Re: [PATCH v2 1/4] crypto: exynos - Support Exynos5250+ SoCs

Cc: Marek Szyprowski <m.szyprowski@samsung.com>, Bartlomiej Zolnierkiewicz <redacted>

Add support for PRNG in Exynos5250+ SoCs.

Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
---
 .../bindings/crypto/samsung,exynos-rng4.txt        |  4 ++-
 drivers/crypto/exynos-rng.c                        | 32 ++++++++++++++++++++--
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/crypto/samsung,exynos-rng4.txt b/Documentation/devicetree/bindings/crypto/samsung,exynos-rng4.txt
index 4ca8dd4d7e66..a13fbdb4bd88 100644
--- a/Documentation/devicetree/bindings/crypto/samsung,exynos-rng4.txt
+++ b/Documentation/devicetree/bindings/crypto/samsung,exynos-rng4.txt

@@ -2,7 +2,9 @@ Exynos Pseudo Random Number Generator

 Required properties:

-- compatible  : Should be "samsung,exynos4-rng".
+- compatible  : One of:
+                - "samsung,exynos4-rng" for Exynos4210 and Exynos4412
+                - "samsung,exynos5250-prng" for Exynos5250+
 - reg         : Specifies base physical address and size of the registers map.
 - clocks      : Phandle to clock-controller plus clock-specifier pair.
 - clock-names : "secss" as a clock name.

diff --git a/drivers/crypto/exynos-rng.c b/drivers/crypto/exynos-rng.c
index ed6ba796ad71..2f554b82f49f 100644
--- a/drivers/crypto/exynos-rng.c
+++ b/drivers/crypto/exynos-rng.c

@@ -22,12 +22,17 @@
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/module.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>

 #include <crypto/internal/rng.h>

 #define EXYNOS_RNG_CONTROL             0x0
 #define EXYNOS_RNG_STATUS              0x10
+
+#define EXYNOS_RNG_SEED_CONF           0x14
+#define EXYNOS_RNG_GEN_PRNG            BIT(1)
+
 #define EXYNOS_RNG_SEED_BASE           0x140
 #define EXYNOS_RNG_SEED(n)             (EXYNOS_RNG_SEED_BASE + (n * 0x4))
 #define EXYNOS_RNG_OUT_BASE            0x160

@@ -43,6 +48,12 @@
 #define EXYNOS_RNG_SEED_REGS           5
 #define EXYNOS_RNG_SEED_SIZE           (EXYNOS_RNG_SEED_REGS * 4)

+enum exynos_prng_type {
+       EXYNOS_PRNG_UNKNOWN = 0,
+       EXYNOS_PRNG_EXYNOS4,
+       EXYNOS_PRNG_EXYNOS5,
+};
+
 /*
  * Driver re-seeds itself with generated random numbers to increase
  * the randomness.

@@ -63,6 +74,7 @@ struct exynos_rng_ctx {
 /* Device associated memory */
 struct exynos_rng_dev {
        struct device                   *dev;
+       enum exynos_prng_type           type;
        void __iomem                    *mem;
        struct clk                      *clk;
        /* Generated numbers stored for seeding during resume */

@@ -160,8 +172,13 @@ static int exynos_rng_get_random(struct exynos_rng_dev *rng,
 {
        int retry = EXYNOS_RNG_WAIT_RETRIES;

-       exynos_rng_writel(rng, EXYNOS_RNG_CONTROL_START,
-                         EXYNOS_RNG_CONTROL);
+       if (rng->type == EXYNOS_PRNG_EXYNOS4) {
+               exynos_rng_writel(rng, EXYNOS_RNG_CONTROL_START,
+                                 EXYNOS_RNG_CONTROL);
+       } else if (rng->type == EXYNOS_PRNG_EXYNOS5) {
+               exynos_rng_writel(rng, EXYNOS_RNG_GEN_PRNG,
+                                 EXYNOS_RNG_SEED_CONF);
+       }

        while (!(exynos_rng_readl(rng,
                        EXYNOS_RNG_STATUS) & EXYNOS_RNG_STATUS_RNG_DONE) && --retry)

@@ -279,6 +296,13 @@ static int exynos_rng_probe(struct platform_device *pdev)
        if (!rng)
                return -ENOMEM;

+       rng->type = (enum exynos_prng_type)of_device_get_match_data(&pdev->dev);
+       if (rng->type != EXYNOS_PRNG_EXYNOS4 &&
+           rng->type != EXYNOS_PRNG_EXYNOS5) {
+               dev_err(&pdev->dev, "Unsupported PRNG type: %d", rng->type);
+               return -ENOTSUPP;
+       }
+