1 files changed, 166 insertions, 0 deletions
diff --git a/circuitpython/supervisor/shared/external_flash/spi_flash.c b/circuitpython/supervisor/shared/external_flash/spi_flash.c
new file mode 100644
index 0000000..b47508e
--- /dev/null
+++ b/circuitpython/supervisor/shared/external_flash/spi_flash.c
@@ -0,0 +1,166 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * 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 "supervisor/spi_flash_api.h"
+
+#include <stdint.h>
+#include <string.h>
+
+#include "shared-bindings/busio/SPI.h"
+#include "shared-bindings/digitalio/DigitalInOut.h"
+#include "shared-bindings/microcontroller/Pin.h"
+#include "supervisor/shared/external_flash/common_commands.h"
+#include "supervisor/shared/external_flash/external_flash.h"
+#include "py/mpconfig.h"
+
+digitalio_digitalinout_obj_t cs_pin;
+busio_spi_obj_t supervisor_flash_spi_bus;
+
+const external_flash_device *flash_device;
+uint32_t spi_flash_baudrate;
+
+// Enable the flash over SPI.
+static bool flash_enable(void) {
+    if (common_hal_busio_spi_try_lock(&supervisor_flash_spi_bus)) {
+        common_hal_digitalio_digitalinout_set_value(&cs_pin, false);
+        return true;
+    }
+    return false;
+}
+
+// Disable the flash over SPI.
+static void flash_disable(void) {
+    common_hal_digitalio_digitalinout_set_value(&cs_pin, true);
+    common_hal_busio_spi_unlock(&supervisor_flash_spi_bus);
+}
+
+static bool transfer(uint8_t *command, uint32_t command_length, uint8_t *data_in, uint8_t *data_out, uint32_t data_length) {
+    if (!flash_enable()) {
+        return false;
+    }
+    bool status = common_hal_busio_spi_write(&supervisor_flash_spi_bus, command, command_length);
+    if (status) {
+        if (data_in != NULL && data_out != NULL) {
+            status = common_hal_busio_spi_transfer(&supervisor_flash_spi_bus, data_out, data_in, data_length);
+        } else if (data_out != NULL) {
+            status = common_hal_busio_spi_read(&supervisor_flash_spi_bus, data_out, data_length, 0xff);
+        } else if (data_in != NULL) {
+            status = common_hal_busio_spi_write(&supervisor_flash_spi_bus, 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};
+    common_hal_busio_spi_configure(&supervisor_flash_spi_bus, spi_flash_baudrate, 0, 0, 8);
+    // Write the SPI flash write address into the bytes following the command byte.
+    address_to_bytes(address, request + 1);
+    if (!flash_enable()) {
+        return false;
+    }
+    bool status = common_hal_busio_spi_write(&supervisor_flash_spi_bus, request, 4);
+    if (status) {
+        status = common_hal_busio_spi_write(&supervisor_flash_spi_bus, 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 (flash_device->supports_fast_read) {
+        request[0] = CMD_FAST_READ_DATA;
+        command_length = 5;
+    }
+    common_hal_busio_spi_configure(&supervisor_flash_spi_bus, spi_flash_baudrate, 0, 0, 8);
+    // Write the SPI flash read address into the bytes following the command byte.
+    address_to_bytes(address, request + 1);
+    if (!flash_enable()) {
+        return false;
+    }
+    bool status = common_hal_busio_spi_write(&supervisor_flash_spi_bus, request, command_length);
+    if (status) {
+        status = common_hal_busio_spi_read(&supervisor_flash_spi_bus, data, data_length, 0xff);
+    }
+    flash_disable();
+    return status;
+}
+
+void spi_flash_init(void) {
+    cs_pin.base.type = &digitalio_digitalinout_type;
+    common_hal_digitalio_digitalinout_construct(&cs_pin, SPI_FLASH_CS_PIN);
+
+    // Set CS high (disabled).
+    common_hal_digitalio_digitalinout_switch_to_output(&cs_pin, true, DRIVE_MODE_PUSH_PULL);
+    common_hal_digitalio_digitalinout_never_reset(&cs_pin);
+
+    supervisor_flash_spi_bus.base.type = &busio_spi_type;
+    common_hal_busio_spi_construct(&supervisor_flash_spi_bus, SPI_FLASH_SCK_PIN, SPI_FLASH_MOSI_PIN, SPI_FLASH_MISO_PIN, false);
+    common_hal_busio_spi_never_reset(&supervisor_flash_spi_bus);
+
+    return;
+}
+
+void spi_flash_init_device(const external_flash_device *device) {
+    flash_device = device;
+    spi_flash_baudrate = device->max_clock_speed_mhz * 1000000;
+    if (spi_flash_baudrate > SPI_FLASH_MAX_BAUDRATE) {
+        spi_flash_baudrate = SPI_FLASH_MAX_BAUDRATE;
+    }
+    common_hal_busio_spi_configure(&supervisor_flash_spi_bus, spi_flash_baudrate, 0, 0, 8);
+    return;
+}