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Diffstat (limited to 'board/w7o/init.S')
| -rw-r--r-- | board/w7o/init.S | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/board/w7o/init.S b/board/w7o/init.S new file mode 100644 index 0000000..0abf21f --- /dev/null +++ b/board/w7o/init.S @@ -0,0 +1,264 @@ +/****************************************************************************** + * + * This source code has been made available to you by IBM on an AS-IS + * basis. Anyone receiving this source is licensed under IBM + * copyrights to use it in any way he or she deems fit, including + * copying it, modifying it, compiling it, and redistributing it either + * with or without modifications. No license under IBM patents or + * patent applications is to be implied by the copyright license. + * + * Any user of this software should understand that IBM cannot provide + * technical support for this software and will not be responsible for + * any consequences resulting from the use of this software. + * + * Any person who transfers this source code or any derivative work + * must include the IBM copyright notice, this paragraph, and the + * preceding two paragraphs in the transferred software. + * + * COPYRIGHT I B M CORPORATION 1995 + * LICENSED MATERIAL - PROGRAM PROPERTY OF I B M + * + *****************************************************************************/ +#include <config.h> +#include <ppc4xx.h> + +#define _LINUX_CONFIG_H 1 /* avoid reading Linux autoconf.h file */ + +#include <ppc_asm.tmpl> +#include <ppc_defs.h> + +#include <asm/cache.h> +#include <asm/mmu.h> + +/****************************************************************************** + * Function: ext_bus_cntlr_init + * + * Description: Configures EBC Controller and a few basic chip selects. + * + * CS0 is setup to get the Boot Flash out of the addresss range + * so that we may setup a stack. CS7 is setup so that we can + * access and reset the hardware watchdog. + * + * IMPORTANT: For pass1 this code must run from + * cache since you can not reliably change a peripheral banks + * timing register (pbxap) while running code from that bank. + * For ex., since we are running from ROM on bank 0, we can NOT + * execute the code that modifies bank 0 timings from ROM, so + * we run it from cache. + * + * Notes: Does NOT use the stack. + *****************************************************************************/ + .section ".text" + .align 2 + .globl ext_bus_cntlr_init + .type ext_bus_cntlr_init, @function +ext_bus_cntlr_init: + mflr r0 + /******************************************************************** + * Prefetch entire ext_bus_cntrl_init function into the icache. + * This is necessary because we are going to change the same CS we + * are executing from. Otherwise a CPU lockup may occur. + *******************************************************************/ + bl ..getAddr +..getAddr: + mflr r3 /* get address of ..getAddr */ + + /* Calculate number of cache lines for this function */ + addi r4, 0, (((.Lfe0 - ..getAddr) / CFG_CACHELINE_SIZE) + 2) + mtctr r4 +..ebcloop: + icbt r0, r3 /* prefetch cache line for addr in r3*/ + addi r3, r3, CFG_CACHELINE_SIZE /* move to next cache line */ + bdnz ..ebcloop /* continue for $CTR cache lines */ + + /******************************************************************** + * Delay to ensure all accesses to ROM are complete before changing + * bank 0 timings. 200usec should be enough. + * 200,000,000 (cycles/sec) X .000200 (sec) = 0x9C40 cycles. + *******************************************************************/ + addis r3, 0, 0x0 + ori r3, r3, 0xA000 /* wait 200us from reset */ + mtctr r3 +..spinlp: + bdnz ..spinlp /* spin loop */ + + /******************************************************************** + * Setup External Bus Controller (EBC). + *******************************************************************/ + addi r3, 0, epcr + mtdcr ebccfga, r3 + addis r4, 0, 0xb040 /* Device base timeout = 1024 cycles */ + ori r4, r4, 0x0 /* Drive CS with external master */ + mtdcr ebccfgd, r4 + + /******************************************************************** + * Change PCIINT signal to PerWE + *******************************************************************/ + mfdcr r4, cntrl1 + ori r4, r4, 0x4000 + mtdcr cntrl1, r4 + + /******************************************************************** + * Memory Bank 0 (Flash Bank 0) initialization + *******************************************************************/ + addi r3, 0, pb0ap + mtdcr ebccfga, r3 + addis r4, 0, CFG_W7O_EBC_PB0AP@h + ori r4, r4, CFG_W7O_EBC_PB0AP@l + mtdcr ebccfgd, r4 + + addi r3, 0, pb0cr + mtdcr ebccfga, r3 + addis r4, 0, CFG_W7O_EBC_PB0CR@h + ori r4, r4, CFG_W7O_EBC_PB0CR@l + mtdcr ebccfgd, r4 + + /******************************************************************** + * Memory Bank 7 LEDs - NEEDED BECAUSE OF HW WATCHDOG AND LEDs. + *******************************************************************/ + addi r3, 0, pb7ap + mtdcr ebccfga, r3 + addis r4, 0, CFG_W7O_EBC_PB7AP@h + ori r4, r4, CFG_W7O_EBC_PB7AP@l + mtdcr ebccfgd, r4 + + addi r3, 0, pb7cr + mtdcr ebccfga, r3 + addis r4, 0, CFG_W7O_EBC_PB7CR@h + ori r4, r4, CFG_W7O_EBC_PB7CR@l + mtdcr ebccfgd, r4 + + /* We are all done */ + mtlr r0 /* Restore link register */ + blr /* Return to calling function */ +.Lfe0: .size ext_bus_cntlr_init,.Lfe0-ext_bus_cntlr_init +/* end ext_bus_cntlr_init() */ + +/****************************************************************************** + * Function: sdram_init + * + * Description: Configures SDRAM memory banks. + * + * Serial Presence Detect, "SPD," reads the SDRAM EEPROM + * via the IIC bus and then configures the SDRAM memory + * banks appropriately. If Auto Memory Configuration is + * is not used, it is assumed that a 4MB 11x8x2, non-ECC, + * SDRAM is soldered down. + * + * Notes: Expects that the stack is already setup. + *****************************************************************************/ + .section ".text" + .align 2 + .globl sdram_init + .type sdram_init, @function +sdram_init: + /* save the return info on stack */ + mflr r0 /* Get link register */ + stwu r1, -8(r1) /* Save back chain and move SP */ + stw r0, +12(r1) /* Save link register */ + + /* + * First call spd_sdram to try to init SDRAM according to the + * contents of the SPD EEPROM. If the SPD EEPROM is blank or + * erronious, spd_sdram returns 0 in R3. + */ + bl spd_sdram + addic. r3, r3, 0 /* Check for error, save dram size */ + bne ..sdri_done /* If it worked, we're done... */ + + /******************************************************************** + * If SPD detection fails, we'll default to 4MB, 11x8x2, as this + * is the SMALLEST SDRAM size the 405 supports. We can do this + * because W7O boards have soldered on RAM, and there will always + * be some amount present. If we were using DIMMs, we should hang + * the board instead, since it doesn't have any RAM to continue + * running with. + *******************************************************************/ + + /* + * Disable memory controller to allow + * values to be changed. + */ + addi r3, 0, mem_mcopt1 + mtdcr memcfga, r3 + addis r4, 0, 0x0 + ori r4, r4, 0x0 + mtdcr memcfgd, r4 + + /* + * Set MB0CF for ext bank 0. (0-4MB) Address Mode 5 since 11x8x2 + * All other banks are disabled. + */ + addi r3, 0, mem_mb0cf + mtdcr memcfga, r3 + addis r4, 0, 0x0000 /* BA=0x0, SZ=4MB */ + ori r4, r4, 0x8001 /* Mode is 5, 11x8x2or4, BE=Enabled */ + mtdcr memcfgd, r4 + + /* Clear MB1CR,MB2CR,MB3CR to turn other banks off */ + addi r4, 0, 0 /* Zero the data reg */ + + addi r3, r3, 4 /* Point to MB1CF reg */ + mtdcr memcfga, r3 /* Set the address */ + mtdcr memcfgd, r4 /* Zero the reg */ + + addi r3, r3, 4 /* Point to MB2CF reg */ + mtdcr memcfga, r3 /* Set the address */ + mtdcr memcfgd, r4 /* Zero the reg */ + + addi r3, r3, 4 /* Point to MB3CF reg */ + mtdcr memcfga, r3 /* Set the address */ + mtdcr memcfgd, r4 /* Zero the reg */ + + /******************************************************************** + * Set the SDRAM Timing reg, SDTR1 and the refresh timer reg, RTR. + * To set the appropriate timings, we assume sdram is + * 100MHz (pc100 compliant). + *******************************************************************/ + + /* + * Set up SDTR1 + */ + addi r3, 0, mem_sdtr1 + mtdcr memcfga, r3 + addis r4, 0, 0x0086 /* SDTR1 value for 100Mhz */ + ori r4, r4, 0x400D + mtdcr memcfgd, r4 + + /* + * Set RTR + */ + addi r3, 0, mem_rtr + mtdcr memcfga, r3 + addis r4, 0, 0x05F0 /* RTR refresh val = 15.625ms@100Mhz */ + mtdcr memcfgd, r4 + + /******************************************************************** + * Delay to ensure 200usec have elapsed since reset. Assume worst + * case that the core is running 200Mhz: + * 200,000,000 (cycles/sec) X .000200 (sec) = 0x9C40 cycles + *******************************************************************/ + addis r3, 0, 0x0000 + ori r3, r3, 0xA000 /* Wait 200us from reset */ + mtctr r3 +..spinlp2: + bdnz ..spinlp2 /* spin loop */ + + /******************************************************************** + * Set memory controller options reg, MCOPT1. + *******************************************************************/ + addi r3, 0, mem_mcopt1 + mtdcr memcfga, r3 + addis r4, 0, 0x80E0 /* DC_EN=1,SRE=0,PME=0,MEMCHK=0 */ + ori r4, r4, 0x0000 /* REGEN=0,DRW=00,BRPF=01,ECCDD=1 */ + mtdcr memcfgd, r4 /* EMDULR=1 */ + +..sdri_done: + /* restore and return */ + lwz r0, +12(r1) /* Get saved link register */ + addi r1, r1, +8 /* Remove frame from stack */ + mtlr r0 /* Restore link register */ + blr /* Return to calling function */ +.Lfe1: .size sdram_init,.Lfe1-sdram_init +/* end sdram_init() */ + |