From 05ab8bdb813acdcd74afa71d6656c2df816cb230 Mon Sep 17 00:00:00 2001 From: Luca Ellero Date: Wed, 9 Feb 2011 20:36:14 +0000 Subject: cortex_a9: implement read/write memory through APB-AP This patch adds read/write capability to memory addresses not accessible through AHB-AP (for example "boot ROM code"). To select AHB or APB, a "dap apsel" command must be issued: dap apsel 0 -> following memory accesses are through AHB dap apsel 1 -> following memory accesses are through APB NOTE: at the moment APB memory accesses are very slow, compared to AHB accesses. Work has to be done to get it faster (for example LDR/STR instead od LDRB/STRB) Signed-off-by: Luca Ellero --- src/target/cortex_a9.c | 160 +++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 129 insertions(+), 31 deletions(-) (limited to 'src/target') diff --git a/src/target/cortex_a9.c b/src/target/cortex_a9.c index 62bf2630..e4113351 100644 --- a/src/target/cortex_a9.c +++ b/src/target/cortex_a9.c @@ -1492,29 +1492,76 @@ static int cortex_a9_read_phys_memory(struct target *target, struct armv7a_common *armv7a = target_to_armv7a(target); struct adiv5_dap *swjdp = &armv7a->dap; int retval = ERROR_INVALID_ARGUMENTS; - uint8_t saved_apsel = dap_ap_get_select(swjdp); - - /* cortex_a9 handles unaligned memory access */ - - dap_ap_select(swjdp, swjdp_memoryap); + uint8_t apsel = dap_ap_get_select(swjdp); LOG_DEBUG("Reading memory at real address 0x%x; size %d; count %d", address, size, count); + if (count && buffer) { - switch (size) { - case 4: - retval = mem_ap_read_buf_u32(swjdp, buffer, 4 * count, address); - break; - case 2: - retval = mem_ap_read_buf_u16(swjdp, buffer, 2 * count, address); - break; - case 1: - retval = mem_ap_read_buf_u8(swjdp, buffer, count, address); - break; + + if ( apsel == 0) { + /* read memory throug AHB-AP */ + + switch (size) { + case 4: + retval = mem_ap_read_buf_u32(swjdp, buffer, 4 * count, address); + break; + case 2: + retval = mem_ap_read_buf_u16(swjdp, buffer, 2 * count, address); + break; + case 1: + retval = mem_ap_read_buf_u8(swjdp, buffer, count, address); + break; + } + + } else { + + /* read memory throug APB-AP */ + + uint32_t saved_r0, saved_r1; + int nbytes = count * size; + uint32_t data; + + /* save registers r0 and r1, we are going to corrupt them */ + retval = cortex_a9_dap_read_coreregister_u32(target, &saved_r0, 0); + if (retval != ERROR_OK) + return retval; + + retval = cortex_a9_dap_read_coreregister_u32(target, &saved_r1, 1); + if (retval != ERROR_OK) + return retval; + + retval = cortex_a9_dap_write_coreregister_u32(target, address, 0); + if (retval != ERROR_OK) + return retval; + + while (nbytes > 0) { + + /* execute instruction LDRB r1, [r0], 1 (0xe4d01001) */ + retval = cortex_a9_exec_opcode(target, ARMV4_5_LDRB_IP(1, 0) , NULL); + if (retval != ERROR_OK) + return retval; + + retval = cortex_a9_dap_read_coreregister_u32(target, &data, 1); + if (retval != ERROR_OK) + return retval; + + *buffer++ = data; + --nbytes; + + } + + /* restore corrupted registers r0 and r1 */ + retval = cortex_a9_dap_write_coreregister_u32(target, saved_r0, 0); + if (retval != ERROR_OK) + return retval; + + retval = cortex_a9_dap_write_coreregister_u32(target, saved_r1, 1); + if (retval != ERROR_OK) + return retval; + } } - dap_ap_select(swjdp, saved_apsel); - return retval; } @@ -1557,22 +1604,73 @@ static int cortex_a9_write_phys_memory(struct target *target, LOG_DEBUG("Writing memory to real address 0x%x; size %d; count %d", address, size, count); if (count && buffer) { - uint8_t saved_apsel = dap_ap_get_select(swjdp); - dap_ap_select(swjdp, swjdp_memoryap); + uint8_t apsel = dap_ap_get_select(swjdp); + + if ( apsel == 0 ) { + + /* write memory throug AHB-AP */ + switch (size) { + case 4: + retval = mem_ap_write_buf_u32(swjdp, buffer, 4 * count, address); + break; + case 2: + retval = mem_ap_write_buf_u16(swjdp, buffer, 2 * count, address); + break; + case 1: + retval = mem_ap_write_buf_u8(swjdp, buffer, count, address); + break; + } - switch (size) { - case 4: - retval = mem_ap_write_buf_u32(swjdp, buffer, 4 * count, address); - break; - case 2: - retval = mem_ap_write_buf_u16(swjdp, buffer, 2 * count, address); - break; - case 1: - retval = mem_ap_write_buf_u8(swjdp, buffer, count, address); - break; - } + } else { - dap_ap_select(swjdp, saved_apsel); + /* read memory throug APB-AP */ + + uint32_t saved_r0, saved_r1; + int nbytes = count * size; + uint32_t data; + + /* save registers r0 and r1, we are going to corrupt them */ + retval = cortex_a9_dap_read_coreregister_u32(target, &saved_r0, 0); + if (retval != ERROR_OK) + return retval; + + retval = cortex_a9_dap_read_coreregister_u32(target, &saved_r1, 1); + if (retval != ERROR_OK) + return retval; + + retval = cortex_a9_dap_write_coreregister_u32(target, address, 0); + if (retval != ERROR_OK) + return retval; + + while (nbytes > 0) { + + data = *buffer++; + + retval = cortex_a9_dap_write_coreregister_u32(target, data, 1); + if (retval != ERROR_OK) + return retval; + + /* execute instruction STRB r1, [r0], 1 (0xe4c01001) */ + retval = cortex_a9_exec_opcode(target, ARMV4_5_STRB_IP(1, 0) , NULL); + if (retval != ERROR_OK) + return retval; + + --nbytes; + } + + /* restore corrupted registers r0 and r1 */ + retval = cortex_a9_dap_write_coreregister_u32(target, saved_r0, 0); + if (retval != ERROR_OK) + return retval; + + retval = cortex_a9_dap_write_coreregister_u32(target, saved_r1, 1); + if (retval != ERROR_OK) + return retval; + + /* we can return here without invalidating D/I-cache because */ + /* access through APB maintains cache coherency */ + return retval; + } } -- cgit v1.2.3