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/*
* Atmel AT91 SAM9 & SAMA5 SoCs reset code
*
* Copyright (C) 2007 Atmel Corporation.
* Copyright (C) BitBox Ltd 2010
* Copyright (C) 2011 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcosoft.com>
* Copyright (C) 2014 Free Electrons
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <soc/at91/at91sam9_ddrsdr.h>
#include <soc/at91/at91sam9_sdramc.h>
#define AT91_RSTC_CR 0x00 /* Reset Controller Control Register */
#define AT91_RSTC_PROCRST BIT(0) /* Processor Reset */
#define AT91_RSTC_PERRST BIT(2) /* Peripheral Reset */
#define AT91_RSTC_EXTRST BIT(3) /* External Reset */
#define AT91_RSTC_KEY (0xa5 << 24) /* KEY Password */
#define AT91_RSTC_SR 0x04 /* Reset Controller Status Register */
#define AT91_RSTC_URSTS BIT(0) /* User Reset Status */
#define AT91_RSTC_RSTTYP GENMASK(10, 8) /* Reset Type */
#define AT91_RSTC_NRSTL BIT(16) /* NRST Pin Level */
#define AT91_RSTC_SRCMP BIT(17) /* Software Reset Command in Progress */
#define AT91_RSTC_MR 0x08 /* Reset Controller Mode Register */
#define AT91_RSTC_URSTEN BIT(0) /* User Reset Enable */
#define AT91_RSTC_URSTIEN BIT(4) /* User Reset Interrupt Enable */
#define AT91_RSTC_ERSTL GENMASK(11, 8) /* External Reset Length */
enum reset_type {
RESET_TYPE_GENERAL = 0,
RESET_TYPE_WAKEUP = 1,
RESET_TYPE_WATCHDOG = 2,
RESET_TYPE_SOFTWARE = 3,
RESET_TYPE_USER = 4,
};
static void __iomem *at91_ramc_base[2], *at91_rstc_base;
static struct clk *sclk;
/*
* unless the SDRAM is cleanly shutdown before we hit the
* reset register it can be left driving the data bus and
* killing the chance of a subsequent boot from NAND
*/
static int at91sam9260_restart(struct notifier_block *this, unsigned long mode,
void *cmd)
{
asm volatile(
/* Align to cache lines */
".balign 32\n\t"
/* Disable SDRAM accesses */
"str %2, [%0, #" __stringify(AT91_SDRAMC_TR) "]\n\t"
/* Power down SDRAM */
"str %3, [%0, #" __stringify(AT91_SDRAMC_LPR) "]\n\t"
/* Reset CPU */
"str %4, [%1, #" __stringify(AT91_RSTC_CR) "]\n\t"
"b .\n\t"
:
: "r" (at91_ramc_base[0]),
"r" (at91_rstc_base),
"r" (1),
"r" cpu_to_le32(AT91_SDRAMC_LPCB_POWER_DOWN),
"r" cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST));
return NOTIFY_DONE;
}
static int at91sam9g45_restart(struct notifier_block *this, unsigned long mode,
void *cmd)
{
asm volatile(
/*
* Test wether we have a second RAM controller to care
* about.
*
* First, test that we can dereference the virtual address.
*/
"cmp %1, #0\n\t"
"beq 1f\n\t"
/* Then, test that the RAM controller is enabled */
"ldr r0, [%1]\n\t"
"cmp r0, #0\n\t"
/* Align to cache lines */
".balign 32\n\t"
/* Disable SDRAM0 accesses */
"1: str %3, [%0, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t"
/* Power down SDRAM0 */
" str %4, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
/* Disable SDRAM1 accesses */
" strne %3, [%1, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t"
/* Power down SDRAM1 */
" strne %4, [%1, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
/* Reset CPU */
" str %5, [%2, #" __stringify(AT91_RSTC_CR) "]\n\t"
" b .\n\t"
:
: "r" (at91_ramc_base[0]),
"r" (at91_ramc_base[1]),
"r" (at91_rstc_base),
"r" (1),
"r" cpu_to_le32(AT91_DDRSDRC_LPCB_POWER_DOWN),
"r" cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST)
: "r0");
return NOTIFY_DONE;
}
static int sama5d3_restart(struct notifier_block *this, unsigned long mode,
void *cmd)
{
writel(cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST),
at91_rstc_base);
return NOTIFY_DONE;
}
static void __init at91_reset_status(struct platform_device *pdev)
{
u32 reg = readl(at91_rstc_base + AT91_RSTC_SR);
char *reason;
switch ((reg & AT91_RSTC_RSTTYP) >> 8) {
case RESET_TYPE_GENERAL:
reason = "general reset";
break;
case RESET_TYPE_WAKEUP:
reason = "wakeup";
break;
case RESET_TYPE_WATCHDOG:
reason = "watchdog reset";
break;
case RESET_TYPE_SOFTWARE:
reason = "software reset";
break;
case RESET_TYPE_USER:
reason = "user reset";
break;
default:
reason = "unknown reset";
break;
}
pr_info("AT91: Starting after %s\n", reason);
}
static const struct of_device_id at91_ramc_of_match[] = {
{ .compatible = "atmel,at91sam9260-sdramc", },
{ .compatible = "atmel,at91sam9g45-ddramc", },
{ /* sentinel */ }
};
static const struct of_device_id at91_reset_of_match[] = {
{ .compatible = "atmel,at91sam9260-rstc", .data = at91sam9260_restart },
{ .compatible = "atmel,at91sam9g45-rstc", .data = at91sam9g45_restart },
{ .compatible = "atmel,sama5d3-rstc", .data = sama5d3_restart },
{ /* sentinel */ }
};
static struct notifier_block at91_restart_nb = {
.priority = 192,
};
static int __init at91_reset_probe(struct platform_device *pdev)
{
const struct of_device_id *match;
struct device_node *np;
int ret, idx = 0;
at91_rstc_base = of_iomap(pdev->dev.of_node, 0);
if (!at91_rstc_base) {
dev_err(&pdev->dev, "Could not map reset controller address\n");
return -ENODEV;
}
if (!of_device_is_compatible(pdev->dev.of_node, "atmel,sama5d3-rstc")) {
/* we need to shutdown the ddr controller, so get ramc base */
for_each_matching_node(np, at91_ramc_of_match) {
at91_ramc_base[idx] = of_iomap(np, 0);
if (!at91_ramc_base[idx]) {
dev_err(&pdev->dev, "Could not map ram controller address\n");
return -ENODEV;
}
idx++;
}
}
match = of_match_node(at91_reset_of_match, pdev->dev.of_node);
at91_restart_nb.notifier_call = match->data;
sclk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(sclk))
return PTR_ERR(sclk);
ret = clk_prepare_enable(sclk);
if (ret) {
dev_err(&pdev->dev, "Could not enable slow clock\n");
return ret;
}
ret = register_restart_handler(&at91_restart_nb);
if (ret) {
clk_disable_unprepare(sclk);
return ret;
}
at91_reset_status(pdev);
return 0;
}
static int __exit at91_reset_remove(struct platform_device *pdev)
{
unregister_restart_handler(&at91_restart_nb);
clk_disable_unprepare(sclk);
return 0;
}
static const struct platform_device_id at91_reset_plat_match[] = {
{ "at91-sam9260-reset", (unsigned long)at91sam9260_restart },
{ "at91-sam9g45-reset", (unsigned long)at91sam9g45_restart },
{ /* sentinel */ }
};
static struct platform_driver at91_reset_driver = {
.remove = __exit_p(at91_reset_remove),
.driver = {
.name = "at91-reset",
.of_match_table = at91_reset_of_match,
},
.id_table = at91_reset_plat_match,
};
module_platform_driver_probe(at91_reset_driver, at91_reset_probe);
MODULE_AUTHOR("Atmel Corporation");
MODULE_DESCRIPTION("Reset driver for Atmel SoCs");
MODULE_LICENSE("GPL v2");
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