WIP: add mmap backend for virtual spi flash

source/platform/virtual/spi.c

@@ -4,16 +4,54 @@
 
 #include <spi.h>
 
+#include <stdio.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <string.h>
+#include <spi_flash.h>
+
+// XXX: 16 is used in other places in this file too
+#define FLASH_SIZE (1 << 16)
+
 static int virtual_spi_tx_rx(struct spi_dev *dev, void *rx_buf, size_t rx_len,
-	const void *tx_buf, size_t tx_len);
+			     const void *tx_buf, size_t tx_len);
 
 static struct spi_ops virtual_spi_ops = {
 	.tx_rx = virtual_spi_tx_rx,
 };
 
-static void virtual_spi_init(void)
+// XXX: make part of dev struct
+static unsigned char *flash_map;
+
+static int virtual_spi_init(void)
 {
-    /* TODO */
+	/* TODO: close this fd */
+	FILE *flash_fd;
+	int exists = 0;
+
+	exists = access("flash", F_OK) != -1;
+	/* XXX: treat not existing separately from existing file, since we want to
+	 * null one that doesn't exist yet */
+	flash_fd = fopen("flash", "ab+");
+	if (!exists) {
+		fprintf(stderr,
+			"flash doesn't exist yet, creating and filling now\n");
+		char buf[FLASH_SIZE];
+		int ret = fwrite(buf, sizeof(char), FLASH_SIZE, flash_fd);
+		fprintf(stderr, "fwrite ret: %d\n", ret);
+	}
+
+	if (flash_fd == NULL) {
+		perror("flash_open");
+		fprintf(stderr, "spi init failed\n");
+		return 1;
+	}
+	flash_map =
+	    mmap(NULL, FLASH_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
+		 fileno(flash_fd), 0);
+	fprintf(stderr, "flash: %p\n", flash_map);
+
+	return 0;
 }
 
 struct spi_dev *spi_probe(void)
@@ -24,11 +62,14 @@ struct spi_dev *spi_probe(void)
 		return NULL;
 
 	dev->ops = &virtual_spi_ops;
-    /*
-	dev->dev_id = SPI1;
+	/*
+	   dev->dev_id = SPI1;
 
-    */
-	virtual_spi_init();
+	 */
+	if (virtual_spi_init()) {
+		free(dev);
+		return NULL;
+	}
 
 	return dev;
 }
@@ -36,10 +77,74 @@ struct spi_dev *spi_probe(void)
 void spi_release(struct spi_dev *dev)
 {
 	free(dev);
+	/* TODO: close fd, close mmap */
 }
 
 static int virtual_spi_tx_rx(struct spi_dev *dev, void *rx_buf, size_t rx_len,
-	const void *tx_buf, size_t tx_len)
+			     const void *tx_buf, size_t tx_len)
 {
+	unsigned char *rx_buf_c = (unsigned char *)rx_buf;
+	unsigned char *tx_buf_c = (unsigned char *)tx_buf;
+
+	unsigned char cmd = tx_buf_c[0];
+
+	fprintf(stderr, "? RX len: %ld\n", rx_len);
+
+	if (tx_buf != NULL) {
+		fprintf(stderr, "? TX Command: %d\n", cmd);
+		fprintf(stderr, "? TX len: %ld\n", tx_len);
+		if (cmd == SPI_FLASH_JEDEC_ID) {
+			if (rx_len != 3) {
+				fprintf(stderr, "UNEXPECTED RX_LEN\n");
+			}
+			fprintf(stderr, "SPI_FLASH_JEDEC_ID\n");
+			rx_buf_c[0] = 0x1;
+			rx_buf_c[1] = 0x1;
+			rx_buf_c[2] = 16;
+		}
+
+		if (cmd == SPI_FLASH_READ) {
+			fprintf(stderr, "SPI_FLASH_READ\n");
+			unsigned int addr = (tx_buf_c[1] << 16) +
+			    (tx_buf_c[2] << 8) + tx_buf_c[3];
+			fprintf(stderr, "addr: %d\n", addr);
+			fprintf(stderr, "memmove: %d\n", addr);
+			memmove(rx_buf_c, flash_map + addr, rx_len);
+		}
+
+		if (cmd == SPI_FLASH_PAGE_PROGRAM) {
+			fprintf(stderr, "SPI_FLASH_PAGE_PROGRAM\n");
+			unsigned int addr = (tx_buf_c[1] << 16) +
+			    (tx_buf_c[2] << 8) + tx_buf_c[3];
+			fprintf(stderr, "addr: %d\n", addr);
+			fprintf(stderr, "memmove: %d\n", addr);
+			memmove(flash_map + addr, tx_buf_c + 4, tx_len - 4);
+		}
+
+		if (cmd == SPI_FLASH_ERASE_4K) {
+			fprintf(stderr, "SPI_FLASH_ERASE_4K\n");
+			unsigned int addr = (tx_buf_c[1] << 16) +
+			    (tx_buf_c[2] << 8) + tx_buf_c[3];
+			fprintf(stderr, "addr: %d\n", addr);
+			memset(flash_map + addr, 0, 4096);
+		}
+
+		if (cmd == SPI_FLASH_READ_SR1) {
+			fprintf(stderr, "SPI_FLASH_READ_SR1\n");
+			/* Just report read/write/erase as done, we are never busy with mmap */
+			rx_buf_c[0] = 0;
+		}
+
+		if (cmd == SPI_FLASH_WRITE_ENABLE) {
+			fprintf(stderr, "SPI_FLASH_WRITE_ENABLE\n");
+			/* These can be stubs */
+		}
+
+		if (cmd == SPI_FLASH_WRITE_DISABLE) {
+			fprintf(stderr, "SPI_FLASH_WRITE_DISABLE\n");
+			/* These can be stubs */
+		}
+	}
+
 	return 0;
 }