mirror of
https://github.com/isometimes/rpi4-osdev
synced 2024-09-19 21:32:58 +00:00
100 lines
2.5 KiB
C
100 lines
2.5 KiB
C
#include "../include/io.h"
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#include "../include/fb.h"
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// SPI
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struct Spi0Regs {
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volatile unsigned int cs;
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volatile unsigned int fifo;
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volatile unsigned int clock;
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volatile unsigned int data_length;
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volatile unsigned int ltoh;
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volatile unsigned int dc;
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};
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#define REGS_SPI0 ((struct Spi0Regs *)(PERIPHERAL_BASE + 0x00204000))
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// CS Register
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#define CS_LEN_LONG (1 << 25)
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#define CS_DMA_LEN (1 << 24)
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#define CS_CSPOL2 (1 << 23)
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#define CS_CSPOL1 (1 << 22)
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#define CS_CSPOL0 (1 << 21)
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#define CS_RXF (1 << 20)
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#define CS_RXR (1 << 19)
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#define CS_TXD (1 << 18)
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#define CS_RXD (1 << 17)
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#define CS_DONE (1 << 16)
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#define CS_LEN (1 << 13)
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#define CS_REN (1 << 12)
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#define CS_ADCS (1 << 11)
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#define CS_INTR (1 << 10)
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#define CS_INTD (1 << 9)
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#define CS_DMAEN (1 << 8)
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#define CS_TA (1 << 7)
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#define CS_CSPOL (1 << 6)
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#define CS_CLEAR_RX (1 << 5)
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#define CS_CLEAR_TX (1 << 4)
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#define CS_CPOL__SHIFT 3
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#define CS_CPHA__SHIFT 2
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#define CS_CS (1 << 0)
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#define CS_CS__SHIFT 0
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void spi_init() {
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gpio_useAsAlt0(7); //CS1
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gpio_initOutputPinWithPullNone(8); //CS0
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gpio_useAsAlt0(9); //MISO
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gpio_useAsAlt0(10); //MOSI
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gpio_useAsAlt0(11); //SCLK
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}
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void spi_chip_select(unsigned char chip_select) {
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gpio_setPinOutputBool(8, chip_select);
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}
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void spi_send_recv(unsigned char *sbuffer, unsigned char *rbuffer, unsigned int size) {
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REGS_SPI0->data_length = size;
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REGS_SPI0->cs = REGS_SPI0->cs | CS_CLEAR_RX | CS_CLEAR_TX | CS_TA;
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unsigned int read_count = 0;
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unsigned int write_count = 0;
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while(read_count < size || write_count < size) {
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while(write_count < size && REGS_SPI0->cs & CS_TXD) {
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if (sbuffer) {
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REGS_SPI0->fifo = *sbuffer++;
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} else {
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REGS_SPI0->fifo = 0;
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}
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write_count++;
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}
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while(read_count < size && REGS_SPI0->cs & CS_RXD) {
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unsigned int data = REGS_SPI0->fifo;
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if (rbuffer) {
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*rbuffer++ = data;
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}
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read_count++;
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}
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}
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while(!(REGS_SPI0->cs & CS_DONE)) {
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while(REGS_SPI0->cs & CS_RXD) {
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unsigned int r = REGS_SPI0->fifo;
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debughex(r);
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}
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}
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REGS_SPI0->cs = (REGS_SPI0->cs & ~CS_TA);
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}
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void spi_send(unsigned char *data, unsigned int size) {
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spi_send_recv(data, 0, size);
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}
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void spi_recv(unsigned char *data, unsigned int size) {
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spi_send_recv(0, data, size);
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}
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