ARM: 5778/1: AT91: Add cpuidle support

This patch adds the support for cpuidle on AT91 SoCs, taken from the
cpuidle support in mach-kirkwood.
cpuidle needs sdram_selfrefresh_enable and _disable, so move their
definition to a separate header file instead of duplicating the code
already used in pm.c.

Tested-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 67 insertions, 0 deletions

diff --git a/arch/arm/mach-at91/pm.h b/arch/arm/mach-at91/pm.h
new file mode 100644
index 000000000000..08322c44df1a
--- /dev/null
+++ b/arch/arm/mach-at91/pm.h
@@ -0,0 +1,67 @@
+#ifdef CONFIG_ARCH_AT91RM9200
+#include <mach/at91rm9200_mc.h>
+
+/*
+ * The AT91RM9200 goes into self-refresh mode with this command, and will
+ * terminate self-refresh automatically on the next SDRAM access.
+ *
+ * Self-refresh mode is exited as soon as a memory access is made, but we don't
+ * know for sure when that happens. However, we need to restore the low-power
+ * mode if it was enabled before going idle. Restoring low-power mode while
+ * still in self-refresh is "not recommended", but seems to work.
+ */
+
+static inline u32 sdram_selfrefresh_enable(void)
+{
+        u32 saved_lpr = at91_sys_read(AT91_SDRAMC_LPR);
+
+        at91_sys_write(AT91_SDRAMC_LPR, 0);
+        at91_sys_write(AT91_SDRAMC_SRR, 1);
+        return saved_lpr;
+}
+
+#define sdram_selfrefresh_disable(saved_lpr)    at91_sys_write(AT91_SDRAMC_LPR, saved_lpr)
+
+#elif defined(CONFIG_ARCH_AT91CAP9)
+#include <mach/at91cap9_ddrsdr.h>
+
+
+static inline u32 sdram_selfrefresh_enable(void)
+{
+        u32 saved_lpr, lpr;
+
+        saved_lpr = at91_sys_read(AT91_DDRSDRC_LPR);
+
+        lpr = saved_lpr & ~AT91_DDRSDRC_LPCB;
+        at91_sys_write(AT91_DDRSDRC_LPR, lpr | AT91_DDRSDRC_LPCB_SELF_REFRESH);
+        return saved_lpr;
+}
+
+#define sdram_selfrefresh_disable(saved_lpr)    at91_sys_write(AT91_DDRSDRC_LPR, saved_lpr)
+
+#else
+#include <mach/at91sam9_sdramc.h>
+
+#ifdef CONFIG_ARCH_AT91SAM9263
+/*
+ * FIXME either or both the SDRAM controllers (EB0, EB1) might be in use;
+ * handle those cases both here and in the Suspend-To-RAM support.
+ */
+#define AT91_SDRAMC     AT91_SDRAMC0
+#warning Assuming EB1 SDRAM controller is *NOT* used
+#endif
+
+static inline u32 sdram_selfrefresh_enable(void)
+{
+        u32 saved_lpr, lpr;
+
+        saved_lpr = at91_sys_read(AT91_SDRAMC_LPR);
+
+        lpr = saved_lpr & ~AT91_SDRAMC_LPCB;
+        at91_sys_write(AT91_SDRAMC_LPR, lpr | AT91_SDRAMC_LPCB_SELF_REFRESH);
+        return saved_lpr;
+}
+
+#define sdram_selfrefresh_disable(saved_lpr)    at91_sys_write(AT91_SDRAMC_LPR, saved_lpr)
+
+#endif