1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 /***************************************************************************
4 * Copyright (C) 2019 by Andreas Bolsch *
5 * andreas.bolsch@mni.thm.de *
6 ***************************************************************************/
15 * r0 - total count (bytes), crc32 (out)
16 * r1 - flash page size
17 * r2 - address offset into flash
18 * r3 - OCTOSPI io_base
22 * r5 - address of OCTOSPI_DR
23 * r6 - address of OCTOSPI_CCR
27 #include "../../../../src/flash/nor/stmqspi.h"
29 #define OCTOSPI_CCR_CCR (OCTOSPI_CCR - OCTOSPI_CCR)
30 #define OCTOSPI_TCR_CCR (OCTOSPI_TCR - OCTOSPI_CCR)
31 #define OCTOSPI_IR_CCR (OCTOSPI_IR - OCTOSPI_CCR)
34 movs r5, #(1<<SPI_ABORT) /* abort bit mask */
35 ldr r7, [r3, #OCTOSPI_CR] /* get OCTOSPI CR register */
36 orrs r7, r7, r5 /* set abort bit */
37 str r7, [r3, #OCTOSPI_CR] /* store new CR register */
42 ldr r7, [r3, #OCTOSPI_SR] /* load status */
43 lsrs r7, r7, #(SPI_BUSY+1) /* shift BUSY into C */
44 bcs 0b /* loop until BUSY cleared */
45 movs r7, #(1<<SPI_TCF) /* TCF bitmask */
46 str r7, [r3, #OCTOSPI_FCR] /* clear TCF flag */
50 subs r0, r0, #1 /* decrement count for DLR */
51 subs r1, r1, #1 /* page size mask and for DLR */
52 movs r4, #0x00 /* initialize crc */
53 mvns r4, r4 /* to 0xFFFFFFFF */
55 octospi_abort /* start in clean state */
56 movs r5, #OCTOSPI_DR /* load OCTOSPI_DR address offset */
57 adds r5, r5, r3 /* address of OCTOSPI_DR */
58 movs r6, #OCTOSPI_CCR-OCTOSPI_DR /* load OCTOSPI_CCR address offset */
59 adds r6, r6, r5 /* address of OCTOSPI_CCR */
61 ldr r7, cr_page_read /* indirect read mode */
62 str r7, [r3, #OCTOSPI_CR] /* set mode */
63 mov r7, r2 /* get current start address */
64 orrs r7, r7, r1 /* end of current page */
65 subs r7, r7, r2 /* count-1 to end of page */
66 cmp r7, r0 /* if this count <= remaining */
67 bls write_dlr /* then read to end of page */
68 mov r7, r0 /* else read all remaining */
70 str r7, [r3, #OCTOSPI_DLR] /* size-1 in DLR register */
71 ldr r7, ccr_page_read /* CCR for read */
72 str r7, [r6, #OCTOSPI_CCR_CCR] /* initiate transfer */
73 ldr r7, tcr_page_read /* TCR for read */
74 str r7, [r6, #OCTOSPI_TCR_CCR] /* instruction */
75 ldr r7, ir_page_read /* IR for read */
76 str r7, [r6, #OCTOSPI_IR_CCR] /* instruction */
77 str r2, [r3, #OCTOSPI_AR] /* store SPI start address */
78 ldr r6, =0x04C11DB7 /* CRC32 polynomial */
80 ldrb r7, [r5] /* read next byte from DR */
81 lsls r7, r7, #24 /* shift into msb */
83 .rept 8 /* unrolled bit loop */
84 asrs r7, r4, #31 /* copy bit 31 into bits 0 to 31 */
85 ands r7, r7, r6 /* r7 neg. -> CRC32XOR, pos. -> 0x0 */
86 lsls r4, r4, #1 /* shift result */
87 eors r4, r4, r7 /* eor by CRC32XOR or 0x0 */
89 adds r2, r2, #1 /* increment address */
90 subs r0, r0, #1 /* decrement (count-1) */
91 bmi exit /* stop if no data left */
92 tst r2, r1 /* page end ? */
93 bne read_loop /* if not, then next byte */
95 bal start_read /* then next page */
99 mvns r0, r4 /* invert to get final result */
100 octospi_abort /* to idle state */
101 .align 2 /* align to word, bkpt is 4 words */
102 bkpt #0 /* before code end for exit_point */
103 .align 2 /* align to word */
106 .space 4 /* OCTOSPI_CR value for read command */
108 .space 4 /* OCTOSPI_CCR value for read command */
110 .space 4 /* OCTOSPI_TCR value for read command */
112 .space 4 /* OCTOSPI_IR value for read command */