1 files changed, 120 insertions, 0 deletions
diff --git a/watch-library/shared/driver/spiflash.c b/watch-library/shared/driver/spiflash.c
new file mode 100644
index 00000000..da6b2630
--- /dev/null
+++ b/watch-library/shared/driver/spiflash.c
@@ -0,0 +1,120 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022 Joey Castillo
+ *
+ * Ported from MIT-licensed code from CircuitPython
+ * Copyright (c) 2016, 2017 Scott Shawcroft for Adafruit Industries
+ *
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "spiflash.h"
+
+#define SPI_FLASH_FAST_READ false
+
+static void flash_enable(void) {
+    watch_set_pin_level(A3, false);
+}
+
+static void flash_disable(void) {
+    watch_set_pin_level(A3, true);
+}
+
+static bool transfer(uint8_t *command, uint32_t command_length, uint8_t *data_in, uint8_t *data_out, uint32_t data_length) {
+    bool status = watch_spi_write(command, command_length);
+    if (status) {
+        if (data_in != NULL && data_out != NULL) {
+            status = watch_spi_transfer(data_out, data_in, data_length);
+        } else if (data_out != NULL) {
+            status = watch_spi_read(data_out, data_length);
+        } else if (data_in != NULL) {
+            status = watch_spi_write(data_in, data_length);
+        }
+    }
+    flash_disable();
+    return status;
+}
+
+static bool transfer_command(uint8_t command, uint8_t *data_in, uint8_t *data_out, uint32_t data_length) {
+    return transfer(&command, 1, data_in, data_out, data_length);
+}
+
+bool spi_flash_command(uint8_t command) {
+    return transfer_command(command, NULL, NULL, 0);
+}
+
+bool spi_flash_read_command(uint8_t command, uint8_t *data, uint32_t data_length) {
+    return transfer_command(command, NULL, data, data_length);
+}
+
+bool spi_flash_write_command(uint8_t command, uint8_t *data, uint32_t data_length) {
+    return transfer_command(command, data, NULL, data_length);
+}
+
+// Pack the low 24 bits of the address into a uint8_t array.
+static void address_to_bytes(uint32_t address, uint8_t *bytes) {
+    bytes[0] = (address >> 16) & 0xff;
+    bytes[1] = (address >> 8) & 0xff;
+    bytes[2] = address & 0xff;
+}
+
+bool spi_flash_sector_command(uint8_t command, uint32_t address) {
+    uint8_t request[4] = {command, 0x00, 0x00, 0x00};
+    address_to_bytes(address, request + 1);
+    return transfer(request, 4, NULL, NULL, 0);
+}
+
+bool spi_flash_write_data(uint32_t address, uint8_t *data, uint32_t data_length) {
+    uint8_t request[4] = {CMD_PAGE_PROGRAM, 0x00, 0x00, 0x00};
+    // Write the SPI flash write address into the bytes following the command byte.
+    address_to_bytes(address, request + 1);
+    flash_enable();
+    bool status = watch_spi_write(request, 4);
+    if (status) {
+        status = watch_spi_write(data, data_length);
+    }
+    flash_disable();
+    return status;
+}
+
+bool spi_flash_read_data(uint32_t address, uint8_t *data, uint32_t data_length) {
+    uint8_t request[5] = {CMD_READ_DATA, 0x00, 0x00, 0x00};
+    uint8_t command_length = 4;
+    if (SPI_FLASH_FAST_READ) {
+        request[0] = CMD_FAST_READ_DATA;
+        command_length = 5;
+    }
+    // Write the SPI flash read address into the bytes following the command byte.
+    address_to_bytes(address, request + 1);
+    flash_enable();
+    bool status = watch_spi_write(request, command_length);
+    if (status) {
+        status = watch_spi_read(data, data_length);
+    }
+    flash_disable();
+    return status;
+}
+
+void spi_flash_init(void) {
+	gpio_set_pin_level(A3, true);
+	gpio_set_pin_direction(A3, GPIO_DIRECTION_OUT);
+    watch_enable_spi();
+}