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

[Patrick Delaunay]

From: Lionel Debieve <lionel.debieve at 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.debieve at foss.st.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay at 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