[PATCH] icecube/lite5200b: wakeup from low-power support
U-Boot part of Lite5200b low power mode support.
Puts SDRAM out of self-refresh and transfers control to
address saved at physical 0x0.
Signed-off-by: Domen Puncer <domen.puncer@telargo.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/board/icecube/icecube.c b/board/icecube/icecube.c
index 700c9d9..2960998 100644
--- a/board/icecube/icecube.c
+++ b/board/icecube/icecube.c
@@ -42,6 +42,53 @@
#include "mt48lc16m16a2-75.h"
# endif
#endif
+
+#ifdef CONFIG_LITE5200B_PM
+/* u-boot part of low-power mode implementation */
+#define SAVED_ADDR (*(void **)0x00000000)
+#define PSC2_4 0x02
+
+void lite5200b_wakeup(void)
+{
+ unsigned char wakeup_pin;
+ void (*linux_wakeup)(void);
+
+ /* check PSC2_4, if it's down "QT" is signaling we have a wakeup
+ * from low power mode */
+ *(vu_char *)MPC5XXX_WU_GPIO_ENABLE = PSC2_4;
+ __asm__ volatile ("sync");
+
+ wakeup_pin = *(vu_char *)MPC5XXX_WU_GPIO_DATA_I;
+ if (wakeup_pin & PSC2_4)
+ return;
+
+ /* acknowledge to "QT"
+ * by holding pin at 1 for 10 uS */
+ *(vu_char *)MPC5XXX_WU_GPIO_DIR = PSC2_4;
+ __asm__ volatile ("sync");
+ *(vu_char *)MPC5XXX_WU_GPIO_DATA_O = PSC2_4;
+ __asm__ volatile ("sync");
+ udelay(10);
+
+ /* put ram out of self-refresh */
+ *(vu_long *)MPC5XXX_SDRAM_CTRL |= 0x80000000; /* mode_en */
+ __asm__ volatile ("sync");
+ *(vu_long *)MPC5XXX_SDRAM_CTRL |= 0x50000000; /* cke ref_en */
+ __asm__ volatile ("sync");
+ *(vu_long *)MPC5XXX_SDRAM_CTRL &= ~0x80000000; /* !mode_en */
+ __asm__ volatile ("sync");
+ udelay(10); /* wait a bit */
+
+ /* jump back to linux kernel code */
+ linux_wakeup = SAVED_ADDR;
+ printf("\n\nLooks like we just woke, transferring control to 0x%08lx\n",
+ linux_wakeup);
+ linux_wakeup();
+}
+#else
+#define lite5200b_wakeup()
+#endif
+
#ifndef CFG_RAMBOOT
static void sdram_start (int hi_addr)
{
@@ -208,6 +255,8 @@
__asm__ volatile ("sync");
}
+ lite5200b_wakeup();
+
return dramsize + dramsize2;
}