drivers/char/hw_random/imx-rngc.c | 32 +++++++++++++++---------------- 1 file changed, 15 insertions(+), 17 deletions(-)
This series simplifies some definitions for register bits and fields. We can then use the FIELD_GET macro to read register fields instead of masking and shifting manually. Tested on an imx258 board (rngb). Martin Kaiser (3): hwrng: imx-rngc - use bitfield macros to read fifo level hwrng: imx-rngc - use bitfield macros to read rng type hwrng: imx-rngc - use BIT(x) for register bit defines drivers/char/hw_random/imx-rngc.c | 32 +++++++++++++++---------------- 1 file changed, 15 insertions(+), 17 deletions(-) -- 2.30.2
This series simplifies some definitions for register bits and fields. We can then use the FIELD_GET macro to read register fields instead of masking and shifting manually. Tested on an imx258 board (rngb). v2: - simpler check if random bytes are available Martin Kaiser (3): hwrng: imx-rngc - simpler check for available random bytes hwrng: imx-rngc - use bitfield macros to read rng type hwrng: imx-rngc - use BIT(x) for register bit defines drivers/char/hw_random/imx-rngc.c | 35 +++++++++++++------------------ 1 file changed, 15 insertions(+), 20 deletions(-) -- 2.30.2
On Fri, May 19, 2023 at 06:04:30PM +0200, Martin Kaiser wrote: > This series simplifies some definitions for register bits and fields. We can > then use the FIELD_GET macro to read register fields instead of masking and > shifting manually. > > Tested on an imx258 board (rngb). > > v2: > - simpler check if random bytes are available > > Martin Kaiser (3): > hwrng: imx-rngc - simpler check for available random bytes > hwrng: imx-rngc - use bitfield macros to read rng type > hwrng: imx-rngc - use BIT(x) for register bit defines > > drivers/char/hw_random/imx-rngc.c | 35 +++++++++++++------------------ > 1 file changed, 15 insertions(+), 20 deletions(-) > > -- > 2.30.2 All applied. Thanks. -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
The "level" field in the status register contains the number of random
bytes that are available in the FIFO. Use GENMASK to extract this field.
We only want to check if level is 0 or if we can read another byte.
There's no need for the shift or the level variable.
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
---
v2:
- remove the shift when checking the fifo level field
drivers/char/hw_random/imx-rngc.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
index a1c24148ed31..cf29c323453a 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/bitfield.h>
#define RNGC_VER_ID 0x0000
#define RNGC_COMMAND 0x0004
@@ -44,8 +45,7 @@
#define RNGC_CTRL_AUTO_SEED 0x00000010
#define RNGC_STATUS_ERROR 0x00010000
-#define RNGC_STATUS_FIFO_LEVEL_MASK 0x00000f00
-#define RNGC_STATUS_FIFO_LEVEL_SHIFT 8
+#define RNGC_STATUS_FIFO_LEVEL_MASK GENMASK(11, 8)
#define RNGC_STATUS_SEED_DONE 0x00000020
#define RNGC_STATUS_ST_DONE 0x00000010
@@ -122,7 +122,6 @@ static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait)
{
struct imx_rngc *rngc = container_of(rng, struct imx_rngc, rng);
unsigned int status;
- unsigned int level;
int retval = 0;
while (max >= sizeof(u32)) {
@@ -132,11 +131,7 @@ static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait)
if (status & RNGC_STATUS_ERROR)
break;
- /* how many random numbers are in FIFO? [0-16] */
- level = (status & RNGC_STATUS_FIFO_LEVEL_MASK) >>
- RNGC_STATUS_FIFO_LEVEL_SHIFT;
-
- if (level) {
+ if (status & RNGC_STATUS_FIFO_LEVEL_MASK) {
/* retrieve a random number from FIFO */
*(u32 *)data = readl(rngc->base + RNGC_FIFO);
--
2.30.2Use the mechanism from bitfield.h to read the rng type field in the
version_id register. This makes the code a tiny bit simpler.
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
---
drivers/char/hw_random/imx-rngc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
index cf29c323453a..b5f7b91bd13e 100644
--- a/drivers/char/hw_random/imx-rngc.c
+++ b/drivers/char/hw_random/imx-rngc.c
@@ -27,7 +27,7 @@
#define RNGC_FIFO 0x0014
/* the fields in the ver id register */
-#define RNGC_TYPE_SHIFT 28
+#define RNG_TYPE GENMASK(31, 28)
#define RNGC_VER_MAJ_SHIFT 8
/* the rng_type field */
@@ -251,7 +251,7 @@ static int imx_rngc_probe(struct platform_device *pdev)
return irq;
ver_id = readl(rngc->base + RNGC_VER_ID);
- rng_type = ver_id >> RNGC_TYPE_SHIFT;
+ rng_type = FIELD_GET(RNG_TYPE, ver_id);
/*
* This driver supports only RNGC and RNGB. (There's a different
* driver for RNGA.)
--
2.30.2Rewrite the defines for register bits to use BIT(x) instead of writing
out the 32-bit number. This makes it easier to compare the code with the
register descriptions in the reference manual.
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
---
drivers/char/hw_random/imx-rngc.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
index b5f7b91bd13e..9c6988c658e2 100644
--- a/drivers/char/hw_random/imx-rngc.c
+++ b/drivers/char/hw_random/imx-rngc.c
@@ -35,19 +35,19 @@
#define RNGC_TYPE_RNGC 0x2
-#define RNGC_CMD_CLR_ERR 0x00000020
-#define RNGC_CMD_CLR_INT 0x00000010
-#define RNGC_CMD_SEED 0x00000002
-#define RNGC_CMD_SELF_TEST 0x00000001
+#define RNGC_CMD_CLR_ERR BIT(5)
+#define RNGC_CMD_CLR_INT BIT(4)
+#define RNGC_CMD_SEED BIT(1)
+#define RNGC_CMD_SELF_TEST BIT(0)
-#define RNGC_CTRL_MASK_ERROR 0x00000040
-#define RNGC_CTRL_MASK_DONE 0x00000020
-#define RNGC_CTRL_AUTO_SEED 0x00000010
+#define RNGC_CTRL_MASK_ERROR BIT(6)
+#define RNGC_CTRL_MASK_DONE BIT(5)
+#define RNGC_CTRL_AUTO_SEED BIT(4)
-#define RNGC_STATUS_ERROR 0x00010000
+#define RNGC_STATUS_ERROR BIT(16)
#define RNGC_STATUS_FIFO_LEVEL_MASK GENMASK(11, 8)
-#define RNGC_STATUS_SEED_DONE 0x00000020
-#define RNGC_STATUS_ST_DONE 0x00000010
+#define RNGC_STATUS_SEED_DONE BIT(5)
+#define RNGC_STATUS_ST_DONE BIT(4)
#define RNGC_ERROR_STATUS_STAT_ERR 0x00000008
--
2.30.2© 2016 - 2026 Red Hat, Inc.