mirror of https://gitee.com/openkylin/linux.git
717 lines
20 KiB
C
717 lines
20 KiB
C
/*
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* Bus driver for MIPS Common Device Memory Map (CDMM).
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*
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* Copyright (C) 2014-2015 Imagination Technologies Ltd.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/atomic.h>
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#include <linux/err.h>
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#include <linux/cpu.h>
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#include <linux/cpumask.h>
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#include <linux/io.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/smp.h>
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#include <asm/cdmm.h>
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#include <asm/hazards.h>
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#include <asm/mipsregs.h>
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/* Access control and status register fields */
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#define CDMM_ACSR_DEVTYPE_SHIFT 24
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#define CDMM_ACSR_DEVTYPE (255ul << CDMM_ACSR_DEVTYPE_SHIFT)
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#define CDMM_ACSR_DEVSIZE_SHIFT 16
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#define CDMM_ACSR_DEVSIZE (31ul << CDMM_ACSR_DEVSIZE_SHIFT)
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#define CDMM_ACSR_DEVREV_SHIFT 12
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#define CDMM_ACSR_DEVREV (15ul << CDMM_ACSR_DEVREV_SHIFT)
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#define CDMM_ACSR_UW (1ul << 3)
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#define CDMM_ACSR_UR (1ul << 2)
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#define CDMM_ACSR_SW (1ul << 1)
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#define CDMM_ACSR_SR (1ul << 0)
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/* Each block of device registers is 64 bytes */
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#define CDMM_DRB_SIZE 64
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#define to_mips_cdmm_driver(d) container_of(d, struct mips_cdmm_driver, drv)
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/* Default physical base address */
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static phys_addr_t mips_cdmm_default_base;
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/* Bus operations */
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static const struct mips_cdmm_device_id *
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mips_cdmm_lookup(const struct mips_cdmm_device_id *table,
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struct mips_cdmm_device *dev)
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{
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int ret = 0;
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for (; table->type; ++table) {
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ret = (dev->type == table->type);
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if (ret)
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break;
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}
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return ret ? table : NULL;
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}
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static int mips_cdmm_match(struct device *dev, struct device_driver *drv)
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{
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struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev);
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struct mips_cdmm_driver *cdrv = to_mips_cdmm_driver(drv);
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return mips_cdmm_lookup(cdrv->id_table, cdev) != NULL;
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}
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static int mips_cdmm_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
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struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev);
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int retval = 0;
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retval = add_uevent_var(env, "CDMM_CPU=%u", cdev->cpu);
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if (retval)
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return retval;
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retval = add_uevent_var(env, "CDMM_TYPE=0x%02x", cdev->type);
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if (retval)
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return retval;
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retval = add_uevent_var(env, "CDMM_REV=%u", cdev->rev);
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if (retval)
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return retval;
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retval = add_uevent_var(env, "MODALIAS=mipscdmm:t%02X", cdev->type);
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return retval;
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}
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/* Device attributes */
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#define CDMM_ATTR(name, fmt, arg...) \
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static ssize_t name##_show(struct device *_dev, \
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struct device_attribute *attr, char *buf) \
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{ \
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struct mips_cdmm_device *dev = to_mips_cdmm_device(_dev); \
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return sprintf(buf, fmt, arg); \
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} \
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static DEVICE_ATTR_RO(name);
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CDMM_ATTR(cpu, "%u\n", dev->cpu);
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CDMM_ATTR(type, "0x%02x\n", dev->type);
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CDMM_ATTR(revision, "%u\n", dev->rev);
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CDMM_ATTR(modalias, "mipscdmm:t%02X\n", dev->type);
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CDMM_ATTR(resource, "\t%016llx\t%016llx\t%016lx\n",
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(unsigned long long)dev->res.start,
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(unsigned long long)dev->res.end,
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dev->res.flags);
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static struct attribute *mips_cdmm_dev_attrs[] = {
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&dev_attr_cpu.attr,
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&dev_attr_type.attr,
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&dev_attr_revision.attr,
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&dev_attr_modalias.attr,
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&dev_attr_resource.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(mips_cdmm_dev);
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struct bus_type mips_cdmm_bustype = {
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.name = "cdmm",
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.dev_groups = mips_cdmm_dev_groups,
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.match = mips_cdmm_match,
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.uevent = mips_cdmm_uevent,
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};
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EXPORT_SYMBOL_GPL(mips_cdmm_bustype);
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/*
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* Standard driver callback helpers.
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*
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* All the CDMM driver callbacks need to be executed on the appropriate CPU from
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* workqueues. For the standard driver callbacks we need a work function
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* (mips_cdmm_{void,int}_work()) to do the actual call from the right CPU, and a
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* wrapper function (generated with BUILD_PERCPU_HELPER) to arrange for the work
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* function to be called on that CPU.
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*/
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/**
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* struct mips_cdmm_work_dev - Data for per-device call work.
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* @fn: CDMM driver callback function to call for the device.
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* @dev: CDMM device to pass to @fn.
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*/
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struct mips_cdmm_work_dev {
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void *fn;
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struct mips_cdmm_device *dev;
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};
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/**
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* mips_cdmm_void_work() - Call a void returning CDMM driver callback.
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* @data: struct mips_cdmm_work_dev pointer.
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*
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* A work_on_cpu() callback function to call an arbitrary CDMM driver callback
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* function which doesn't return a value.
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*/
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static long mips_cdmm_void_work(void *data)
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{
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struct mips_cdmm_work_dev *work = data;
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void (*fn)(struct mips_cdmm_device *) = work->fn;
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fn(work->dev);
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return 0;
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}
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/**
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* mips_cdmm_int_work() - Call an int returning CDMM driver callback.
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* @data: struct mips_cdmm_work_dev pointer.
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*
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* A work_on_cpu() callback function to call an arbitrary CDMM driver callback
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* function which returns an int.
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*/
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static long mips_cdmm_int_work(void *data)
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{
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struct mips_cdmm_work_dev *work = data;
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int (*fn)(struct mips_cdmm_device *) = work->fn;
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return fn(work->dev);
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}
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#define _BUILD_RET_void
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#define _BUILD_RET_int return
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/**
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* BUILD_PERCPU_HELPER() - Helper to call a CDMM driver callback on right CPU.
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* @_ret: Return type (void or int).
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* @_name: Name of CDMM driver callback function.
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*
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* Generates a specific device callback function to call a CDMM driver callback
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* function on the appropriate CPU for the device, and if applicable return the
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* result.
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*/
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#define BUILD_PERCPU_HELPER(_ret, _name) \
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static _ret mips_cdmm_##_name(struct device *dev) \
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{ \
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struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); \
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struct mips_cdmm_driver *cdrv = to_mips_cdmm_driver(dev->driver); \
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struct mips_cdmm_work_dev work = { \
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.fn = cdrv->_name, \
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.dev = cdev, \
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}; \
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\
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_BUILD_RET_##_ret work_on_cpu(cdev->cpu, \
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mips_cdmm_##_ret##_work, &work); \
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}
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/* Driver callback functions */
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BUILD_PERCPU_HELPER(int, probe) /* int mips_cdmm_probe(struct device) */
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BUILD_PERCPU_HELPER(int, remove) /* int mips_cdmm_remove(struct device) */
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BUILD_PERCPU_HELPER(void, shutdown) /* void mips_cdmm_shutdown(struct device) */
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/* Driver registration */
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/**
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* mips_cdmm_driver_register() - Register a CDMM driver.
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* @drv: CDMM driver information.
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*
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* Register a CDMM driver with the CDMM subsystem. The driver will be informed
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* of matching devices which are discovered.
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*
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* Returns: 0 on success.
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*/
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int mips_cdmm_driver_register(struct mips_cdmm_driver *drv)
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{
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drv->drv.bus = &mips_cdmm_bustype;
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if (drv->probe)
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drv->drv.probe = mips_cdmm_probe;
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if (drv->remove)
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drv->drv.remove = mips_cdmm_remove;
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if (drv->shutdown)
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drv->drv.shutdown = mips_cdmm_shutdown;
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return driver_register(&drv->drv);
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}
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EXPORT_SYMBOL_GPL(mips_cdmm_driver_register);
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/**
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* mips_cdmm_driver_unregister() - Unregister a CDMM driver.
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* @drv: CDMM driver information.
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*
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* Unregister a CDMM driver from the CDMM subsystem.
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*/
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void mips_cdmm_driver_unregister(struct mips_cdmm_driver *drv)
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{
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driver_unregister(&drv->drv);
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}
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EXPORT_SYMBOL_GPL(mips_cdmm_driver_unregister);
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/* CDMM initialisation and bus discovery */
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/**
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* struct mips_cdmm_bus - Info about CDMM bus.
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* @phys: Physical address at which it is mapped.
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* @regs: Virtual address where registers can be accessed.
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* @drbs: Total number of DRBs.
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* @drbs_reserved: Number of DRBs reserved.
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* @discovered: Whether the devices on the bus have been discovered yet.
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* @offline: Whether the CDMM bus is going offline (or very early
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* coming back online), in which case it should be
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* reconfigured each time.
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*/
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struct mips_cdmm_bus {
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phys_addr_t phys;
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void __iomem *regs;
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unsigned int drbs;
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unsigned int drbs_reserved;
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bool discovered;
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bool offline;
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};
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static struct mips_cdmm_bus mips_cdmm_boot_bus;
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static DEFINE_PER_CPU(struct mips_cdmm_bus *, mips_cdmm_buses);
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static atomic_t mips_cdmm_next_id = ATOMIC_INIT(-1);
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/**
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* mips_cdmm_get_bus() - Get the per-CPU CDMM bus information.
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*
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* Get information about the per-CPU CDMM bus, if the bus is present.
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*
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* The caller must prevent migration to another CPU, either by disabling
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* pre-emption or by running from a pinned kernel thread.
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*
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* Returns: Pointer to CDMM bus information for the current CPU.
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* May return ERR_PTR(-errno) in case of error, so check with
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* IS_ERR().
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*/
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static struct mips_cdmm_bus *mips_cdmm_get_bus(void)
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{
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struct mips_cdmm_bus *bus, **bus_p;
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unsigned long flags;
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unsigned int cpu;
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if (!cpu_has_cdmm)
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return ERR_PTR(-ENODEV);
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cpu = smp_processor_id();
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/* Avoid early use of per-cpu primitives before initialised */
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if (cpu == 0)
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return &mips_cdmm_boot_bus;
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/* Get bus pointer */
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bus_p = per_cpu_ptr(&mips_cdmm_buses, cpu);
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local_irq_save(flags);
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bus = *bus_p;
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/* Attempt allocation if NULL */
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if (unlikely(!bus)) {
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bus = kzalloc(sizeof(*bus), GFP_ATOMIC);
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if (unlikely(!bus))
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bus = ERR_PTR(-ENOMEM);
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else
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*bus_p = bus;
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}
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local_irq_restore(flags);
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return bus;
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}
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/**
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* mips_cdmm_cur_base() - Find current physical base address of CDMM region.
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*
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* Returns: Physical base address of CDMM region according to cdmmbase CP0
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* register, or 0 if the CDMM region is disabled.
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*/
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static phys_addr_t mips_cdmm_cur_base(void)
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{
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unsigned long cdmmbase = read_c0_cdmmbase();
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if (!(cdmmbase & MIPS_CDMMBASE_EN))
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return 0;
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return (cdmmbase >> MIPS_CDMMBASE_ADDR_SHIFT)
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<< MIPS_CDMMBASE_ADDR_START;
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}
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/**
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* mips_cdmm_setup() - Ensure the CDMM bus is initialised and usable.
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* @bus: Pointer to bus information for current CPU.
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* IS_ERR(bus) is checked, so no need for caller to check.
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*
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* The caller must prevent migration to another CPU, either by disabling
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* pre-emption or by running from a pinned kernel thread.
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*
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* Returns 0 on success, -errno on failure.
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*/
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static int mips_cdmm_setup(struct mips_cdmm_bus *bus)
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{
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unsigned long cdmmbase, flags;
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int ret = 0;
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if (IS_ERR(bus))
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return PTR_ERR(bus);
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local_irq_save(flags);
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/* Don't set up bus a second time unless marked offline */
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if (bus->offline) {
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/* If CDMM region is still set up, nothing to do */
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if (bus->phys == mips_cdmm_cur_base())
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goto out;
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/*
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* The CDMM region isn't set up as expected, so it needs
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* reconfiguring, but then we can stop checking it.
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*/
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bus->offline = false;
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} else if (bus->phys > 1) {
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goto out;
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}
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/* If the CDMM region is already configured, inherit that setup */
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if (!bus->phys)
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bus->phys = mips_cdmm_cur_base();
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/* Otherwise, ask platform code for suggestions */
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if (!bus->phys && mips_cdmm_phys_base)
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bus->phys = mips_cdmm_phys_base();
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/* Otherwise, copy what other CPUs have done */
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if (!bus->phys)
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bus->phys = mips_cdmm_default_base;
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/* Otherwise, complain once */
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if (!bus->phys) {
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bus->phys = 1;
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/*
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* If you hit this, either your bootloader needs to set up the
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* CDMM on the boot CPU, or else you need to implement
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* mips_cdmm_phys_base() for your platform (see asm/cdmm.h).
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*/
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pr_err("cdmm%u: Failed to choose a physical base\n",
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smp_processor_id());
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}
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/* Already complained? */
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if (bus->phys == 1) {
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ret = -ENOMEM;
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goto out;
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}
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/* Record our success for other CPUs to copy */
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mips_cdmm_default_base = bus->phys;
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pr_debug("cdmm%u: Enabling CDMM region at %pa\n",
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smp_processor_id(), &bus->phys);
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/* Enable CDMM */
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cdmmbase = read_c0_cdmmbase();
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cdmmbase &= (1ul << MIPS_CDMMBASE_ADDR_SHIFT) - 1;
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cdmmbase |= (bus->phys >> MIPS_CDMMBASE_ADDR_START)
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<< MIPS_CDMMBASE_ADDR_SHIFT;
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cdmmbase |= MIPS_CDMMBASE_EN;
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write_c0_cdmmbase(cdmmbase);
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tlbw_use_hazard();
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bus->regs = (void __iomem *)CKSEG1ADDR(bus->phys);
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bus->drbs = 1 + ((cdmmbase & MIPS_CDMMBASE_SIZE) >>
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MIPS_CDMMBASE_SIZE_SHIFT);
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bus->drbs_reserved = !!(cdmmbase & MIPS_CDMMBASE_CI);
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out:
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local_irq_restore(flags);
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return ret;
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}
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/**
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* mips_cdmm_early_probe() - Minimally probe for a specific device on CDMM.
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* @dev_type: CDMM type code to look for.
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*
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* Minimally configure the in-CPU Common Device Memory Map (CDMM) and look for a
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* specific device. This can be used to find a device very early in boot for
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* example to configure an early FDC console device.
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*
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* The caller must prevent migration to another CPU, either by disabling
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* pre-emption or by running from a pinned kernel thread.
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*
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* Returns: MMIO pointer to device memory. The caller can read the ACSR
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* register to find more information about the device (such as the
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* version number or the number of blocks).
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* May return IOMEM_ERR_PTR(-errno) in case of error, so check with
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* IS_ERR().
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*/
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void __iomem *mips_cdmm_early_probe(unsigned int dev_type)
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{
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struct mips_cdmm_bus *bus;
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void __iomem *cdmm;
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u32 acsr;
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unsigned int drb, type, size;
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int err;
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if (WARN_ON(!dev_type))
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return IOMEM_ERR_PTR(-ENODEV);
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bus = mips_cdmm_get_bus();
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err = mips_cdmm_setup(bus);
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if (err)
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return IOMEM_ERR_PTR(err);
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/* Skip the first block if it's reserved for more registers */
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drb = bus->drbs_reserved;
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cdmm = bus->regs;
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/* Look for a specific device type */
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for (; drb < bus->drbs; drb += size + 1) {
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acsr = readl(cdmm + drb * CDMM_DRB_SIZE);
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type = (acsr & CDMM_ACSR_DEVTYPE) >> CDMM_ACSR_DEVTYPE_SHIFT;
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if (type == dev_type)
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return cdmm + drb * CDMM_DRB_SIZE;
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size = (acsr & CDMM_ACSR_DEVSIZE) >> CDMM_ACSR_DEVSIZE_SHIFT;
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}
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return IOMEM_ERR_PTR(-ENODEV);
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}
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EXPORT_SYMBOL_GPL(mips_cdmm_early_probe);
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/**
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* mips_cdmm_release() - Release a removed CDMM device.
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* @dev: Device object
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*
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* Clean up the struct mips_cdmm_device for an unused CDMM device. This is
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* called automatically by the driver core when a device is removed.
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*/
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static void mips_cdmm_release(struct device *dev)
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{
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struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev);
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kfree(cdev);
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}
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/**
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* mips_cdmm_bus_discover() - Discover the devices on the CDMM bus.
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* @bus: CDMM bus information, must already be set up.
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*/
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static void mips_cdmm_bus_discover(struct mips_cdmm_bus *bus)
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{
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void __iomem *cdmm;
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|
u32 acsr;
|
|
unsigned int drb, type, size, rev;
|
|
struct mips_cdmm_device *dev;
|
|
unsigned int cpu = smp_processor_id();
|
|
int ret = 0;
|
|
int id = 0;
|
|
|
|
/* Skip the first block if it's reserved for more registers */
|
|
drb = bus->drbs_reserved;
|
|
cdmm = bus->regs;
|
|
|
|
/* Discover devices */
|
|
bus->discovered = true;
|
|
pr_info("cdmm%u discovery (%u blocks)\n", cpu, bus->drbs);
|
|
for (; drb < bus->drbs; drb += size + 1) {
|
|
acsr = readl(cdmm + drb * CDMM_DRB_SIZE);
|
|
type = (acsr & CDMM_ACSR_DEVTYPE) >> CDMM_ACSR_DEVTYPE_SHIFT;
|
|
size = (acsr & CDMM_ACSR_DEVSIZE) >> CDMM_ACSR_DEVSIZE_SHIFT;
|
|
rev = (acsr & CDMM_ACSR_DEVREV) >> CDMM_ACSR_DEVREV_SHIFT;
|
|
|
|
if (!type)
|
|
continue;
|
|
|
|
pr_info("cdmm%u-%u: @%u (%#x..%#x), type 0x%02x, rev %u\n",
|
|
cpu, id, drb, drb * CDMM_DRB_SIZE,
|
|
(drb + size + 1) * CDMM_DRB_SIZE - 1,
|
|
type, rev);
|
|
|
|
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
|
|
if (!dev)
|
|
break;
|
|
|
|
dev->cpu = cpu;
|
|
dev->res.start = bus->phys + drb * CDMM_DRB_SIZE;
|
|
dev->res.end = bus->phys +
|
|
(drb + size + 1) * CDMM_DRB_SIZE - 1;
|
|
dev->res.flags = IORESOURCE_MEM;
|
|
dev->type = type;
|
|
dev->rev = rev;
|
|
dev->dev.parent = get_cpu_device(cpu);
|
|
dev->dev.bus = &mips_cdmm_bustype;
|
|
dev->dev.id = atomic_inc_return(&mips_cdmm_next_id);
|
|
dev->dev.release = mips_cdmm_release;
|
|
|
|
dev_set_name(&dev->dev, "cdmm%u-%u", cpu, id);
|
|
++id;
|
|
ret = device_register(&dev->dev);
|
|
if (ret) {
|
|
put_device(&dev->dev);
|
|
kfree(dev);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* CPU hotplug and initialisation
|
|
*
|
|
* All the CDMM driver callbacks need to be executed on the appropriate CPU from
|
|
* workqueues. For the CPU callbacks, they need to be called for all devices on
|
|
* that CPU, so the work function calls bus_for_each_dev, using a helper
|
|
* (generated with BUILD_PERDEV_HELPER) to call the driver callback if the
|
|
* device's CPU matches.
|
|
*/
|
|
|
|
/**
|
|
* BUILD_PERDEV_HELPER() - Helper to call a CDMM driver callback if CPU matches.
|
|
* @_name: Name of CDMM driver callback function.
|
|
*
|
|
* Generates a bus_for_each_dev callback function to call a specific CDMM driver
|
|
* callback function for the device if the device's CPU matches that pointed to
|
|
* by the data argument.
|
|
*
|
|
* This is used for informing drivers for all devices on a given CPU of some
|
|
* event (such as the CPU going online/offline).
|
|
*
|
|
* It is expected to already be called from the appropriate CPU.
|
|
*/
|
|
#define BUILD_PERDEV_HELPER(_name) \
|
|
static int mips_cdmm_##_name##_helper(struct device *dev, void *data) \
|
|
{ \
|
|
struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); \
|
|
struct mips_cdmm_driver *cdrv; \
|
|
unsigned int cpu = *(unsigned int *)data; \
|
|
\
|
|
if (cdev->cpu != cpu || !dev->driver) \
|
|
return 0; \
|
|
\
|
|
cdrv = to_mips_cdmm_driver(dev->driver); \
|
|
if (!cdrv->_name) \
|
|
return 0; \
|
|
return cdrv->_name(cdev); \
|
|
}
|
|
|
|
/* bus_for_each_dev callback helper functions */
|
|
BUILD_PERDEV_HELPER(cpu_down) /* int mips_cdmm_cpu_down_helper(...) */
|
|
BUILD_PERDEV_HELPER(cpu_up) /* int mips_cdmm_cpu_up_helper(...) */
|
|
|
|
/**
|
|
* mips_cdmm_bus_down() - Tear down the CDMM bus.
|
|
* @data: Pointer to unsigned int CPU number.
|
|
*
|
|
* This work_on_cpu callback function is executed on a given CPU to call the
|
|
* CDMM driver cpu_down callback for all devices on that CPU.
|
|
*/
|
|
static long mips_cdmm_bus_down(void *data)
|
|
{
|
|
struct mips_cdmm_bus *bus;
|
|
long ret;
|
|
|
|
/* Inform all the devices on the bus */
|
|
ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, data,
|
|
mips_cdmm_cpu_down_helper);
|
|
|
|
/*
|
|
* While bus is offline, each use of it should reconfigure it just in
|
|
* case it is first use when coming back online again.
|
|
*/
|
|
bus = mips_cdmm_get_bus();
|
|
if (!IS_ERR(bus))
|
|
bus->offline = true;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* mips_cdmm_bus_up() - Bring up the CDMM bus.
|
|
* @data: Pointer to unsigned int CPU number.
|
|
*
|
|
* This work_on_cpu callback function is executed on a given CPU to discover
|
|
* CDMM devices on that CPU, or to call the CDMM driver cpu_up callback for all
|
|
* devices already discovered on that CPU.
|
|
*
|
|
* It is used during initialisation and when CPUs are brought online.
|
|
*/
|
|
static long mips_cdmm_bus_up(void *data)
|
|
{
|
|
struct mips_cdmm_bus *bus;
|
|
long ret;
|
|
|
|
bus = mips_cdmm_get_bus();
|
|
ret = mips_cdmm_setup(bus);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* Bus now set up, so we can drop the offline flag if still set */
|
|
bus->offline = false;
|
|
|
|
if (!bus->discovered)
|
|
mips_cdmm_bus_discover(bus);
|
|
else
|
|
/* Inform all the devices on the bus */
|
|
ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, data,
|
|
mips_cdmm_cpu_up_helper);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* mips_cdmm_cpu_notify() - Take action when a CPU is going online or offline.
|
|
* @nb: CPU notifier block .
|
|
* @action: Event that has taken place (CPU_*).
|
|
* @data: CPU number.
|
|
*
|
|
* This notifier is used to keep the CDMM buses updated as CPUs are offlined and
|
|
* onlined. When CPUs go offline or come back online, so does their CDMM bus, so
|
|
* devices must be informed. Also when CPUs come online for the first time the
|
|
* devices on the CDMM bus need discovering.
|
|
*
|
|
* Returns: NOTIFY_OK if event was used.
|
|
* NOTIFY_DONE if we didn't care.
|
|
*/
|
|
static int mips_cdmm_cpu_notify(struct notifier_block *nb,
|
|
unsigned long action, void *data)
|
|
{
|
|
unsigned int cpu = (unsigned int)data;
|
|
|
|
switch (action & ~CPU_TASKS_FROZEN) {
|
|
case CPU_ONLINE:
|
|
case CPU_DOWN_FAILED:
|
|
work_on_cpu(cpu, mips_cdmm_bus_up, &cpu);
|
|
break;
|
|
case CPU_DOWN_PREPARE:
|
|
work_on_cpu(cpu, mips_cdmm_bus_down, &cpu);
|
|
break;
|
|
default:
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block mips_cdmm_cpu_nb = {
|
|
.notifier_call = mips_cdmm_cpu_notify,
|
|
};
|
|
|
|
/**
|
|
* mips_cdmm_init() - Initialise CDMM bus.
|
|
*
|
|
* Initialise CDMM bus, discover CDMM devices for online CPUs, and arrange for
|
|
* hotplug notifications so the CDMM drivers can be kept up to date.
|
|
*/
|
|
static int __init mips_cdmm_init(void)
|
|
{
|
|
unsigned int cpu;
|
|
int ret;
|
|
|
|
/* Register the bus */
|
|
ret = bus_register(&mips_cdmm_bustype);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* We want to be notified about new CPUs */
|
|
ret = register_cpu_notifier(&mips_cdmm_cpu_nb);
|
|
if (ret) {
|
|
pr_warn("cdmm: Failed to register CPU notifier\n");
|
|
goto out;
|
|
}
|
|
|
|
/* Discover devices on CDMM of online CPUs */
|
|
for_each_online_cpu(cpu)
|
|
work_on_cpu(cpu, mips_cdmm_bus_up, &cpu);
|
|
|
|
return 0;
|
|
out:
|
|
bus_unregister(&mips_cdmm_bustype);
|
|
return ret;
|
|
}
|
|
subsys_initcall(mips_cdmm_init);
|