Change in flashrom[master]: developerbox_spi.c: Refactor singleton states into reentrant pattern

[Edward O'Callaghan (Code Review)]

Edward O'Callaghan has submitted this change. ( https://review.coreboot.org/c/flashrom/+/54993 )

Change subject: developerbox_spi.c: Refactor singleton states into reentrant pattern
......................................................................

developerbox_spi.c: Refactor singleton states into reentrant pattern

Move global singleton states into a struct and store within
the bitbang_spi_master data field for the life-time of the driver.

This is one of the steps on the way to move spi_master data
memory management behind the initialisation API, for more
context see other patches under the same topic "register_master_api".

BUG=b:185191942
TEST=builds

Change-Id: I84bf0cffa4a14e58103bdb1e7e65ec2475344f12
Signed-off-by: Anastasia Klimchuk 
Reviewed-on: https://review.coreboot.org/c/flashrom/+/54993
Tested-by: build bot (Jenkins) 
Reviewed-by: Angel Pons 
Reviewed-by: Edward O'Callaghan 
---
M developerbox_spi.c
1 file changed, 39 insertions(+), 16 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Angel Pons: Looks good to me, approved
  Edward O'Callaghan: Looks good to me, approved

diff --git a/developerbox_spi.c b/developerbox_spi.c
index e741890..e4ab6f6 100644
--- a/developerbox_spi.c
+++ b/developerbox_spi.c
@@ -60,15 +60,18 @@
    {0},
 };

-static struct libusb_context *usb_ctx;
-static libusb_device_handle *cp210x_handle;
+struct devbox_spi_data {
+	struct libusb_context *usb_ctx;
+	libusb_device_handle *cp210x_handle;
+};

-static int cp210x_gpio_get(void)
+static int cp210x_gpio_get(void *spi_data)
 {
    int res;
    uint8_t gpio;
+	struct devbox_spi_data *data = spi_data;

-	res = libusb_control_transfer(cp210x_handle, REQTYPE_DEVICE_TO_HOST,
+	res = libusb_control_transfer(data->cp210x_handle, REQTYPE_DEVICE_TO_HOST,
    		CP210X_VENDOR_SPECIFIC, CP210X_READ_LATCH,
    		0, &gpio, 1, 0);
    if (res < 0) {
@@ -79,15 +82,16 @@
    return gpio;
 }

-static void cp210x_gpio_set(uint8_t val, uint8_t mask)
+static void cp210x_gpio_set(uint8_t val, uint8_t mask, void *spi_data)
 {
    int res;
    uint16_t gpio;
+	struct devbox_spi_data *data = spi_data;

gpio = ((val & 0xf) << 8) | (mask & 0xf);

/* Set relay state on the card */
-	res = libusb_control_transfer(cp210x_handle, REQTYPE_HOST_TO_DEVICE,
+	res = libusb_control_transfer(data->cp210x_handle, REQTYPE_HOST_TO_DEVICE,
    		CP210X_VENDOR_SPECIFIC, CP210X_WRITE_LATCH,
    		gpio, NULL, 0, 0);
    if (res < 0)
@@ -96,28 +100,29 @@

static void cp210x_bitbang_set_cs(int val, void *spi_data)
 {
-	cp210x_gpio_set(val << DEVELOPERBOX_SPI_CS, 1 << DEVELOPERBOX_SPI_CS);
+	cp210x_gpio_set(val << DEVELOPERBOX_SPI_CS, 1 << DEVELOPERBOX_SPI_CS, spi_data);
 }

static void cp210x_bitbang_set_sck(int val, void *spi_data)
 {
-	cp210x_gpio_set(val << DEVELOPERBOX_SPI_SCK, 1 << DEVELOPERBOX_SPI_SCK);
+	cp210x_gpio_set(val << DEVELOPERBOX_SPI_SCK, 1 << DEVELOPERBOX_SPI_SCK, spi_data);
 }

static void cp210x_bitbang_set_mosi(int val, void *spi_data)
 {
-	cp210x_gpio_set(val << DEVELOPERBOX_SPI_MOSI, 1 << DEVELOPERBOX_SPI_MOSI);
+	cp210x_gpio_set(val << DEVELOPERBOX_SPI_MOSI, 1 << DEVELOPERBOX_SPI_MOSI, spi_data);
 }

static int cp210x_bitbang_get_miso(void *spi_data)
 {
-	return !!(cp210x_gpio_get() & (1 << DEVELOPERBOX_SPI_MISO));
+	return !!(cp210x_gpio_get(spi_data) & (1 << DEVELOPERBOX_SPI_MISO));
 }

static void cp210x_bitbang_set_sck_set_mosi(int sck, int mosi, void *spi_data)
 {
    cp210x_gpio_set(sck << DEVELOPERBOX_SPI_SCK | mosi << DEVELOPERBOX_SPI_MOSI,
-			  1 << DEVELOPERBOX_SPI_SCK |    1 << DEVELOPERBOX_SPI_MOSI);
+			  1 << DEVELOPERBOX_SPI_SCK |    1 << DEVELOPERBOX_SPI_MOSI,
+			  spi_data);
 }

static const struct bitbang_spi_master bitbang_spi_master_cp210x = {
@@ -128,16 +133,22 @@
    .set_sck_set_mosi = cp210x_bitbang_set_sck_set_mosi,
 };

-static int developerbox_spi_shutdown(void *data)
+static int developerbox_spi_shutdown(void *spi_data)
 {
-	libusb_close(cp210x_handle);
-	libusb_exit(usb_ctx);
+	struct devbox_spi_data *data = spi_data;

+	libusb_close(data->cp210x_handle);
+	libusb_exit(data->usb_ctx);
+
+	free(data);
    return 0;
 }

int developerbox_spi_init(void)
 {
+	struct libusb_context *usb_ctx;
+	libusb_device_handle *cp210x_handle;
+
    libusb_init(&usb_ctx);
    if (!usb_ctx) {
    	msg_perr("Could not initialize libusb!\n");
@@ -155,15 +166,27 @@
    	goto err_exit;
    }

-	if (register_shutdown(developerbox_spi_shutdown, NULL))
+	struct devbox_spi_data *data = calloc(1, sizeof(*data));
+	if (!data) {
+		msg_perr("Unable to allocate space for SPI master data\n");
    	goto err_exit;
+	}
+	data->usb_ctx = usb_ctx;
+	data->cp210x_handle = cp210x_handle;

-	if (register_spi_bitbang_master(&bitbang_spi_master_cp210x, NULL))
+	if (register_shutdown(developerbox_spi_shutdown, data)) {
+		free(data);
    	goto err_exit;
+	}
+
+	if (register_spi_bitbang_master(&bitbang_spi_master_cp210x, data))
+		return 1; /* shutdown function does the cleanup */

return 0;

err_exit:
+	if (cp210x_handle)
+		libusb_close(cp210x_handle);
    libusb_exit(usb_ctx);
    return 1;
 }