Puts SDRAM out of self-refresh and transfers control to address saved at physical 0x0.
Used by Linux patches posted at http://ozlabs.org/pipermail/linuxppc-embedded/2007-March/026242.html
Index: u-boot-of.git/board/icecube/icecube.c =================================================================== --- u-boot-of.git.orig/board/icecube/icecube.c +++ u-boot-of.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 = 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; }
Index: u-boot-of.git/include/mpc5xxx.h =================================================================== --- u-boot-of.git.orig/include/mpc5xxx.h +++ u-boot-of.git/include/mpc5xxx.h @@ -189,6 +189,7 @@ #define MPC5XXX_WU_GPIO_ODE (MPC5XXX_WU_GPIO + 0x0004) #define MPC5XXX_WU_GPIO_DIR (MPC5XXX_WU_GPIO + 0x0008) #define MPC5XXX_WU_GPIO_DATA (MPC5XXX_WU_GPIO + 0x000c) +#define MPC5XXX_WU_GPIO_DATA_I (MPC5XXX_WU_GPIO + 0x0020)
/* PCI registers */ #define MPC5XXX_PCI_CMD (MPC5XXX_PCI + 0x04)