1 /***************************************************************************
2 * Copyright (C) 2019 by Andreas Bolsch *
3 * andreas.bolsch@mni.thm.de *
5 * This program is free software; you can redistribute it and/or modify *
6 * it under the terms of the GNU General Public License as published by *
7 * the Free Software Foundation; either version 2 of the License, or *
8 * (at your option) any later version. *
10 * This program is distributed in the hope that it will be useful, *
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
13 * GNU General Public License for more details. *
15 * You should have received a copy of the GNU General Public License *
16 * along with this program. If not, see <http://www.gnu.org/licenses/>. *
17 ***************************************************************************/
26 * r0 - total count (bytes), crc32 (out)
27 * r1 - flash page size
28 * r2 - address offset into flash
33 * r5 - address of QSPI_DR
37 #include "../../../../src/flash/nor/stmqspi.h"
40 movs r5, #(1<<SPI_ABORT) /* abort bit mask */
41 ldr r7, [r3, #QSPI_CR] /* get QSPI_CR register */
42 orrs r7, r7, r5 /* set abort bit */
43 str r7, [r3, #QSPI_CR] /* store new CR register */
48 ldr r7, [r3, #QSPI_SR] /* load status */
49 lsrs r7, r7, #(SPI_BUSY+1) /* shift BUSY into C */
50 bcs 0b /* loop until BUSY cleared */
51 movs r7, #(1<<SPI_TCF) /* TCF bitmask */
52 str r7, [r3, #QSPI_FCR] /* clear TCF flag */
56 subs r0, r0, #1 /* decrement count for DLR */
57 subs r1, r1, #1 /* page size mask and for DLR */
58 movs r4, #0x00 /* initialize crc */
59 mvns r4, r4 /* to 0xFFFFFFFF */
61 qspi_abort /* start in clean state */
62 movs r5, #QSPI_DR /* load QSPI_DR address offset */
63 adds r5, r5, r3 /* address of QSPI_DR */
65 mov r7, r2 /* get current start address */
66 orrs r7, r7, r1 /* end of current page */
67 subs r7, r7, r2 /* count-1 to end of page */
68 cmp r7, r0 /* if this count <= remaining */
69 bls write_dlr /* then read to end of page */
70 mov r7, r0 /* else read all remaining */
72 str r7, [r3, #QSPI_DLR] /* size-1 in DLR register */
73 ldr r7, ccr_page_read /* CCR for page read */
74 str r7, [r3, #QSPI_CCR] /* initiate transfer */
75 str r2, [r3, #QSPI_AR] /* store SPI start address */
76 ldr r7, [r3, #QSPI_SR] /* wait for command startup */
77 ldr r6, =0x04C11DB7 /* CRC32 polynomial */
79 ldrb r7, [r5] /* read next byte from DR */
80 lsls r7, r7, #24 /* shift into msb */
82 .rept 8 /* unrolled bit loop */
83 asrs r7, r4, #31 /* copy bit 31 into bits 0 to 31 */
84 ands r7, r7, r6 /* r7 neg. -> CRC32XOR, pos. -> 0x0 */
85 lsls r4, r4, #1 /* shift result */
86 eors r4, r4, r7 /* eor by CRC32XOR or 0x0 */
88 adds r2, r2, #1 /* increment address */
89 subs r0, r0, #1 /* decrement (count-1) */
90 bmi exit /* stop if no data left */
91 tst r2, r1 /* page end ? */
92 bne read_loop /* if not, then next byte */
94 bal start_read /* then next page */
98 mvns r0, r4 /* invert to get final result */
99 qspi_abort /* to idle state */
100 .align 2 /* align to word, bkpt is 4 words */
101 bkpt #0 /* before code end for exit_point */
102 .align 2 /* align to word */
104 .space 4 /* not used */
106 .space 4 /* QSPI_CCR value for read command */
107 .space 4 /* not used */
108 .space 4 /* not used */