diff options
Diffstat (limited to 'contrib/loaders/flash/stm32/stm32h7x.S')
| -rw-r--r-- | contrib/loaders/flash/stm32/stm32h7x.S | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/contrib/loaders/flash/stm32/stm32h7x.S b/contrib/loaders/flash/stm32/stm32h7x.S new file mode 100644 index 0000000..f910bfb --- /dev/null +++ b/contrib/loaders/flash/stm32/stm32h7x.S @@ -0,0 +1,108 @@ +/*************************************************************************** + * Copyright (C) 2017 by STMicroelectronics * + * * + * This program is free software; you can redistribute it and/or modify * + * it under the terms of the GNU General Public License as published by * + * the Free Software Foundation; either version 2 of the License, or * + * (at your option) any later version. * + * * + * This program is distributed in the hope that it will be useful, * + * but WITHOUT ANY WARRANTY; without even the implied warranty of * + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * + * GNU General Public License for more details. * + * * + * You should have received a copy of the GNU General Public License * + * along with this program; if not, write to the * + * Free Software Foundation, Inc. * + ***************************************************************************/ + + .text + .syntax unified + .cpu cortex-m7 + .thumb + +/* + * Code limitations: + * The workarea must have size multiple of 4 bytes, since R/W + * operations are all at 32 bits. + * The workarea must be big enough to contain 32 bytes of data, + * thus the minimum size is (rp, wp, data) = 4 + 4 + 32 = 40 bytes. + * To benefit from concurrent host write-to-buffer and target + * write-to-flash, the workarea must be way bigger than the minimum. + */ + +/* + * Params : + * r0 = workarea start, status (out) + * r1 = workarea end + * r2 = target address + * r3 = count (256 bit words) + * r4 = flash reg base + * + * Clobbered: + * r5 - rp + * r6 - wp, status, tmp + * r7 - loop index, tmp + */ + +#define STM32_FLASH_CR_OFFSET 0x0C /* offset of CR register in FLASH struct */ +#define STM32_FLASH_SR_OFFSET 0x10 /* offset of SR register in FLASH struct */ +#define STM32_CR_PROG 0x00000032 /* PSIZE64 | PG */ +#define STM32_SR_BUSY_MASK 0x00000001 /* BSY */ +#define STM32_SR_ERROR_MASK 0x03ee0000 /* DBECCERR | SNECCERR | RDSERR | RDPERR | OPERR + | INCERR | STRBERR | PGSERR | WRPERR */ + + .thumb_func + .global _start +_start: + ldr r5, [r0, #4] /* read rp */ + +wait_fifo: + ldr r6, [r0, #0] /* read wp */ + cbz r6, exit /* abort if wp == 0, status = 0 */ + subs r6, r6, r5 /* number of bytes available for read in r6 */ + ittt mi /* if wrapped around */ + addmi r6, r1 /* add size of buffer */ + submi r6, r0 + submi r6, #8 + cmp r6, #32 /* wait until 32 bytes are available */ + bcc wait_fifo + + mov r6, #STM32_CR_PROG + str r6, [r4, #STM32_FLASH_CR_OFFSET] + + mov r7, #8 /* program by 8 words = 32 bytes */ +write_flash: + ldr r6, [r5], #0x04 /* read one word from src, increment ptr */ + str r6, [r2], #0x04 /* write one word to dst, increment ptr */ + dsb + cmp r5, r1 /* if rp >= end of buffer ... */ + it cs + addcs r5, r0, #8 /* ... then wrap at buffer start */ + subs r7, r7, #1 /* decrement loop index */ + bne write_flash /* loop if not done */ + +busy: + ldr r6, [r4, #STM32_FLASH_SR_OFFSET] + tst r6, #STM32_SR_BUSY_MASK + bne busy /* operation in progress, wait ... */ + + ldr r7, =STM32_SR_ERROR_MASK + tst r6, r7 + bne error /* fail... */ + + str r5, [r0, #4] /* store rp */ + subs r3, r3, #1 /* decrement count */ + bne wait_fifo /* loop if not done */ + b exit + +error: + movs r7, #0 + str r7, [r0, #4] /* set rp = 0 on error */ + +exit: + mov r0, r6 /* return status in r0 */ + bkpt #0x00 + + .pool + |