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

[Anastasia Klimchuk (Code Review)]

Anastasia Klimchuk has uploaded this change for review. ( https://review.coreboot.org/c/flashrom/+/52285 )

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

linux_spi.c: Refactor singleton states into reentrant pattern

Move global singleton states into a struct and store within
the 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".

TEST=builds
BUG=b:140394053

Change-Id: I93408c2ca846fca6a1c7eda7180862c51bd48078
Signed-off-by: Anastasia Klimchuk 
---
M linux_spi.c
1 file changed, 34 insertions(+), 11 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/85/52285/1

diff --git a/linux_spi.c b/linux_spi.c
index ae5c318..d22b714 100644
--- a/linux_spi.c
+++ b/linux_spi.c
@@ -44,29 +44,37 @@
  * HummingBoard
  */

-static int fd = -1;
 #define BUF_SIZE_FROM_SYSFS	"/sys/module/spidev/parameters/bufsiz"
-static size_t max_kernel_buf_size;
+
+struct linux_spi_data {
+	int fd;
+	size_t max_kernel_buf_size;
+};

static int linux_spi_read(struct flashctx *flash, uint8_t *buf, unsigned int start, unsigned int len)
 {
+	struct linux_spi_data *spi_data = flash->mst->spi.data;
    /* Older kernels use a single buffer for combined input and output
       data. So account for longest possible command + address, too. */
-	return spi_read_chunked(flash, buf, start, len, max_kernel_buf_size - 5);
+	return spi_read_chunked(flash, buf, start, len, spi_data->max_kernel_buf_size - 5);
 }

static int linux_spi_write_256(struct flashctx *flash, const uint8_t *buf, unsigned int start, unsigned int len)
 {
+	struct linux_spi_data *spi_data = flash->mst->spi.data;
    /* 5 bytes must be reserved for longest possible command + address. */
-	return spi_write_chunked(flash, buf, start, len, max_kernel_buf_size - 5);
+	return spi_write_chunked(flash, buf, start, len, spi_data->max_kernel_buf_size - 5);
 }

static int linux_spi_shutdown(void *data)
 {
-	if (fd != -1) {
-		close(fd);
-		fd = -1;
+	struct linux_spi_data *spi_data = (struct linux_spi_data *) data;
+	if (spi_data->fd != -1) {
+		close(spi_data->fd);
+		spi_data->fd = -1;
    }
+
+	free(spi_data);
    return 0;
 }

@@ -75,6 +83,7 @@
    			  const unsigned char *txbuf,
    			  unsigned char *rxbuf)
 {
+	struct linux_spi_data *spi_data = flash->mst->spi.data;
    int iocontrol_code;
    struct spi_ioc_transfer msg[2] = {
    	{
@@ -87,7 +96,7 @@
    	},
    };

-	if (fd == -1)
+	if (spi_data->fd == -1)
    	return -1;
    /* The implementation currently does not support requests that
       don't start with sending a command. */
@@ -101,14 +110,14 @@
    else
    	iocontrol_code = SPI_IOC_MESSAGE(2);

-	if (ioctl(fd, iocontrol_code, msg) == -1) {
+	if (ioctl(spi_data->fd, iocontrol_code, msg) == -1) {
    	msg_cerr("%s: ioctl: %s\n", __func__, strerror(errno));
    	return -1;
    }
    return 0;
 }

-static const struct spi_master spi_master_linux = {
+static struct spi_master spi_master_linux = {
    .features	= SPI_MASTER_4BA,
    .max_data_read	= MAX_DATA_UNSPECIFIED, /* TODO? */
    .max_data_write	= MAX_DATA_UNSPECIFIED, /* TODO? */
@@ -167,6 +176,9 @@
    /* SPI mode 0 (beware this also includes: MSB first, CS active low and others */
    const uint8_t mode = SPI_MODE_0;
    const uint8_t bits = 8;
+	int fd = -1;
+	size_t max_kernel_buf_size;
+	struct linux_spi_data *spi_data;
    int ret = 0;

p = extract_programmer_param("spispeed");
@@ -226,7 +238,18 @@
    max_kernel_buf_size = get_max_kernel_buf_size();
    msg_pdbg("%s: max_kernel_buf_size: %zu\n", __func__, max_kernel_buf_size);

-	if (register_shutdown(linux_spi_shutdown, NULL)) {
+	spi_data = calloc(1, sizeof(*spi_data));
+	if (!spi_data) {
+		msg_perr("Unable to allocated space for SPI master data\n");
+		ret = SPI_GENERIC_ERROR;
+		goto init_err;
+	}
+	spi_data->fd = fd;
+	spi_data->max_kernel_buf_size = max_kernel_buf_size;
+	spi_master_linux.data = spi_data;
+
+	if (register_shutdown(linux_spi_shutdown, spi_data)) {
+		free(spi_data);
    	ret = 1;
    	goto init_err;
    }