|
|
|
|
ret = 0;
|
|
|
|
|
|
|
|
if (stm->data->link)
|
|
|
|
ret = stm->data->link(stm->data, stmf->output.master,
|
|
|
|
stmf->output.channel);
|
|
|
|
|
|
|
|
if (ret) {
|
|
|
|
stm_output_free(stmf->stm, &stmf->output);
|
|
|
|
stm_put_device(stmf->stm);
|
|
|
|
}
|
|
|
|
|
|
|
|
err_free:
|
|
|
|
kfree(id);
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg)
|
|
|
|
{
|
|
|
|
struct stp_policy_id id = {
|
|
|
|
.size = sizeof(id),
|
|
|
|
.master = stmf->output.master,
|
|
|
|
.channel = stmf->output.channel,
|
|
|
|
.width = stmf->output.nr_chans,
|
|
|
|
.__reserved_0 = 0,
|
|
|
|
.__reserved_1 = 0,
|
|
|
|
};
|
|
|
|
|
|
|
|
return copy_to_user(arg, &id, id.size) ? -EFAULT : 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static long
|
|
|
|
stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
|
|
|
{
|
|
|
|
struct stm_file *stmf = file->private_data;
|
|
|
|
struct stm_data *stm_data = stmf->stm->data;
|
|
|
|
int err = -ENOTTY;
|
|
|
|
u64 options;
|
|
|
|
|
|
|
|
switch (cmd) {
|
|
|
|
case STP_POLICY_ID_SET:
|
|
|
|
err = stm_char_policy_set_ioctl(stmf, (void __user *)arg);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
|
|
|
return stm_char_policy_get_ioctl(stmf, (void __user *)arg);
|
|
|
|
|
|
|
|
case STP_POLICY_ID_GET:
|
|
|
|
return stm_char_policy_get_ioctl(stmf, (void __user *)arg);
|
|
|
|
|
|
|
|
case STP_SET_OPTIONS:
|
|
|
|
if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64)))
|
|
|
|
return -EFAULT;
|
|
|
|
|
|
|
|
if (stm_data->set_options)
|
|
|
|
err = stm_data->set_options(stm_data,
|
|
|
|
stmf->output.master,
|
|
|
|
stmf->output.channel,
|
|
|
|
stmf->output.nr_chans,
|
|
|
|
options);
|
|
|
|
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
|
|
static long
|
|
|
|
stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
|
|
|
{
|
|
|
|
return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
|
|
|
|
}
|
|
|
|
#else
|
|
|
|
#define stm_char_compat_ioctl NULL
|
|
|
|
#endif
|
|
|
|
|
|
|
|
static const struct file_operations stm_fops = {
|
|
|
|
.open = stm_char_open,
|
|
|
|
.release = stm_char_release,
|
|
|
|
.write = stm_char_write,
|
|
|
|
.mmap = stm_char_mmap,
|
|
|
|
.unlocked_ioctl = stm_char_ioctl,
|
|
|
|
.compat_ioctl = stm_char_compat_ioctl,
|
|
|
|
.llseek = no_llseek,
|
|
|
|
};
|
|
|
|
|
|
|
|
static void stm_device_release(struct device *dev)
|
|
|
|
{
|
|
|
|
struct stm_device *stm = to_stm_device(dev);
|
|
|
|
|
|
|
|
kfree(stm);
|
|
|
|
}
|
|
|
|
|
|
|
|
int stm_register_device(struct device *parent, struct stm_data *stm_data,
|
|
|
|
struct module *owner)
|
|
|
|
{
|
|
|
|
struct stm_device *stm;
|
|
|
|
unsigned int nmasters;
|
|
|
|
int err = -ENOMEM;
|
|
|
|
|
|
|
|
if (!stm_core_up)
|
|
|
|
return -EPROBE_DEFER;
|
|
|
|
|
|
|
|
if (!stm_data->packet || !stm_data->sw_nchannels)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
nmasters = stm_data->sw_end - stm_data->sw_start;
|
|
|
|
stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL);
|
|
|
|
if (!stm)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
stm->major = register_chrdev(0, stm_data->name, &stm_fops);
|
|
|
|
if (stm->major < 0)
|
|
|
|
goto err_free;
|
|
|
|
|
|
|
|
device_initialize(&stm->dev);
|
|
|
|
stm->dev.devt = MKDEV(stm->major, 0);
|
|
|
|
stm->dev.class = &stm_class;
|
|
|
|
stm->dev.parent = parent;
|
|
|
|
stm->dev.release = stm_device_release;
|
|
|
|
|
|
|
|
err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name);
|
|
|
|
if (err)
|
|
|
|
goto err_device;
|
|
|
|
|
|
|
|
err = device_add(&stm->dev);
|
|
|
|
if (err)
|
|
|
|
goto err_device;
|
|
|
|
|
2015-12-22 23:25:19 +08:00
|
|
|
mutex_init(&stm->link_mutex);
|
2015-09-22 20:47:10 +08:00
|
|
|
spin_lock_init(&stm->link_lock);
|
|
|
|
INIT_LIST_HEAD(&stm->link_list);
|
|
|
|
|
|
|
|
spin_lock_init(&stm->mc_lock);
|
|
|
|
mutex_init(&stm->policy_mutex);
|
|
|
|
stm->sw_nmasters = nmasters;
|
|
|
|
stm->owner = owner;
|
|
|
|
stm->data = stm_data;
|
|
|
|
stm_data->stm = stm;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
err_device:
|
|
|
|
put_device(&stm->dev);
|
|
|
|
err_free:
|
|
|
|
kfree(stm);
|
|
|
|
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(stm_register_device);
|
|
|
|
|
|
|
|
static void __stm_source_link_drop(struct stm_source_device *src,
|
|
|
|
struct stm_device *stm);
|
|
|
|
|
|
|
|
void stm_unregister_device(struct stm_data *stm_data)
|
|
|
|
{
|
|
|
|
struct stm_device *stm = stm_data->stm;
|
|
|
|
struct stm_source_device *src, *iter;
|
|
|
|
int i;
|
|
|
|
|
2015-12-22 23:25:19 +08:00
|
|
|
mutex_lock(&stm->link_mutex);
|
2015-09-22 20:47:10 +08:00
|
|
|
list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) {
|
|
|
|
__stm_source_link_drop(src, stm);
|
|
|
|
}
|
2015-12-22 23:25:19 +08:00
|
|
|
mutex_unlock(&stm->link_mutex);
|
2015-09-22 20:47:10 +08:00
|
|
|
|
|
|
|
synchronize_srcu(&stm_source_srcu);
|
|
|
|
|
|
|
|
unregister_chrdev(stm->major, stm_data->name);
|
|
|
|
|
|
|
|
mutex_lock(&stm->policy_mutex);
|
|
|
|
if (stm->policy)
|
|
|
|
stp_policy_unbind(stm->policy);
|
|
|
|
mutex_unlock(&stm->policy_mutex);
|
|
|
|
|
|
|
|
for (i = 0; i < stm->sw_nmasters; i++)
|
|
|
|
stp_master_free(stm, i);
|
|
|
|
|
|
|
|
device_unregister(&stm->dev);
|
|
|
|
stm_data->stm = NULL;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(stm_unregister_device);
|
|
|
|
|
2015-12-22 23:25:19 +08:00
|
|
|
/*
|
|
|
|
* stm::link_list access serialization uses a spinlock and a mutex; holding
|
|
|
|
* either of them guarantees that the list is stable; modification requires
|
|
|
|
* holding both of them.
|
|
|
|
*
|
|
|
|
* Lock ordering is as follows:
|
|
|
|
* stm::link_mutex
|
|
|
|
* stm::link_lock
|
|
|
|
* src::link_lock
|
|
|
|
*/
|
|
|
|
|
2015-09-22 20:47:10 +08:00
|
|
|
/**
|
|
|
|
* stm_source_link_add() - connect an stm_source device to an stm device
|
|
|
|
* @src: stm_source device
|
|
|
|
* @stm: stm device
|
|
|
|
*
|
|
|
|
* This function establishes a link from stm_source to an stm device so that
|
|
|
|
* the former can send out trace data to the latter.
|
|
|
|
*
|
|
|
|
* Return: 0 on success, -errno otherwise.
|
|
|
|
*/
|
|
|
|
static int stm_source_link_add(struct stm_source_device *src,
|
|
|
|
struct stm_device *stm)
|
|
|
|
{
|
|
|
|
char *id;
|
|
|
|
int err;
|
|
|
|
|
2015-12-22 23:25:19 +08:00
|
|
|
mutex_lock(&stm->link_mutex);
|
2015-09-22 20:47:10 +08:00
|
|
|
spin_lock(&stm->link_lock);
|
|
|
|
spin_lock(&src->link_lock);
|
|
|
|
|
|
|
|
/* src->link is dereferenced under stm_source_srcu but not the list */
|
|
|
|
rcu_assign_pointer(src->link, stm);
|
|
|
|
list_add_tail(&src->link_entry, &stm->link_list);
|
|
|
|
|
|
|
|
spin_unlock(&src->link_lock);
|
|
|
|
spin_unlock(&stm->link_lock);
|
2015-12-22 23:25:19 +08:00
|
|
|
mutex_unlock(&stm->link_mutex);
|
2015-09-22 20:47:10 +08:00
|
|
|
|
|
|
|
id = kstrdup(src->data->name, GFP_KERNEL);
|
|
|
|
if (id) {
|
|
|
|
src->policy_node =
|
|
|
|
stp_policy_node_lookup(stm, id);
|
|
|
|
|
|
|
|
kfree(id);
|
|
|
|
}
|
|
|
|
|
|
|
|
err = stm_output_assign(stm, src->data->nr_chans,
|
|
|
|
src->policy_node, &src->output);
|
|
|
|
|
|
|
|
if (src->policy_node)
|
|
|
|
stp_policy_node_put(src->policy_node);
|
|
|
|
|
|
|
|
if (err)
|
|
|
|
goto fail_detach;
|
|
|
|
|
|
|
|
/* this is to notify the STM device that a new link has been made */
|
|
|
|
if (stm->data->link)
|
|
|
|
err = stm->data->link(stm->data, src->output.master,
|
|
|
|
src->output.channel);
|
|
|
|
|
|
|
|
if (err)
|
|
|
|
goto fail_free_output;
|
|
|
|
|
|
|
|
/* this is to let the source carry out all necessary preparations */
|
|
|
|
if (src->data->link)
|
|
|
|
src->data->link(src->data);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
fail_free_output:
|
|
|
|
stm_output_free(stm, &src->output);
|
|
|
|
stm_put_device(stm);
|
|
|
|
|
|
|
|
fail_detach:
|
2015-12-22 23:25:19 +08:00
|
|
|
mutex_lock(&stm->link_mutex);
|
2015-09-22 20:47:10 +08:00
|
|
|
spin_lock(&stm->link_lock);
|
|
|
|
spin_lock(&src->link_lock);
|
|
|
|
|
|
|
|
rcu_assign_pointer(src->link, NULL);
|
|
|
|
list_del_init(&src->link_entry);
|
|
|
|
|
|
|
|
spin_unlock(&src->link_lock);
|
|
|
|
spin_unlock(&stm->link_lock);
|
2015-12-22 23:25:19 +08:00
|
|
|
mutex_unlock(&stm->link_mutex);
|
2015-09-22 20:47:10 +08:00
|
|
|
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* __stm_source_link_drop() - detach stm_source from an stm device
|
|
|
|
* @src: stm_source device
|
|
|
|
* @stm: stm device
|
|
|
|
*
|
|
|
|
* If @stm is @src::link, disconnect them from one another and put the
|
|
|
|
* reference on the @stm device.
|
|
|
|
*
|
2015-12-22 23:25:19 +08:00
|
|
|
* Caller must hold stm::link_mutex.
|
2015-09-22 20:47:10 +08:00
|
|
|
*/
|
|
|
|
static void __stm_source_link_drop(struct stm_source_device *src,
|
|
|
|
struct stm_device *stm)
|
|
|
|
{
|
2015-10-06 17:47:17 +08:00
|
|
|
struct stm_device *link;
|
|
|
|
|
2015-12-22 23:25:19 +08:00
|
|
|
lockdep_assert_held(&stm->link_mutex);
|
|
|
|
|
|
|
|
if (src->data->unlink)
|
|
|
|
src->data->unlink(src->data);
|
|
|
|
|
|
|
|
/* for stm::link_list modification, we hold both mutex and spinlock */
|
|
|
|
spin_lock(&stm->link_lock);
|
2015-09-22 20:47:10 +08:00
|
|
|
spin_lock(&src->link_lock);
|
2015-10-06 17:47:17 +08:00
|
|
|
link = srcu_dereference_check(src->link, &stm_source_srcu, 1);
|
|
|
|
if (WARN_ON_ONCE(link != stm)) {
|
2015-09-22 20:47:10 +08:00
|
|
|
spin_unlock(&src->link_lock);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2015-10-06 17:47:17 +08:00
|
|
|
stm_output_free(link, &src->output);
|
2015-09-22 20:47:10 +08:00
|
|
|
list_del_init(&src->link_entry);
|
|
|
|
/* matches stm_find_device() from stm_source_link_store() */
|
2015-10-06 17:47:17 +08:00
|
|
|
stm_put_device(link);
|
2015-09-22 20:47:10 +08:00
|
|
|
rcu_assign_pointer(src->link, NULL);
|
|
|
|
|
|
|
|
spin_unlock(&src->link_lock);
|
2015-12-22 23:25:19 +08:00
|
|
|
spin_unlock(&stm->link_lock);
|
2015-09-22 20:47:10 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* stm_source_link_drop() - detach stm_source from its stm device
|
|
|
|
* @src: stm_source device
|
|
|
|
*
|
|
|
|
* Unlinking means disconnecting from source's STM device; after this
|
|
|
|
* writes will be unsuccessful until it is linked to a new STM device.
|
|
|
|
*
|
|
|
|
* This will happen on "stm_source_link" sysfs attribute write to undo
|
|
|
|
* the existing link (if any), or on linked STM device's de-registration.
|
|
|
|
*/
|
|
|
|
static void stm_source_link_drop(struct stm_source_device *src)
|
|
|
|
{
|
|
|
|
struct stm_device *stm;
|
|
|
|
int idx;
|
|
|
|
|
|
|
|
idx = srcu_read_lock(&stm_source_srcu);
|
|
|
|
stm = srcu_dereference(src->link, &stm_source_srcu);
|
|
|
|
|
|
|
|
if (stm) {
|
2015-12-22 23:25:19 +08:00
|
|
|
mutex_lock(&stm->link_mutex);
|
2015-09-22 20:47:10 +08:00
|
|
|
__stm_source_link_drop(src, stm);
|
2015-12-22 23:25:19 +08:00
|
|
|
mutex_unlock(&stm->link_mutex);
|
2015-09-22 20:47:10 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
srcu_read_unlock(&stm_source_srcu, idx);
|
|
|
|
}
|
|
|
|
|
|
|
|
static ssize_t stm_source_link_show(struct device *dev,
|
|
|
|
struct device_attribute *attr,
|
|
|
|
char *buf)
|
|
|
|
{
|
|
|
|
struct stm_source_device *src = to_stm_source_device(dev);
|
|
|
|
struct stm_device *stm;
|
|
|
|
int idx, ret;
|
|
|
|
|
|
|
|
idx = srcu_read_lock(&stm_source_srcu);
|
|
|
|
stm = srcu_dereference(src->link, &stm_source_srcu);
|
|
|
|
ret = sprintf(buf, "%s\n",
|
|
|
|
stm ? dev_name(&stm->dev) : "<none>");
|
|
|
|
srcu_read_unlock(&stm_source_srcu, idx);
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static ssize_t stm_source_link_store(struct device *dev,
|
|
|
|
struct device_attribute *attr,
|
|
|
|
const char *buf, size_t count)
|
|
|
|
{
|
|
|
|
struct stm_source_device *src = to_stm_source_device(dev);
|
|
|
|
struct stm_device *link;
|
|
|
|
int err;
|
|
|
|
|
|
|
|
stm_source_link_drop(src);
|
|
|
|
|
|
|
|
link = stm_find_device(buf);
|
|
|
|
if (!link)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
err = stm_source_link_add(src, link);
|
|
|
|
if (err)
|
|
|
|
stm_put_device(link);
|
|
|
|
|
|
|
|
return err ? : count;
|
|
|
|
}
|
|
|
|
|
|
|
|
static DEVICE_ATTR_RW(stm_source_link);
|
|
|
|
|
|
|
|
static struct attribute *stm_source_attrs[] = {
|
|
|
|
&dev_attr_stm_source_link.attr,
|
|
|
|
NULL,
|
|
|
|
};
|
|
|
|
|
|
|
|
ATTRIBUTE_GROUPS(stm_source);
|
|
|
|
|
|
|
|
static struct class stm_source_class = {
|
|
|
|
.name = "stm_source",
|
|
|
|
.dev_groups = stm_source_groups,
|
|
|
|
};
|
|
|
|
|
|
|
|
static void stm_source_device_release(struct device *dev)
|
|
|
|
{
|
|
|
|
struct stm_source_device *src = to_stm_source_device(dev);
|
|
|
|
|
|
|
|
kfree(src);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* stm_source_register_device() - register an stm_source device
|
|
|
|
* @parent: parent device
|
|
|
|
* @data: device description structure
|
|
|
|
*
|
|
|
|
* This will create a device of stm_source class that can write
|
|
|
|
* data to an stm device once linked.
|
|
|
|
*
|
|
|
|
* Return: 0 on success, -errno otherwise.
|
|
|
|
*/
|
|
|
|
int stm_source_register_device(struct device *parent,
|
|
|
|
struct stm_source_data *data)
|
|
|
|
{
|
|
|
|
struct stm_source_device *src;
|
|
|
|
int err;
|
|
|
|
|
|
|
|
if (!stm_core_up)
|
|
|
|
return -EPROBE_DEFER;
|
|
|
|
|
|
|
|
src = kzalloc(sizeof(*src), GFP_KERNEL);
|
|
|
|
if (!src)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
device_initialize(&src->dev);
|
|
|
|
src->dev.class = &stm_source_class;
|
|
|
|
src->dev.parent = parent;
|
|
|
|
src->dev.release = stm_source_device_release;
|
|
|
|
|
|
|
|
err = kobject_set_name(&src->dev.kobj, "%s", data->name);
|
|
|
|
if (err)
|
|
|
|
goto err;
|
|
|
|
|
|
|
|
err = device_add(&src->dev);
|
|
|
|
if (err)
|
|
|
|
goto err;
|
|
|
|
|
|
|
|
spin_lock_init(&src->link_lock);
|
|
|
|
INIT_LIST_HEAD(&src->link_entry);
|
|
|
|
src->data = data;
|
|
|
|
data->src = src;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
err:
|
|
|
|
put_device(&src->dev);
|
|
|
|
kfree(src);
|
|
|
|
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(stm_source_register_device);
|
|
|
|
|
|
|
|
/**
|
|
|
|
* stm_source_unregister_device() - unregister an stm_source device
|
|
|
|
* @data: device description that was used to register the device
|
|
|
|
*
|
|
|
|
* This will remove a previously created stm_source device from the system.
|
|
|
|
*/
|
|
|
|
void stm_source_unregister_device(struct stm_source_data *data)
|
|
|
|
{
|
|
|
|
struct stm_source_device *src = data->src;
|
|
|
|
|
|
|
|
stm_source_link_drop(src);
|
|
|
|
|
|
|
|
device_destroy(&stm_source_class, src->dev.devt);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(stm_source_unregister_device);
|
|
|
|
|
|
|
|
int stm_source_write(struct stm_source_data *data, unsigned int chan,
|
|
|
|
const char *buf, size_t count)
|
|
|
|
{
|
|
|
|
struct stm_source_device *src = data->src;
|
|
|
|
struct stm_device *stm;
|
|
|
|
int idx;
|
|
|
|
|
|
|
|
if (!src->output.nr_chans)
|
|
|
|
return -ENODEV;
|
|
|
|
|
|
|
|
if (chan >= src->output.nr_chans)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
idx = srcu_read_lock(&stm_source_srcu);
|
|
|
|
|
|
|
|
stm = srcu_dereference(src->link, &stm_source_srcu);
|
|
|
|
if (stm)
|
|
|
|
stm_write(stm->data, src->output.master,
|
|
|
|
src->output.channel + chan,
|
|
|
|
buf, count);
|
|
|
|
else
|
|
|
|
count = -ENODEV;
|
|
|
|
|
|
|
|
srcu_read_unlock(&stm_source_srcu, idx);
|
|
|
|
|
|
|
|
return count;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(stm_source_write);
|
|
|
|
|
|
|
|
static int __init stm_core_init(void)
|
|
|
|
{
|
|
|
|
int err;
|
|
|
|
|
|
|
|
err = class_register(&stm_class);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
|
|
|
err = class_register(&stm_source_class);
|
|
|
|
if (err)
|
|
|
|
goto err_stm;
|
|
|
|
|
|
|
|
err = stp_configfs_init();
|
|
|
|
if (err)
|
|
|
|
goto err_src;
|
|
|
|
|
|
|
|
init_srcu_struct(&stm_source_srcu);
|
|
|
|
|
|
|
|
stm_core_up++;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
err_src:
|
|
|
|
class_unregister(&stm_source_class);
|
|
|
|
err_stm:
|
|
|
|
class_unregister(&stm_class);
|
|
|
|
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
module_init(stm_core_init);
|
|
|
|
|
|
|
|
static void __exit stm_core_exit(void)
|
|
|
|
{
|
|
|
|
cleanup_srcu_struct(&stm_source_srcu);
|
|
|
|
class_unregister(&stm_source_class);
|
|
|
|
class_unregister(&stm_class);
|
|
|
|
stp_configfs_exit();
|
|
|
|
}
|
|
|
|
|
|
|
|
module_exit(stm_core_exit);
|
|
|
|
|
|
|
|
MODULE_LICENSE("GPL v2");
|
|
|
|
MODULE_DESCRIPTION("System Trace Module device class");
|
|
|
|
MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
|