U-Boot part of Lite5200b low power mode support.
Puts SDRAM out of self-refresh and transfers control to
address saved at physical 0x0.
---
board/icecube/icecube.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 50 insertions(+)
Index: u-boot.git/board/icecube/icecube.c
===================================================================
--- u-boot.git.orig/board/icecube/icecube.c
+++ u-boot.git/board/icecube/icecube.c
@@ -42,6 +42,54 @@
#include "mt48lc16m16a2-75.h"
# endif
#endif
+
+#ifdef CONFIG_LITE5200B
+/* 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 +256,8 @@ long int initdram (int board_type)
__asm__ volatile ("sync");
}
+ lite5200b_wakeup();
+
return dramsize + dramsize2;
}
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