diff options
Diffstat (limited to 'drivers/char/hw_random/imx-rngc.c')
| -rw-r--r-- | drivers/char/hw_random/imx-rngc.c | 85 |
1 files changed, 69 insertions, 16 deletions
diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c index 30cf00f8e9a0..9c47e431ce90 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 @@ -31,6 +41,7 @@ #define RNGC_CTRL_MASK_ERROR 0x00000040 #define RNGC_CTRL_MASK_DONE 0x00000020 +#define RNGC_CTRL_AUTO_SEED 0x00000010 #define RNGC_STATUS_ERROR 0x00010000 #define RNGC_STATUS_FIFO_LEVEL_MASK 0x00000f00 @@ -100,15 +111,11 @@ static int imx_rngc_self_test(struct imx_rngc *rngc) writel(cmd | RNGC_CMD_SELF_TEST, rngc->base + RNGC_COMMAND); ret = wait_for_completion_timeout(&rngc->rng_op_done, RNGC_TIMEOUT); - if (!ret) { - imx_rngc_irq_mask_clear(rngc); + imx_rngc_irq_mask_clear(rngc); + if (!ret) return -ETIMEDOUT; - } - if (rngc->err_reg != 0) - return -EIO; - - return 0; + return rngc->err_reg ? -EIO : 0; } static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait) @@ -165,17 +172,17 @@ static irqreturn_t imx_rngc_irq(int irq, void *priv) static int imx_rngc_init(struct hwrng *rng) { struct imx_rngc *rngc = container_of(rng, struct imx_rngc, rng); - u32 cmd; + u32 cmd, ctrl; int ret; /* clear error */ cmd = readl(rngc->base + RNGC_COMMAND); writel(cmd | RNGC_CMD_CLR_ERR, rngc->base + RNGC_COMMAND); + imx_rngc_irq_unmask(rngc); + /* create seed, repeat while there is some statistical error */ do { - imx_rngc_irq_unmask(rngc); - /* seed creation */ cmd = readl(rngc->base + RNGC_COMMAND); writel(cmd | RNGC_CMD_SEED, rngc->base + RNGC_COMMAND); @@ -184,13 +191,42 @@ static int imx_rngc_init(struct hwrng *rng) RNGC_TIMEOUT); if (!ret) { - imx_rngc_irq_mask_clear(rngc); - return -ETIMEDOUT; + ret = -ETIMEDOUT; + goto err; } } while (rngc->err_reg == RNGC_ERROR_STATUS_STAT_ERR); - return rngc->err_reg ? -EIO : 0; + if (rngc->err_reg) { + ret = -EIO; + goto err; + } + + /* + * enable automatic seeding, the rngc creates a new seed automatically + * after serving 2^20 random 160-bit words + */ + ctrl = readl(rngc->base + RNGC_CONTROL); + ctrl |= RNGC_CTRL_AUTO_SEED; + writel(ctrl, rngc->base + RNGC_CONTROL); + + /* + * if initialisation was successful, we keep the interrupt + * unmasked until imx_rngc_cleanup is called + * we mask the interrupt ourselves if we return an error + */ + return 0; + +err: + imx_rngc_irq_mask_clear(rngc); + return ret; +} + +static void imx_rngc_cleanup(struct hwrng *rng) +{ + struct imx_rngc *rngc = container_of(rng, struct imx_rngc, rng); + + imx_rngc_irq_mask_clear(rngc); } static int imx_rngc_probe(struct platform_device *pdev) @@ -198,6 +234,8 @@ 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) @@ -223,6 +261,17 @@ 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) { @@ -235,6 +284,7 @@ static int imx_rngc_probe(struct platform_device *pdev) rngc->rng.name = pdev->name; rngc->rng.init = imx_rngc_init; rngc->rng.read = imx_rngc_read; + rngc->rng.cleanup = imx_rngc_cleanup; rngc->dev = &pdev->dev; platform_set_drvdata(pdev, rngc); @@ -244,18 +294,21 @@ static int imx_rngc_probe(struct platform_device *pdev) if (self_test) { ret = imx_rngc_self_test(rngc); if (ret) { - dev_err(rngc->dev, "FSL RNGC self test failed.\n"); + dev_err(rngc->dev, "self test failed\n"); goto err; } } ret = hwrng_register(&rngc->rng); if (ret) { - dev_err(&pdev->dev, "FSL RNGC registering failed (%d)\n", ret); + dev_err(&pdev->dev, "hwrng registration failed\n"); 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: |