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/*
* arch/arm/mach-tegra/fuse-cache.c
*
* Interface to kfuses on Tegra 200
*
* Copyright (c) 2010, NVIDIA Corporation.
*
* 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.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <mach/fuse.h>
#include <mach/iomap.h>
#include <ap20/arclk_rst.h>
#include <ap20/arfuse.h>
/* register definition */
#define KFUSE_STATE 0x80
#define KFUSE_STATE_DONE 0x10000
#define KFUSE_STATE_CRCPASS 0x20000
#define KFUSE_KEYADDR 0x88
#define KFUSE_KEYADDR_AUTOINC 0x10000
#define KFUSE_KEYADDR_ADDR(addr) (addr)
#define KFUSE_KEYS 0x8c
#define KFUSE_CACHE_SZ (144 * 4)
static u32 *kfuse_cache;
static int kfuse_cache_isvalid;
/* set start address in auto-increment mode */
static inline void kfuse_set_autoinc_addr(u16 addr)
{
writel(KFUSE_KEYADDR_ADDR(0) | KFUSE_KEYADDR_AUTOINC,
IO_ADDRESS(TEGRA_KFUSE_BASE) + KFUSE_KEYADDR);
}
static inline void kfuse_clock_enable(int e)
{
if (e) {
writel(CLK_RST_CONTROLLER_CLK_ENB_H_SET_0_SET_CLK_ENB_KFUSE_FIELD,
IO_ADDRESS(TEGRA_CLK_RESET_BASE +
CLK_RST_CONTROLLER_CLK_ENB_H_SET_0));
} else {
writel(CLK_RST_CONTROLLER_CLK_ENB_H_CLR_0_CLR_CLK_ENB_KFUSE_FIELD,
IO_ADDRESS(TEGRA_CLK_RESET_BASE +
CLK_RST_CONTROLLER_CLK_ENB_H_CLR_0));
}
}
static void kfuse_wait_ready(void)
{
int retries = 1;
/* wait for hardware to finish loading and verifying key data */
do {
u32 val;
val = readl(IO_ADDRESS(TEGRA_KFUSE_BASE) + KFUSE_STATE);
if ((val & KFUSE_STATE_DONE) == KFUSE_STATE_DONE) {
/* hardware does CRC check */
kfuse_cache_isvalid = (val & KFUSE_STATE_CRCPASS) == KFUSE_STATE_CRCPASS;
break;
}
msleep(10);
} while( --retries >= 0 );
}
static void kfuse_rewind(void)
{
/* force HW to decode and check fuses if it has not already done so */
kfuse_set_autoinc_addr(0);
kfuse_wait_ready();
// kfuse_set_autoinc_addr(0);
}
static inline u32 kfuse_read(void)
{
return readl(IO_ADDRESS(TEGRA_KFUSE_BASE) + KFUSE_KEYS);
}
/* this is called very early in init because there is a bug that can cause
* corruption if DMA and non-DMA requests overlap on APB bus. */
void __init tegra_init_fuse_cache(void) {
unsigned i;
kfuse_cache = kzalloc(KFUSE_CACHE_SZ, GFP_KERNEL);
kfuse_clock_enable(1);
kfuse_rewind();
printk(KERN_DEBUG "kfuse_cache_isvalid=%d\n", kfuse_cache_isvalid);
if (!kfuse_cache_isvalid) {
printk(KERN_ERR "kfuse CRC or ECC error\n");
} else {
/* load if no CRC or ECC errors */
for (i = 0; i < KFUSE_CACHE_SZ / sizeof (u32); i ++)
kfuse_cache[i] = kfuse_read();
}
kfuse_clock_enable(0);
}
const u32 *tegra_kfuse_cache_get(size_t *size) {
if (size) *size = KFUSE_CACHE_SZ;
return kfuse_cache;
}
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