mirror of https://github.com/hsoft/collapseos.git
115 lines
2.6 KiB
C
115 lines
2.6 KiB
C
#include <stdio.h>
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#include "sdc.h"
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void sdc_init(SDC *sdc)
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{
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sdc->selected = false;
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sdc->initstat = 0;
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sdc->recvidx = 0;
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sdc->sendidx = -1;
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sdc->resp = 0xff;
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}
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void sdc_cslow(SDC *sdc)
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{
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sdc->selected = true;
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}
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void sdc_cshigh(SDC *sdc)
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{
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sdc->selected = false;
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}
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void sdc_spi_wr(SDC *sdc, uint8_t val)
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{
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if (!sdc->selected) {
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return;
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}
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sdc->resp = 0xff;
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if (sdc->initstat < 8) {
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// not woken yet.
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sdc->initstat++;
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return;
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}
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if (sdc->sendidx >= 0) {
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sdc->resp = sdc->sendbuf[sdc->sendidx++];
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if (sdc->sendidx == 5) {
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sdc->sendidx = -1;
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}
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return;
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}
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if ((sdc->recvidx == 0) && ((val > 0x7f) || (val < 0x40))) {
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// not a command
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return;
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}
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sdc->recvbuf[sdc->recvidx++] = val;
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if (sdc->recvidx < 6) {
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// incomplete command
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return;
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}
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// Command complete
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val &= 0x3f;
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sdc->recvidx = 0;
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uint8_t *b = sdc->recvbuf;
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fprintf(stderr, "cmd %02x %02x %02x %02x %02x\n", b[0], b[1], b[2], b[3], b[4]);
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uint8_t cmd = b[0] & 0x3f;
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if (sdc->initstat == 8) {
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// At this stage, we're expecting CMD0
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if (cmd == 0) {
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sdc->initstat++;
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sdc->sendbuf[4] = 0x01;
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sdc->sendidx = 4;
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}
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return;
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}
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if (sdc->initstat == 9) {
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// At this stage, we're expecting CMD8 with 0x1aa arg2
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if ((cmd == 8) && (b[3] == 0x01) && (b[4] == 0xaa)) {
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sdc->initstat++;
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sdc->sendbuf[0] = 0x01;
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sdc->sendbuf[1] = 0;
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sdc->sendbuf[2] = 0;
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sdc->sendbuf[3] = 0x01;
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sdc->sendbuf[4] = 0xaa;
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sdc->sendidx = 0;
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} else {
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sdc-> initstat = 8;
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}
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return;
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}
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if (sdc->initstat == 10) {
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// At this stage, we're expecting CMD55
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if (cmd == 55) {
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sdc->initstat++;
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sdc->sendbuf[4] = 0x01;
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sdc->sendidx = 4;
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} else {
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sdc->initstat = 8;
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}
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return;
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}
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if (sdc->initstat == 11) {
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// At this stage, we're expecting CMD41
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if ((cmd == 41) && (b[1] == 0x40) && (b[2] == 0x00)) {
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sdc->initstat++;
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sdc->sendbuf[4] = 0x00;
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sdc->sendidx = 4;
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} else {
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sdc->initstat = 8;
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}
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return;
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}
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// We have a fully initialized card.
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// Simulate success for any unknown command.
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sdc->sendbuf[4] = 0x00;
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sdc->sendidx = 4;
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}
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uint8_t sdc_spi_rd(SDC *sdc)
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{
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if (!sdc->selected) {
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return 0xff;
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}
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return sdc->resp;
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}
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