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Subject[PATCH v4 4/5] fpga manager: xilinx-spi: add error checking after gpiod_get_value()
Date
Current code calls gpiod_get_value() without error checking. Should the
GPIO controller fail, execution would continue without any error message.

Fix by checking for negative error values.

Reported-by: Tom Rix <trix@redhat.com>
Reviewed-by: Tom Rix <trix@redhat.com>
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>

---

Changes in v4:
- add Reviewed-by Tom Rix

Changes in v3:
- rebase on previous patches

This patch is new in v2
---
drivers/fpga/xilinx-spi.c | 35 +++++++++++++++++++++++++++--------
1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/drivers/fpga/xilinx-spi.c b/drivers/fpga/xilinx-spi.c
index fba8eb4866a7..52aab5a1f0ba 100644
--- a/drivers/fpga/xilinx-spi.c
+++ b/drivers/fpga/xilinx-spi.c
@@ -27,11 +27,22 @@ struct xilinx_spi_conf {
struct gpio_desc *done;
};

-static enum fpga_mgr_states xilinx_spi_state(struct fpga_manager *mgr)
+static int get_done_gpio(struct fpga_manager *mgr)
{
struct xilinx_spi_conf *conf = mgr->priv;
+ int ret;
+
+ ret = gpiod_get_value(conf->done);
+
+ if (ret < 0)
+ dev_err(&mgr->dev, "Error reading DONE (%d)\n", ret);

- if (!gpiod_get_value(conf->done))
+ return ret;
+}
+
+static enum fpga_mgr_states xilinx_spi_state(struct fpga_manager *mgr)
+{
+ if (!get_done_gpio(mgr))
return FPGA_MGR_STATE_RESET;

return FPGA_MGR_STATE_UNKNOWN;
@@ -57,10 +68,21 @@ static int wait_for_init_b(struct fpga_manager *mgr, int value,

if (conf->init_b) {
while (time_before(jiffies, timeout)) {
- if (gpiod_get_value(conf->init_b) == value)
+ int ret = gpiod_get_value(conf->init_b);
+
+ if (ret == value)
return 0;
+
+ if (ret < 0) {
+ dev_err(&mgr->dev, "Error reading INIT_B (%d)\n", ret);
+ return ret;
+ }
+
usleep_range(100, 400);
}
+
+ dev_err(&mgr->dev, "Timeout waiting for INIT_B to %s\n",
+ value ? "assert" : "deassert");
return -ETIMEDOUT;
}

@@ -85,7 +107,6 @@ static int xilinx_spi_write_init(struct fpga_manager *mgr,

err = wait_for_init_b(mgr, 1, 1); /* min is 500 ns */
if (err) {
- dev_err(&mgr->dev, "INIT_B pin did not go low\n");
gpiod_set_value(conf->prog_b, 0);
return err;
}
@@ -93,12 +114,10 @@ static int xilinx_spi_write_init(struct fpga_manager *mgr,
gpiod_set_value(conf->prog_b, 0);

err = wait_for_init_b(mgr, 0, 0);
- if (err) {
- dev_err(&mgr->dev, "INIT_B pin did not go high\n");
+ if (err)
return err;
- }

- if (gpiod_get_value(conf->done)) {
+ if (get_done_gpio(mgr)) {
dev_err(&mgr->dev, "Unexpected DONE pin state...\n");
return -EIO;
}
--
2.28.0
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