[PATCH 02/10] rng: stm32mp1_rng: add conditional reset feature for STM32MP13x

[Patrick Delaunay]

From: Lionel Debieve <lionel.debi...@foss.st.com>

New IP adds a conditional reset that impact the clock
error management. It is now linked to a new compatible.

Signed-off-by: Lionel Debieve <lionel.debi...@foss.st.com>
Signed-off-by: Patrick Delaunay <patrick.delau...@foss.st.com>
---

(no changes since v1)

 drivers/rng/stm32mp1_rng.c | 61 +++++++++++++++++++++++++++++---------
 1 file changed, 47 insertions(+), 14 deletions(-)

diff --git a/drivers/rng/stm32mp1_rng.c b/drivers/rng/stm32mp1_rng.c
index 8ea00e3e890..89da78c6c8b 100644
--- a/drivers/rng/stm32mp1_rng.c
+++ b/drivers/rng/stm32mp1_rng.c
@@ -18,22 +18,28 @@
 #include <linux/iopoll.h>
 #include <linux/kernel.h>
 
-#define RNG_CR 0x00
-#define RNG_CR_RNGEN BIT(2)
-#define RNG_CR_CED BIT(5)
+#define RNG_CR         0x00
+#define RNG_CR_RNGEN   BIT(2)
+#define RNG_CR_CED     BIT(5)
+#define RNG_CR_CONDRST BIT(30)
 
-#define RNG_SR 0x04
-#define RNG_SR_SEIS BIT(6)
-#define RNG_SR_CEIS BIT(5)
-#define RNG_SR_SECS BIT(2)
-#define RNG_SR_DRDY BIT(0)
+#define RNG_SR         0x04
+#define RNG_SR_SEIS    BIT(6)
+#define RNG_SR_CEIS    BIT(5)
+#define RNG_SR_SECS    BIT(2)
+#define RNG_SR_DRDY    BIT(0)
 
-#define RNG_DR 0x08
+#define RNG_DR         0x08
+
+struct stm32_rng_data {
+       bool has_cond_reset;
+};
 
 struct stm32_rng_plat {
        fdt_addr_t base;
        struct clk clk;
        struct reset_ctl rst;
+       const struct stm32_rng_data *data;
 };
 
 static int stm32_rng_read(struct udevice *dev, void *data, size_t len)
@@ -83,18 +89,36 @@ static int stm32_rng_read(struct udevice *dev, void *data, 
size_t len)
 static int stm32_rng_init(struct stm32_rng_plat *pdata)
 {
        int err;
+       u32 cr, sr;
 
        err = clk_enable(&pdata->clk);
        if (err)
                return err;
 
+       cr = readl(pdata->base + RNG_CR);
+
        /* Disable CED */
-       writel(RNG_CR_RNGEN | RNG_CR_CED, pdata->base + RNG_CR);
+       cr |= RNG_CR_CED;
+       if (pdata->data->has_cond_reset) {
+               cr |= RNG_CR_CONDRST;
+               writel(cr, pdata->base + RNG_CR);
+               cr &= ~RNG_CR_CONDRST;
+               writel(cr, pdata->base + RNG_CR);
+               err = readl_poll_timeout(pdata->base + RNG_CR, cr,
+                                        (!(cr & RNG_CR_CONDRST)), 10000);
+               if (err)
+                       return err;
+       }
 
        /* clear error indicators */
        writel(0, pdata->base + RNG_SR);
 
-       return 0;
+       cr |= RNG_CR_RNGEN;
+       writel(cr, pdata->base + RNG_CR);
+
+       err = readl_poll_timeout(pdata->base + RNG_SR, sr,
+                                sr & RNG_SR_DRDY, 10000);
+       return err;
 }
 
 static int stm32_rng_cleanup(struct stm32_rng_plat *pdata)
@@ -108,6 +132,8 @@ static int stm32_rng_probe(struct udevice *dev)
 {
        struct stm32_rng_plat *pdata = dev_get_plat(dev);
 
+       pdata->data = (struct stm32_rng_data *)dev_get_driver_data(dev);
+
        reset_assert(&pdata->rst);
        udelay(20);
        reset_deassert(&pdata->rst);
@@ -146,10 +172,17 @@ static const struct dm_rng_ops stm32_rng_ops = {
        .read = stm32_rng_read,
 };
 
+static const struct stm32_rng_data stm32mp13_rng_data = {
+       .has_cond_reset = true,
+};
+
+static const struct stm32_rng_data stm32_rng_data = {
+       .has_cond_reset = false,
+};
+
 static const struct udevice_id stm32_rng_match[] = {
-       {
-               .compatible = "st,stm32-rng",
-       },
+       {.compatible = "st,stm32mp13-rng", .data = (ulong)&stm32mp13_rng_data},
+       {.compatible = "st,stm32-rng", .data = (ulong)&stm32_rng_data},
        {},
 };
 
-- 
2.25.1