Read the rng type and hardware revision during probe. Fail the probe
operation if the type is not one of rngc or rngb.
(There's also an rnga type, which needs a different driver.)
Display the type and revision in a debug print if probe was successful.
Signed-off-by: Martin Kaiser <martin@xxxxxxxxx>
---
drivers/char/hw_random/imx-rngc.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
index 8222055b9e9b..27d85fced30b 100644
--- a/drivers/char/hw_random/imx-rngc.c
+++ b/drivers/char/hw_random/imx-rngc.c
@@ -18,12 +18,22 @@
#include <linux/completion.h>
#include <linux/io.h>
+#define RNGC_VER_ID 0x0000
#define RNGC_COMMAND 0x0004
#define RNGC_CONTROL 0x0008
#define RNGC_STATUS 0x000C
#define RNGC_ERROR 0x0010
#define RNGC_FIFO 0x0014
+/* the fields in the ver id register */
+#define RNGC_TYPE_SHIFT 28
+#define RNGC_VER_MAJ_SHIFT 8
+
+/* the rng_type field */
+#define RNGC_TYPE_RNGB 0x1
+#define RNGC_TYPE_RNGC 0x2
+
+
#define RNGC_CMD_CLR_ERR 0x00000020
#define RNGC_CMD_CLR_INT 0x00000010
#define RNGC_CMD_SEED 0x00000002
@@ -212,6 +222,8 @@ static int imx_rngc_probe(struct platform_device *pdev)
struct imx_rngc *rngc;
int ret;
int irq;
+ u32 ver_id;
+ u8 rng_type;
rngc = devm_kzalloc(&pdev->dev, sizeof(*rngc), GFP_KERNEL);
if (!rngc)
@@ -237,6 +249,17 @@ static int imx_rngc_probe(struct platform_device *pdev)
if (ret)
return ret;
+ ver_id = readl(rngc->base + RNGC_VER_ID);
+ rng_type = ver_id >> RNGC_TYPE_SHIFT;
+ /*
+ * This driver supports only RNGC and RNGB. (There's a different
+ * driver for RNGA.)
+ */
+ if (rng_type != RNGC_TYPE_RNGC && rng_type != RNGC_TYPE_RNGB) {
+ ret = -ENODEV;
+ goto err;
+ }
+
ret = devm_request_irq(&pdev->dev,
irq, imx_rngc_irq, 0, pdev->name, (void *)rngc);
if (ret) {
@@ -269,7 +292,10 @@ static int imx_rngc_probe(struct platform_device *pdev)
goto err;
}
- dev_info(&pdev->dev, "Freescale RNGC registered.\n");
+ dev_info(&pdev->dev,
+ "Freescale RNG%c registered (HW revision %d.%02d)\n",
+ rng_type == RNGC_TYPE_RNGB ? 'B' : 'C',
+ (ver_id >> RNGC_VER_MAJ_SHIFT) & 0xff, ver_id & 0xff);
return 0;
err:
--
2.20.1
