415 lines
9.9 KiB
C
415 lines
9.9 KiB
C
/*
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* PowerNV LPC bus handling.
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*
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* Copyright 2013 IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/of.h>
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#include <linux/bug.h>
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#include <linux/debugfs.h>
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#include <linux/io.h>
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#include <linux/slab.h>
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#include <asm/machdep.h>
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#include <asm/firmware.h>
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#include <asm/xics.h>
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#include <asm/opal.h>
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#include <asm/prom.h>
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#include <asm/uaccess.h>
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#include <asm/debug.h>
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static int opal_lpc_chip_id = -1;
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static u8 opal_lpc_inb(unsigned long port)
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{
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int64_t rc;
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__be32 data;
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if (opal_lpc_chip_id < 0 || port > 0xffff)
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return 0xff;
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rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 1);
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return rc ? 0xff : be32_to_cpu(data);
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}
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static __le16 __opal_lpc_inw(unsigned long port)
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{
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int64_t rc;
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__be32 data;
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if (opal_lpc_chip_id < 0 || port > 0xfffe)
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return 0xffff;
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if (port & 1)
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return (__le16)opal_lpc_inb(port) << 8 | opal_lpc_inb(port + 1);
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rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 2);
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return rc ? 0xffff : be32_to_cpu(data);
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}
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static u16 opal_lpc_inw(unsigned long port)
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{
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return le16_to_cpu(__opal_lpc_inw(port));
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}
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static __le32 __opal_lpc_inl(unsigned long port)
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{
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int64_t rc;
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__be32 data;
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if (opal_lpc_chip_id < 0 || port > 0xfffc)
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return 0xffffffff;
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if (port & 3)
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return (__le32)opal_lpc_inb(port ) << 24 |
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(__le32)opal_lpc_inb(port + 1) << 16 |
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(__le32)opal_lpc_inb(port + 2) << 8 |
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opal_lpc_inb(port + 3);
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rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 4);
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return rc ? 0xffffffff : be32_to_cpu(data);
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}
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static u32 opal_lpc_inl(unsigned long port)
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{
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return le32_to_cpu(__opal_lpc_inl(port));
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}
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static void opal_lpc_outb(u8 val, unsigned long port)
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{
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if (opal_lpc_chip_id < 0 || port > 0xffff)
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return;
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opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 1);
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}
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static void __opal_lpc_outw(__le16 val, unsigned long port)
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{
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if (opal_lpc_chip_id < 0 || port > 0xfffe)
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return;
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if (port & 1) {
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opal_lpc_outb(val >> 8, port);
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opal_lpc_outb(val , port + 1);
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return;
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}
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opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 2);
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}
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static void opal_lpc_outw(u16 val, unsigned long port)
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{
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__opal_lpc_outw(cpu_to_le16(val), port);
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}
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static void __opal_lpc_outl(__le32 val, unsigned long port)
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{
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if (opal_lpc_chip_id < 0 || port > 0xfffc)
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return;
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if (port & 3) {
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opal_lpc_outb(val >> 24, port);
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opal_lpc_outb(val >> 16, port + 1);
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opal_lpc_outb(val >> 8, port + 2);
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opal_lpc_outb(val , port + 3);
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return;
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}
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opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 4);
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}
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static void opal_lpc_outl(u32 val, unsigned long port)
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{
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__opal_lpc_outl(cpu_to_le32(val), port);
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}
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static void opal_lpc_insb(unsigned long p, void *b, unsigned long c)
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{
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u8 *ptr = b;
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while(c--)
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*(ptr++) = opal_lpc_inb(p);
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}
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static void opal_lpc_insw(unsigned long p, void *b, unsigned long c)
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{
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__le16 *ptr = b;
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while(c--)
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*(ptr++) = __opal_lpc_inw(p);
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}
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static void opal_lpc_insl(unsigned long p, void *b, unsigned long c)
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{
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__le32 *ptr = b;
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while(c--)
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*(ptr++) = __opal_lpc_inl(p);
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}
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static void opal_lpc_outsb(unsigned long p, const void *b, unsigned long c)
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{
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const u8 *ptr = b;
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while(c--)
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opal_lpc_outb(*(ptr++), p);
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}
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static void opal_lpc_outsw(unsigned long p, const void *b, unsigned long c)
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{
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const __le16 *ptr = b;
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while(c--)
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__opal_lpc_outw(*(ptr++), p);
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}
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static void opal_lpc_outsl(unsigned long p, const void *b, unsigned long c)
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{
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const __le32 *ptr = b;
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while(c--)
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__opal_lpc_outl(*(ptr++), p);
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}
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static const struct ppc_pci_io opal_lpc_io = {
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.inb = opal_lpc_inb,
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.inw = opal_lpc_inw,
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.inl = opal_lpc_inl,
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.outb = opal_lpc_outb,
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.outw = opal_lpc_outw,
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.outl = opal_lpc_outl,
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.insb = opal_lpc_insb,
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.insw = opal_lpc_insw,
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.insl = opal_lpc_insl,
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.outsb = opal_lpc_outsb,
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.outsw = opal_lpc_outsw,
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.outsl = opal_lpc_outsl,
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};
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#ifdef CONFIG_DEBUG_FS
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struct lpc_debugfs_entry {
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enum OpalLPCAddressType lpc_type;
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};
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static ssize_t lpc_debug_read(struct file *filp, char __user *ubuf,
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size_t count, loff_t *ppos)
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{
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struct lpc_debugfs_entry *lpc = filp->private_data;
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u32 data, pos, len, todo;
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int rc;
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if (!access_ok(VERIFY_WRITE, ubuf, count))
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return -EFAULT;
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todo = count;
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while (todo) {
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pos = *ppos;
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/*
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* Select access size based on count and alignment and
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* access type. IO and MEM only support byte acceses,
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* FW supports all 3.
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*/
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len = 1;
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if (lpc->lpc_type == OPAL_LPC_FW) {
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if (todo > 3 && (pos & 3) == 0)
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len = 4;
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else if (todo > 1 && (pos & 1) == 0)
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len = 2;
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}
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rc = opal_lpc_read(opal_lpc_chip_id, lpc->lpc_type, pos,
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&data, len);
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if (rc)
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return -ENXIO;
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/*
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* Now there is some trickery with the data returned by OPAL
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* as it's the desired data right justified in a 32-bit BE
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* word.
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*
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* This is a very bad interface and I'm to blame for it :-(
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*
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* So we can't just apply a 32-bit swap to what comes from OPAL,
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* because user space expects the *bytes* to be in their proper
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* respective positions (ie, LPC position).
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*
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* So what we really want to do here is to shift data right
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* appropriately on a LE kernel.
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*
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* IE. If the LPC transaction has bytes B0, B1, B2 and B3 in that
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* order, we have in memory written to by OPAL at the "data"
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* pointer:
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*
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* Bytes: OPAL "data" LE "data"
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* 32-bit: B0 B1 B2 B3 B0B1B2B3 B3B2B1B0
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* 16-bit: B0 B1 0000B0B1 B1B00000
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* 8-bit: B0 000000B0 B0000000
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*
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* So a BE kernel will have the leftmost of the above in the MSB
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* and rightmost in the LSB and can just then "cast" the u32 "data"
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* down to the appropriate quantity and write it.
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*
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* However, an LE kernel can't. It doesn't need to swap because a
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* load from data followed by a store to user are going to preserve
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* the byte ordering which is the wire byte order which is what the
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* user wants, but in order to "crop" to the right size, we need to
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* shift right first.
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*/
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switch(len) {
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case 4:
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rc = __put_user((u32)data, (u32 __user *)ubuf);
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break;
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case 2:
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#ifdef __LITTLE_ENDIAN__
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data >>= 16;
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#endif
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rc = __put_user((u16)data, (u16 __user *)ubuf);
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break;
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default:
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#ifdef __LITTLE_ENDIAN__
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data >>= 24;
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#endif
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rc = __put_user((u8)data, (u8 __user *)ubuf);
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break;
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}
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if (rc)
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return -EFAULT;
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*ppos += len;
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ubuf += len;
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todo -= len;
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}
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return count;
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}
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static ssize_t lpc_debug_write(struct file *filp, const char __user *ubuf,
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size_t count, loff_t *ppos)
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{
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struct lpc_debugfs_entry *lpc = filp->private_data;
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u32 data, pos, len, todo;
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int rc;
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if (!access_ok(VERIFY_READ, ubuf, count))
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return -EFAULT;
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todo = count;
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while (todo) {
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pos = *ppos;
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/*
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* Select access size based on count and alignment and
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* access type. IO and MEM only support byte acceses,
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* FW supports all 3.
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*/
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len = 1;
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if (lpc->lpc_type == OPAL_LPC_FW) {
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if (todo > 3 && (pos & 3) == 0)
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len = 4;
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else if (todo > 1 && (pos & 1) == 0)
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len = 2;
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}
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/*
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* Similarly to the read case, we have some trickery here but
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* it's different to handle. We need to pass the value to OPAL in
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* a register whose layout depends on the access size. We want
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* to reproduce the memory layout of the user, however we aren't
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* doing a load from user and a store to another memory location
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* which would achieve that. Here we pass the value to OPAL via
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* a register which is expected to contain the "BE" interpretation
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* of the byte sequence. IE: for a 32-bit access, byte 0 should be
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* in the MSB. So here we *do* need to byteswap on LE.
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*
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* User bytes: LE "data" OPAL "data"
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* 32-bit: B0 B1 B2 B3 B3B2B1B0 B0B1B2B3
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* 16-bit: B0 B1 0000B1B0 0000B0B1
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* 8-bit: B0 000000B0 000000B0
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*/
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switch(len) {
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case 4:
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rc = __get_user(data, (u32 __user *)ubuf);
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data = cpu_to_be32(data);
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break;
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case 2:
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rc = __get_user(data, (u16 __user *)ubuf);
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data = cpu_to_be16(data);
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break;
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default:
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rc = __get_user(data, (u8 __user *)ubuf);
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break;
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}
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if (rc)
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return -EFAULT;
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rc = opal_lpc_write(opal_lpc_chip_id, lpc->lpc_type, pos,
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data, len);
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if (rc)
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return -ENXIO;
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*ppos += len;
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ubuf += len;
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todo -= len;
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}
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return count;
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}
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static const struct file_operations lpc_fops = {
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.read = lpc_debug_read,
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.write = lpc_debug_write,
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.open = simple_open,
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.llseek = default_llseek,
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};
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static int opal_lpc_debugfs_create_type(struct dentry *folder,
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const char *fname,
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enum OpalLPCAddressType type)
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{
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struct lpc_debugfs_entry *entry;
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entry = kzalloc(sizeof(*entry), GFP_KERNEL);
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if (!entry)
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return -ENOMEM;
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entry->lpc_type = type;
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debugfs_create_file(fname, 0600, folder, entry, &lpc_fops);
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return 0;
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}
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static int opal_lpc_init_debugfs(void)
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{
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struct dentry *root;
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int rc = 0;
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if (opal_lpc_chip_id < 0)
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return -ENODEV;
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root = debugfs_create_dir("lpc", powerpc_debugfs_root);
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rc |= opal_lpc_debugfs_create_type(root, "io", OPAL_LPC_IO);
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rc |= opal_lpc_debugfs_create_type(root, "mem", OPAL_LPC_MEM);
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rc |= opal_lpc_debugfs_create_type(root, "fw", OPAL_LPC_FW);
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return rc;
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}
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machine_device_initcall(powernv, opal_lpc_init_debugfs);
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#endif /* CONFIG_DEBUG_FS */
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void opal_lpc_init(void)
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{
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struct device_node *np;
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/*
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* Look for a Power8 LPC bus tagged as "primary",
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* we currently support only one though the OPAL APIs
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* support any number.
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*/
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for_each_compatible_node(np, NULL, "ibm,power8-lpc") {
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if (!of_device_is_available(np))
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continue;
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if (!of_get_property(np, "primary", NULL))
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continue;
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opal_lpc_chip_id = of_get_ibm_chip_id(np);
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break;
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}
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if (opal_lpc_chip_id < 0)
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return;
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/* Setup special IO ops */
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ppc_pci_io = opal_lpc_io;
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isa_io_special = true;
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pr_info("OPAL: Power8 LPC bus found, chip ID %d\n", opal_lpc_chip_id);
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}
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