[PATCH 1/8] memory: atmel-sdramc: export a shutdown function

Alexandre Belloni
2014-10-21T21:56:13Z

It is necessary to shutdown the SDRAM before resetting the SoC to avoid having
issue with NAND boot.

Export a function that does exactly that.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
drivers/memory/atmel-sdramc.c | 90 +++++++++++++++++++++++++++++++++++++++++++
include/soc/atmel/memory.h | 6 +++
2 files changed, 96 insertions(+)
create mode 100644 include/soc/atmel/memory.h

diff --git a/drivers/memory/atmel-sdramc.c b/drivers/memory/atmel-sdramc.c
index fed04e8efe75..148906dabe55 100644
--- a/drivers/memory/atmel-sdramc.c
+++ b/drivers/memory/atmel-sdramc.c
@@ -21,24 +21,101 @@
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>

+#include <soc/atmel/memory.h>
+
+#define AT91_SDRAMC_TR 0x04 /* SDRAM Controller Refresh Timer Register */
+#define AT91_SDRAMC_LPR 0x10 /* SDRAM Controller Low Power Register */
+#define AT91_SDRAMC_LPCB_POWER_DOWN 2
+
+#define AT91_DDRSDRC_RTR 0x04 /* Refresh Timer Register */
+#define AT91_DDRSDRC_LPR 0x1C /* Low Power Register */
+#define AT91_DDRSDRC_LPCB_POWER_DOWN 2
+
+static void __iomem *at91_ramc_base[2];
+
+void (*at91_ramc_shutdown)(void);
+
struct at91_ramc_caps {
bool has_ddrck;
bool has_mpddr_clk;
+ void (*shutdown)(void);
};

+void at91sam9260_shutdown(void)
+{
+ pr_err("%s +%d %s\n", __FILE__, __LINE__, __func__);
+ asm volatile(
+ /* Align to cache lines */
+ ".balign 32\n\t"
+
+ /* Disable SDRAM accesses */
+ "str %1, [%0, #" __stringify(AT91_SDRAMC_TR) "]\n\t"
+
+ /* Power down SDRAM */
+ "str %2, [%0, #" __stringify(AT91_SDRAMC_LPR) "]\n\t"
+
+ :
+ : "r" (at91_ramc_base[0]),
+ "r" (1),
+ "r" (AT91_SDRAMC_LPCB_POWER_DOWN));
+}
+
+void at91sam9g45_shutdown(void)
+{
+ 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 %2, [%0, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t"
+ /* Power down SDRAM0 */
+ " str %3, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
+ /* Disable SDRAM1 accesses */
+ " strne %2, [%1, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t"
+ /* Power down SDRAM1 */
+ " strne %3, [%1, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
+
+ :
+ : "r" (at91_ramc_base[0]),
+ "r" (at91_ramc_base[1]),
+ "r" (1),
+ "r" (AT91_DDRSDRC_LPCB_POWER_DOWN)
+ : "r0");
+}
+
static const struct at91_ramc_caps at91rm9200_caps = { };

+static const struct at91_ramc_caps at91sam9260_caps = {
+ .shutdown = at91sam9260_shutdown,
+};
+
static const struct at91_ramc_caps at91sam9g45_caps = {
.has_ddrck = 1,
.has_mpddr_clk = 0,
+ .shutdown = at91sam9g45_shutdown,
};

static const struct at91_ramc_caps sama5d3_caps = {
.has_ddrck = 1,
.has_mpddr_clk = 1,
+ .shutdown = at91sam9g45_shutdown,
};

static const struct of_device_id atmel_ramc_of_match[] = {
@@ -54,7 +131,9 @@ static int atmel_ramc_probe(struct platform_device *pdev)
{
const struct of_device_id *match;
const struct at91_ramc_caps *caps;
+ struct device_node *np;
struct clk *clk;
+ int idx = 0;

match = of_match_device(atmel_ramc_of_match, &pdev->dev);
caps = match->data;
@@ -75,6 +154,17 @@ static int atmel_ramc_probe(struct platform_device *pdev)
clk_prepare_enable(clk);
}

+ for_each_matching_node(np, atmel_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++;
+ }
+
+ at91_ramc_shutdown = caps->shutdown;
+
return 0;
}

diff --git a/include/soc/atmel/memory.h b/include/soc/atmel/memory.h
new file mode 100644
index 000000000000..04cc1261e636
--- /dev/null
+++ b/include/soc/atmel/memory.h
@@ -0,0 +1,6 @@
+#ifndef __INCLUDE_ATMEL_MEMORY_H
+#define __INCLUDE_ATMEL_MEMORY_H
+
+extern void (*at91_ramc_shutdown)(void);
+
+#endif /* __INCLUDE_ATMEL_MEMORY_H */
--
1.9.1