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nvram.c

/*
 *  Copyright (C) 2002 Benjamin Herrenschmidt (benh@kernel.crashing.org)
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 *  Todo: - add support for the OF persistent properties
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/nvram.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/adb.h>
#include <linux/pmu.h>
#include <linux/bootmem.h>
#include <linux/completion.h>
#include <linux/spinlock.h>
#include <asm/sections.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/nvram.h>

#include "pmac.h"

#define DEBUG

#ifdef DEBUG
#define DBG(x...) printk(x)
#else
#define DBG(x...)
#endif

#define NVRAM_SIZE            0x2000      /* 8kB of non-volatile RAM */

#define CORE99_SIGNATURE      0x5a
#define CORE99_ADLER_START    0x14

/* On Core99, nvram is either a sharp, a micron or an AMD flash */
#define SM_FLASH_STATUS_DONE  0x80
#define SM_FLASH_STATUS_ERR   0x38

#define SM_FLASH_CMD_ERASE_CONFIRM  0xd0
#define SM_FLASH_CMD_ERASE_SETUP    0x20
#define SM_FLASH_CMD_RESET          0xff
#define SM_FLASH_CMD_WRITE_SETUP    0x40
#define SM_FLASH_CMD_CLEAR_STATUS   0x50
#define SM_FLASH_CMD_READ_STATUS    0x70

/* CHRP NVRAM header */
struct chrp_header {
  u8        signature;
  u8        cksum;
  u16       len;
  char          name[12];
  u8        data[0];
};

struct core99_header {
  struct chrp_header    hdr;
  u32             adler;
  u32             generation;
  u32             reserved[2];
};

/*
 * Read and write the non-volatile RAM on PowerMacs and CHRP machines.
 */
static int nvram_naddrs;
static volatile unsigned char __iomem *nvram_data;
static int is_core_99;
static int core99_bank = 0;
static int nvram_partitions[3];
// XXX Turn that into a sem
static DEFINE_SPINLOCK(nv_lock);

static int (*core99_write_bank)(int bank, u8* datas);
static int (*core99_erase_bank)(int bank);

static char *nvram_image;


static unsigned char core99_nvram_read_byte(int addr)
{
      if (nvram_image == NULL)
            return 0xff;
      return nvram_image[addr];
}

static void core99_nvram_write_byte(int addr, unsigned char val)
{
      if (nvram_image == NULL)
            return;
      nvram_image[addr] = val;
}

static ssize_t core99_nvram_read(char *buf, size_t count, loff_t *index)
{
      int i;

      if (nvram_image == NULL)
            return -ENODEV;
      if (*index > NVRAM_SIZE)
            return 0;

      i = *index;
      if (i + count > NVRAM_SIZE)
            count = NVRAM_SIZE - i;

      memcpy(buf, &nvram_image[i], count);
      *index = i + count;
      return count;
}

static ssize_t core99_nvram_write(char *buf, size_t count, loff_t *index)
{
      int i;

      if (nvram_image == NULL)
            return -ENODEV;
      if (*index > NVRAM_SIZE)
            return 0;

      i = *index;
      if (i + count > NVRAM_SIZE)
            count = NVRAM_SIZE - i;

      memcpy(&nvram_image[i], buf, count);
      *index = i + count;
      return count;
}

static ssize_t core99_nvram_size(void)
{
      if (nvram_image == NULL)
            return -ENODEV;
      return NVRAM_SIZE;
}

#ifdef CONFIG_PPC32
static volatile unsigned char __iomem *nvram_addr;
static int nvram_mult;

static unsigned char direct_nvram_read_byte(int addr)
{
      return in_8(&nvram_data[(addr & (NVRAM_SIZE - 1)) * nvram_mult]);
}

static void direct_nvram_write_byte(int addr, unsigned char val)
{
      out_8(&nvram_data[(addr & (NVRAM_SIZE - 1)) * nvram_mult], val);
}


static unsigned char indirect_nvram_read_byte(int addr)
{
      unsigned char val;
      unsigned long flags;

      spin_lock_irqsave(&nv_lock, flags);
      out_8(nvram_addr, addr >> 5);
      val = in_8(&nvram_data[(addr & 0x1f) << 4]);
      spin_unlock_irqrestore(&nv_lock, flags);

      return val;
}

static void indirect_nvram_write_byte(int addr, unsigned char val)
{
      unsigned long flags;

      spin_lock_irqsave(&nv_lock, flags);
      out_8(nvram_addr, addr >> 5);
      out_8(&nvram_data[(addr & 0x1f) << 4], val);
      spin_unlock_irqrestore(&nv_lock, flags);
}


#ifdef CONFIG_ADB_PMU

static void pmu_nvram_complete(struct adb_request *req)
{
      if (req->arg)
            complete((struct completion *)req->arg);
}

static unsigned char pmu_nvram_read_byte(int addr)
{
      struct adb_request req;
      DECLARE_COMPLETION_ONSTACK(req_complete);
      
      req.arg = system_state == SYSTEM_RUNNING ? &req_complete : NULL;
      if (pmu_request(&req, pmu_nvram_complete, 3, PMU_READ_NVRAM,
                  (addr >> 8) & 0xff, addr & 0xff))
            return 0xff;
      if (system_state == SYSTEM_RUNNING)
            wait_for_completion(&req_complete);
      while (!req.complete)
            pmu_poll();
      return req.reply[0];
}

static void pmu_nvram_write_byte(int addr, unsigned char val)
{
      struct adb_request req;
      DECLARE_COMPLETION_ONSTACK(req_complete);
      
      req.arg = system_state == SYSTEM_RUNNING ? &req_complete : NULL;
      if (pmu_request(&req, pmu_nvram_complete, 4, PMU_WRITE_NVRAM,
                  (addr >> 8) & 0xff, addr & 0xff, val))
            return;
      if (system_state == SYSTEM_RUNNING)
            wait_for_completion(&req_complete);
      while (!req.complete)
            pmu_poll();
}

#endif /* CONFIG_ADB_PMU */
#endif /* CONFIG_PPC32 */

static u8 chrp_checksum(struct chrp_header* hdr)
{
      u8 *ptr;
      u16 sum = hdr->signature;
      for (ptr = (u8 *)&hdr->len; ptr < hdr->data; ptr++)
            sum += *ptr;
      while (sum > 0xFF)
            sum = (sum & 0xFF) + (sum>>8);
      return sum;
}

static u32 core99_calc_adler(u8 *buffer)
{
      int cnt;
      u32 low, high;

      buffer += CORE99_ADLER_START;
      low = 1;
      high = 0;
      for (cnt=0; cnt<(NVRAM_SIZE-CORE99_ADLER_START); cnt++) {
            if ((cnt % 5000) == 0) {
                  high  %= 65521UL;
                  high %= 65521UL;
            }
            low += buffer[cnt];
            high += low;
      }
      low  %= 65521UL;
      high %= 65521UL;

      return (high << 16) | low;
}

static u32 core99_check(u8* datas)
{
      struct core99_header* hdr99 = (struct core99_header*)datas;

      if (hdr99->hdr.signature != CORE99_SIGNATURE) {
            DBG("Invalid signature\n");
            return 0;
      }
      if (hdr99->hdr.cksum != chrp_checksum(&hdr99->hdr)) {
            DBG("Invalid checksum\n");
            return 0;
      }
      if (hdr99->adler != core99_calc_adler(datas)) {
            DBG("Invalid adler\n");
            return 0;
      }
      return hdr99->generation;
}

static int sm_erase_bank(int bank)
{
      int stat, i;
      unsigned long timeout;

      u8 __iomem *base = (u8 __iomem *)nvram_data + core99_bank*NVRAM_SIZE;

            DBG("nvram: Sharp/Micron Erasing bank %d...\n", bank);

      out_8(base, SM_FLASH_CMD_ERASE_SETUP);
      out_8(base, SM_FLASH_CMD_ERASE_CONFIRM);
      timeout = 0;
      do {
            if (++timeout > 1000000) {
                  printk(KERN_ERR "nvram: Sharp/Micron flash erase timeout !\n");
                  break;
            }
            out_8(base, SM_FLASH_CMD_READ_STATUS);
            stat = in_8(base);
      } while (!(stat & SM_FLASH_STATUS_DONE));

      out_8(base, SM_FLASH_CMD_CLEAR_STATUS);
      out_8(base, SM_FLASH_CMD_RESET);

      for (i=0; i<NVRAM_SIZE; i++)
            if (base[i] != 0xff) {
                  printk(KERN_ERR "nvram: Sharp/Micron flash erase failed !\n");
                  return -ENXIO;
            }
      return 0;
}

static int sm_write_bank(int bank, u8* datas)
{
      int i, stat = 0;
      unsigned long timeout;

      u8 __iomem *base = (u8 __iomem *)nvram_data + core99_bank*NVRAM_SIZE;

            DBG("nvram: Sharp/Micron Writing bank %d...\n", bank);

      for (i=0; i<NVRAM_SIZE; i++) {
            out_8(base+i, SM_FLASH_CMD_WRITE_SETUP);
            udelay(1);
            out_8(base+i, datas[i]);
            timeout = 0;
            do {
                  if (++timeout > 1000000) {
                        printk(KERN_ERR "nvram: Sharp/Micron flash write timeout !\n");
                        break;
                  }
                  out_8(base, SM_FLASH_CMD_READ_STATUS);
                  stat = in_8(base);
            } while (!(stat & SM_FLASH_STATUS_DONE));
            if (!(stat & SM_FLASH_STATUS_DONE))
                  break;
      }
      out_8(base, SM_FLASH_CMD_CLEAR_STATUS);
      out_8(base, SM_FLASH_CMD_RESET);
      for (i=0; i<NVRAM_SIZE; i++)
            if (base[i] != datas[i]) {
                  printk(KERN_ERR "nvram: Sharp/Micron flash write failed !\n");
                  return -ENXIO;
            }
      return 0;
}

static int amd_erase_bank(int bank)
{
      int i, stat = 0;
      unsigned long timeout;

      u8 __iomem *base = (u8 __iomem *)nvram_data + core99_bank*NVRAM_SIZE;

            DBG("nvram: AMD Erasing bank %d...\n", bank);

      /* Unlock 1 */
      out_8(base+0x555, 0xaa);
      udelay(1);
      /* Unlock 2 */
      out_8(base+0x2aa, 0x55);
      udelay(1);

      /* Sector-Erase */
      out_8(base+0x555, 0x80);
      udelay(1);
      out_8(base+0x555, 0xaa);
      udelay(1);
      out_8(base+0x2aa, 0x55);
      udelay(1);
      out_8(base, 0x30);
      udelay(1);

      timeout = 0;
      do {
            if (++timeout > 1000000) {
                  printk(KERN_ERR "nvram: AMD flash erase timeout !\n");
                  break;
            }
            stat = in_8(base) ^ in_8(base);
      } while (stat != 0);
      
      /* Reset */
      out_8(base, 0xf0);
      udelay(1);
      
      for (i=0; i<NVRAM_SIZE; i++)
            if (base[i] != 0xff) {
                  printk(KERN_ERR "nvram: AMD flash erase failed !\n");
                  return -ENXIO;
            }
      return 0;
}

static int amd_write_bank(int bank, u8* datas)
{
      int i, stat = 0;
      unsigned long timeout;

      u8 __iomem *base = (u8 __iomem *)nvram_data + core99_bank*NVRAM_SIZE;

            DBG("nvram: AMD Writing bank %d...\n", bank);

      for (i=0; i<NVRAM_SIZE; i++) {
            /* Unlock 1 */
            out_8(base+0x555, 0xaa);
            udelay(1);
            /* Unlock 2 */
            out_8(base+0x2aa, 0x55);
            udelay(1);

            /* Write single word */
            out_8(base+0x555, 0xa0);
            udelay(1);
            out_8(base+i, datas[i]);
            
            timeout = 0;
            do {
                  if (++timeout > 1000000) {
                        printk(KERN_ERR "nvram: AMD flash write timeout !\n");
                        break;
                  }
                  stat = in_8(base) ^ in_8(base);
            } while (stat != 0);
            if (stat != 0)
                  break;
      }

      /* Reset */
      out_8(base, 0xf0);
      udelay(1);

      for (i=0; i<NVRAM_SIZE; i++)
            if (base[i] != datas[i]) {
                  printk(KERN_ERR "nvram: AMD flash write failed !\n");
                  return -ENXIO;
            }
      return 0;
}

static void __init lookup_partitions(void)
{
      u8 buffer[17];
      int i, offset;
      struct chrp_header* hdr;

      if (pmac_newworld) {
            nvram_partitions[pmac_nvram_OF] = -1;
            nvram_partitions[pmac_nvram_XPRAM] = -1;
            nvram_partitions[pmac_nvram_NR] = -1;
            hdr = (struct chrp_header *)buffer;

            offset = 0;
            buffer[16] = 0;
            do {
                  for (i=0;i<16;i++)
                        buffer[i] = ppc_md.nvram_read_val(offset+i);
                  if (!strcmp(hdr->name, "common"))
                        nvram_partitions[pmac_nvram_OF] = offset + 0x10;
                  if (!strcmp(hdr->name, "APL,MacOS75")) {
                        nvram_partitions[pmac_nvram_XPRAM] = offset + 0x10;
                        nvram_partitions[pmac_nvram_NR] = offset + 0x110;
                  }
                  offset += (hdr->len * 0x10);
            } while(offset < NVRAM_SIZE);
      } else {
            nvram_partitions[pmac_nvram_OF] = 0x1800;
            nvram_partitions[pmac_nvram_XPRAM] = 0x1300;
            nvram_partitions[pmac_nvram_NR] = 0x1400;
      }
      DBG("nvram: OF partition at 0x%x\n", nvram_partitions[pmac_nvram_OF]);
      DBG("nvram: XP partition at 0x%x\n", nvram_partitions[pmac_nvram_XPRAM]);
      DBG("nvram: NR partition at 0x%x\n", nvram_partitions[pmac_nvram_NR]);
}

static void core99_nvram_sync(void)
{
      struct core99_header* hdr99;
      unsigned long flags;

      if (!is_core_99 || !nvram_data || !nvram_image)
            return;

      spin_lock_irqsave(&nv_lock, flags);
      if (!memcmp(nvram_image, (u8*)nvram_data + core99_bank*NVRAM_SIZE,
            NVRAM_SIZE))
            goto bail;

      DBG("Updating nvram...\n");

      hdr99 = (struct core99_header*)nvram_image;
      hdr99->generation++;
      hdr99->hdr.signature = CORE99_SIGNATURE;
      hdr99->hdr.cksum = chrp_checksum(&hdr99->hdr);
      hdr99->adler = core99_calc_adler(nvram_image);
      core99_bank = core99_bank ? 0 : 1;
      if (core99_erase_bank)
            if (core99_erase_bank(core99_bank)) {
                  printk("nvram: Error erasing bank %d\n", core99_bank);
                  goto bail;
            }
      if (core99_write_bank)
            if (core99_write_bank(core99_bank, nvram_image))
                  printk("nvram: Error writing bank %d\n", core99_bank);
 bail:
      spin_unlock_irqrestore(&nv_lock, flags);

#ifdef DEBUG
            mdelay(2000);
#endif
}

static int __init core99_nvram_setup(struct device_node *dp, unsigned long addr)
{
      int i;
      u32 gen_bank0, gen_bank1;

      if (nvram_naddrs < 1) {
            printk(KERN_ERR "nvram: no address\n");
            return -EINVAL;
      }
      nvram_image = alloc_bootmem(NVRAM_SIZE);
      if (nvram_image == NULL) {
            printk(KERN_ERR "nvram: can't allocate ram image\n");
            return -ENOMEM;
      }
      nvram_data = ioremap(addr, NVRAM_SIZE*2);
      nvram_naddrs = 1; /* Make sure we get the correct case */

      DBG("nvram: Checking bank 0...\n");

      gen_bank0 = core99_check((u8 *)nvram_data);
      gen_bank1 = core99_check((u8 *)nvram_data + NVRAM_SIZE);
      core99_bank = (gen_bank0 < gen_bank1) ? 1 : 0;

      DBG("nvram: gen0=%d, gen1=%d\n", gen_bank0, gen_bank1);
      DBG("nvram: Active bank is: %d\n", core99_bank);

      for (i=0; i<NVRAM_SIZE; i++)
            nvram_image[i] = nvram_data[i + core99_bank*NVRAM_SIZE];

      ppc_md.nvram_read_val   = core99_nvram_read_byte;
      ppc_md.nvram_write_val  = core99_nvram_write_byte;
      ppc_md.nvram_read = core99_nvram_read;
      ppc_md.nvram_write      = core99_nvram_write;
      ppc_md.nvram_size = core99_nvram_size;
      ppc_md.nvram_sync = core99_nvram_sync;
      ppc_md.machine_shutdown = core99_nvram_sync;
      /* 
       * Maybe we could be smarter here though making an exclusive list
       * of known flash chips is a bit nasty as older OF didn't provide us
       * with a useful "compatible" entry. A solution would be to really
       * identify the chip using flash id commands and base ourselves on
       * a list of known chips IDs
       */
      if (of_device_is_compatible(dp, "amd-0137")) {
            core99_erase_bank = amd_erase_bank;
            core99_write_bank = amd_write_bank;
      } else {
            core99_erase_bank = sm_erase_bank;
            core99_write_bank = sm_write_bank;
      }
      return 0;
}

int __init pmac_nvram_init(void)
{
      struct device_node *dp;
      struct resource r1, r2;
      unsigned int s1 = 0, s2 = 0;
      int err = 0;

      nvram_naddrs = 0;

      dp = of_find_node_by_name(NULL, "nvram");
      if (dp == NULL) {
            printk(KERN_ERR "Can't find NVRAM device\n");
            return -ENODEV;
      }

      /* Try to obtain an address */
      if (of_address_to_resource(dp, 0, &r1) == 0) {
            nvram_naddrs = 1;
            s1 = (r1.end - r1.start) + 1;
            if (of_address_to_resource(dp, 1, &r2) == 0) {
                  nvram_naddrs = 2;
                  s2 = (r2.end - r2.start) + 1;
            }
      }

      is_core_99 = of_device_is_compatible(dp, "nvram,flash");
      if (is_core_99) {
            err = core99_nvram_setup(dp, r1.start);
            goto bail;
      }

#ifdef CONFIG_PPC32
      if (machine_is(chrp) && nvram_naddrs == 1) {
            nvram_data = ioremap(r1.start, s1);
            nvram_mult = 1;
            ppc_md.nvram_read_val   = direct_nvram_read_byte;
            ppc_md.nvram_write_val  = direct_nvram_write_byte;
      } else if (nvram_naddrs == 1) {
            nvram_data = ioremap(r1.start, s1);
            nvram_mult = (s1 + NVRAM_SIZE - 1) / NVRAM_SIZE;
            ppc_md.nvram_read_val   = direct_nvram_read_byte;
            ppc_md.nvram_write_val  = direct_nvram_write_byte;
      } else if (nvram_naddrs == 2) {
            nvram_addr = ioremap(r1.start, s1);
            nvram_data = ioremap(r2.start, s2);
            ppc_md.nvram_read_val   = indirect_nvram_read_byte;
            ppc_md.nvram_write_val  = indirect_nvram_write_byte;
      } else if (nvram_naddrs == 0 && sys_ctrler == SYS_CTRLER_PMU) {
#ifdef CONFIG_ADB_PMU
            nvram_naddrs = -1;
            ppc_md.nvram_read_val   = pmu_nvram_read_byte;
            ppc_md.nvram_write_val  = pmu_nvram_write_byte;
#endif /* CONFIG_ADB_PMU */
      } else {
            printk(KERN_ERR "Incompatible type of NVRAM\n");
            err = -ENXIO;
      }
#endif /* CONFIG_PPC32 */
bail:
      of_node_put(dp);
      if (err == 0)
            lookup_partitions();
      return err;
}

int pmac_get_partition(int partition)
{
      return nvram_partitions[partition];
}

u8 pmac_xpram_read(int xpaddr)
{
      int offset = pmac_get_partition(pmac_nvram_XPRAM);

      if (offset < 0 || xpaddr < 0 || xpaddr > 0x100)
            return 0xff;

      return ppc_md.nvram_read_val(xpaddr + offset);
}

void pmac_xpram_write(int xpaddr, u8 data)
{
      int offset = pmac_get_partition(pmac_nvram_XPRAM);

      if (offset < 0 || xpaddr < 0 || xpaddr > 0x100)
            return;

      ppc_md.nvram_write_val(xpaddr + offset, data);
}

EXPORT_SYMBOL(pmac_get_partition);
EXPORT_SYMBOL(pmac_xpram_read);
EXPORT_SYMBOL(pmac_xpram_write);

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