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authorAlexandre Belloni <alexandre.belloni@free-electrons.com>2016-10-25 11:37:59 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-03-12 06:41:45 +0100
commit206af3d97f00d5c96de5bfd5a48045d444b3eec4 (patch)
tree6ed7ffb19b51fbbe2e5c7f9b70e511718c95ac8f /drivers/power
parente9dc8334d765f7910114921c63a0324272f1f636 (diff)
power: reset: at91-poweroff: timely shutdown LPDDR memories
commit 0b0408745e7ff24757cbfd571d69026c0ddb803c upstream. LPDDR memories can only handle up to 400 uncontrolled power off. Ensure the proper power off sequence is used before shutting down the platform. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Sebastian Reichel <sre@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/power')
-rw-r--r--drivers/power/reset/Kconfig2
-rw-r--r--drivers/power/reset/at91-poweroff.c54
-rw-r--r--drivers/power/reset/at91-sama5d2_shdwc.c49
3 files changed, 102 insertions, 3 deletions
diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index c74c3f67b8da..02e46bbcf45d 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -32,7 +32,7 @@ config POWER_RESET_AT91_RESET
config POWER_RESET_AT91_SAMA5D2_SHDWC
tristate "Atmel AT91 SAMA5D2-Compatible shutdown controller driver"
- depends on ARCH_AT91 || COMPILE_TEST
+ depends on ARCH_AT91
default SOC_SAMA5
help
This driver supports the alternate shutdown controller for some Atmel
diff --git a/drivers/power/reset/at91-poweroff.c b/drivers/power/reset/at91-poweroff.c
index e9e24df35f26..2579f025b90b 100644
--- a/drivers/power/reset/at91-poweroff.c
+++ b/drivers/power/reset/at91-poweroff.c
@@ -14,9 +14,12 @@
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/printk.h>
+#include <soc/at91/at91sam9_ddrsdr.h>
+
#define AT91_SHDW_CR 0x00 /* Shut Down Control Register */
#define AT91_SHDW_SHDW BIT(0) /* Shut Down command */
#define AT91_SHDW_KEY (0xa5 << 24) /* KEY Password */
@@ -50,6 +53,7 @@ static const char *shdwc_wakeup_modes[] = {
static void __iomem *at91_shdwc_base;
static struct clk *sclk;
+static void __iomem *mpddrc_base;
static void __init at91_wakeup_status(void)
{
@@ -73,6 +77,29 @@ static void at91_poweroff(void)
writel(AT91_SHDW_KEY | AT91_SHDW_SHDW, at91_shdwc_base + AT91_SHDW_CR);
}
+static void at91_lpddr_poweroff(void)
+{
+ asm volatile(
+ /* Align to cache lines */
+ ".balign 32\n\t"
+
+ /* Ensure AT91_SHDW_CR is in the TLB by reading it */
+ " ldr r6, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
+
+ /* Power down SDRAM0 */
+ " str %1, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
+ /* Shutdown CPU */
+ " str %3, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
+
+ " b .\n\t"
+ :
+ : "r" (mpddrc_base),
+ "r" cpu_to_le32(AT91_DDRSDRC_LPDDR2_PWOFF),
+ "r" (at91_shdwc_base),
+ "r" cpu_to_le32(AT91_SHDW_KEY | AT91_SHDW_SHDW)
+ : "r0");
+}
+
static int at91_poweroff_get_wakeup_mode(struct device_node *np)
{
const char *pm;
@@ -124,6 +151,8 @@ static void at91_poweroff_dt_set_wakeup_mode(struct platform_device *pdev)
static int __init at91_poweroff_probe(struct platform_device *pdev)
{
struct resource *res;
+ struct device_node *np;
+ u32 ddr_type;
int ret;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -150,12 +179,30 @@ static int __init at91_poweroff_probe(struct platform_device *pdev)
pm_power_off = at91_poweroff;
+ np = of_find_compatible_node(NULL, NULL, "atmel,sama5d3-ddramc");
+ if (!np)
+ return 0;
+
+ mpddrc_base = of_iomap(np, 0);
+ of_node_put(np);
+
+ if (!mpddrc_base)
+ return 0;
+
+ ddr_type = readl(mpddrc_base + AT91_DDRSDRC_MDR) & AT91_DDRSDRC_MD;
+ if ((ddr_type == AT91_DDRSDRC_MD_LPDDR2) ||
+ (ddr_type == AT91_DDRSDRC_MD_LPDDR3))
+ pm_power_off = at91_lpddr_poweroff;
+ else
+ iounmap(mpddrc_base);
+
return 0;
}
static int __exit at91_poweroff_remove(struct platform_device *pdev)
{
- if (pm_power_off == at91_poweroff)
+ if (pm_power_off == at91_poweroff ||
+ pm_power_off == at91_lpddr_poweroff)
pm_power_off = NULL;
clk_disable_unprepare(sclk);
@@ -163,6 +210,11 @@ static int __exit at91_poweroff_remove(struct platform_device *pdev)
return 0;
}
+static const struct of_device_id at91_ramc_of_match[] = {
+ { .compatible = "atmel,sama5d3-ddramc", },
+ { /* sentinel */ }
+};
+
static const struct of_device_id at91_poweroff_of_match[] = {
{ .compatible = "atmel,at91sam9260-shdwc", },
{ .compatible = "atmel,at91sam9rl-shdwc", },
diff --git a/drivers/power/reset/at91-sama5d2_shdwc.c b/drivers/power/reset/at91-sama5d2_shdwc.c
index 8a5ac9706c9c..90b0b5a70ce5 100644
--- a/drivers/power/reset/at91-sama5d2_shdwc.c
+++ b/drivers/power/reset/at91-sama5d2_shdwc.c
@@ -22,9 +22,12 @@
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/printk.h>
+#include <soc/at91/at91sam9_ddrsdr.h>
+
#define SLOW_CLOCK_FREQ 32768
#define AT91_SHDW_CR 0x00 /* Shut Down Control Register */
@@ -75,6 +78,7 @@ struct shdwc {
*/
static struct shdwc *at91_shdwc;
static struct clk *sclk;
+static void __iomem *mpddrc_base;
static const unsigned long long sdwc_dbc_period[] = {
0, 3, 32, 512, 4096, 32768,
@@ -108,6 +112,29 @@ static void at91_poweroff(void)
at91_shdwc->at91_shdwc_base + AT91_SHDW_CR);
}
+static void at91_lpddr_poweroff(void)
+{
+ asm volatile(
+ /* Align to cache lines */
+ ".balign 32\n\t"
+
+ /* Ensure AT91_SHDW_CR is in the TLB by reading it */
+ " ldr r6, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
+
+ /* Power down SDRAM0 */
+ " str %1, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
+ /* Shutdown CPU */
+ " str %3, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
+
+ " b .\n\t"
+ :
+ : "r" (mpddrc_base),
+ "r" cpu_to_le32(AT91_DDRSDRC_LPDDR2_PWOFF),
+ "r" (at91_shdwc->at91_shdwc_base),
+ "r" cpu_to_le32(AT91_SHDW_KEY | AT91_SHDW_SHDW)
+ : "r0");
+}
+
static u32 at91_shdwc_debouncer_value(struct platform_device *pdev,
u32 in_period_us)
{
@@ -212,6 +239,8 @@ static int __init at91_shdwc_probe(struct platform_device *pdev)
{
struct resource *res;
const struct of_device_id *match;
+ struct device_node *np;
+ u32 ddr_type;
int ret;
if (!pdev->dev.of_node)
@@ -249,6 +278,23 @@ static int __init at91_shdwc_probe(struct platform_device *pdev)
pm_power_off = at91_poweroff;
+ np = of_find_compatible_node(NULL, NULL, "atmel,sama5d3-ddramc");
+ if (!np)
+ return 0;
+
+ mpddrc_base = of_iomap(np, 0);
+ of_node_put(np);
+
+ if (!mpddrc_base)
+ return 0;
+
+ ddr_type = readl(mpddrc_base + AT91_DDRSDRC_MDR) & AT91_DDRSDRC_MD;
+ if ((ddr_type == AT91_DDRSDRC_MD_LPDDR2) ||
+ (ddr_type == AT91_DDRSDRC_MD_LPDDR3))
+ pm_power_off = at91_lpddr_poweroff;
+ else
+ iounmap(mpddrc_base);
+
return 0;
}
@@ -256,7 +302,8 @@ static int __exit at91_shdwc_remove(struct platform_device *pdev)
{
struct shdwc *shdw = platform_get_drvdata(pdev);
- if (pm_power_off == at91_poweroff)
+ if (pm_power_off == at91_poweroff ||
+ pm_power_off == at91_lpddr_poweroff)
pm_power_off = NULL;
/* Reset values to disable wake-up features */