[PATCH 1/3] hwrng: imx-rngc - use polling to detect end of self test

Martin Kaiser
2023-08-22T15:28:37Z

Use polling to detect the end of the rngc self test. This is much simpler
than using an interrupt and a completion.

Active waiting is no disadvantage here. The self test is run during
probe, there's nothing we could do in parallel at this time.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
---
drivers/char/hw_random/imx-rngc.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
index e4b385b01b11..85207535fd12 100644
--- a/drivers/char/hw_random/imx-rngc.c
+++ b/drivers/char/hw_random/imx-rngc.c
@@ -17,6 +17,7 @@
#include <linux/hw_random.h>
#include <linux/completion.h>
#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/bitfield.h>

#define RNGC_VER_ID 0x0000
@@ -101,21 +102,19 @@ static inline void imx_rngc_irq_unmask(struct imx_rngc *rngc)

static int imx_rngc_self_test(struct imx_rngc *rngc)
{
- u32 cmd;
+ u32 cmd, status;
int ret;

- imx_rngc_irq_unmask(rngc);
-
/* run self test */
cmd = readl(rngc->base + RNGC_COMMAND);
writel(cmd | RNGC_CMD_SELF_TEST, rngc->base + RNGC_COMMAND);

- ret = wait_for_completion_timeout(&rngc->rng_op_done, msecs_to_jiffies(RNGC_TIMEOUT));
- imx_rngc_irq_mask_clear(rngc);
- if (!ret)
- return -ETIMEDOUT;
+ ret = readl_poll_timeout(rngc->base + RNGC_STATUS, status,
+ status & RNGC_STATUS_ST_DONE, 1000, RNGC_TIMEOUT * 1000);
+ if (ret < 0)
+ return ret;

- return rngc->err_reg ? -EIO : 0;
+ return readl(rngc->base + RNGC_ERROR) ? -EIO : 0;
}

static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait)
--
2.39.2