[PATCHv2 05/11] soc: ti: omap-prm: sync func clock status with resets

[Tero Kristo <t-kristo@xxxxxx>]

Hardware reset signals are tightly coupled with associated clocks, and
basically de-asserting a reset won't succeed properly if the clock is
not enabled, and vice-versa. Also, disabling a clock won't fully succeed
if the associated hardware resets are not asserted. Add status sync
functionality between these two for TI drivers so that the situations
can be handled properly without generating any timeouts.

Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
---
 drivers/soc/ti/omap_prm.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/soc/ti/omap_prm.c b/drivers/soc/ti/omap_prm.c
index 38998ce19c71..e876bad8f8d5 100644
--- a/drivers/soc/ti/omap_prm.c
+++ b/drivers/soc/ti/omap_prm.c
@@ -15,6 +15,8 @@
 #include <linux/platform_device.h>
 #include <linux/reset-controller.h>
 #include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/clk/ti.h>
 
 #include <linux/platform_data/ti-prm.h>
 
@@ -42,7 +44,9 @@ struct omap_reset_data {
 	struct reset_controller_dev rcdev;
 	struct omap_prm *prm;
 	struct clockdomain *clkdm;
+	struct clk *clk;
 	struct device *dev;
+	u32 mask;
 };
 
 #define to_omap_reset_data(p) container_of((p), struct omap_reset_data, rcdev)
@@ -102,6 +106,8 @@ static int omap_reset_assert(struct reset_controller_dev *rcdev,
 	v |= 1 << id;
 	writel_relaxed(v, reset->prm->base + reset->prm->data->rstctrl);
 
+	ti_clk_notify_resets(reset->clk, v == reset->mask);
+
 	return 0;
 }
 
@@ -163,9 +169,19 @@ static int omap_reset_deassert(struct reset_controller_dev *rcdev,
 	v &= ~(1 << id);
 	writel_relaxed(v, reset->prm->base + reset->prm->data->rstctrl);
 
+	ti_clk_notify_resets(reset->clk, v == reset->mask);
+
 	if (!has_rstst)
 		goto exit;
 
+	/* If associated clock is disabled, we can't poll completion status */
+	if (reset->clk) {
+		struct clk_hw *hw = __clk_get_hw(reset->clk);
+
+		if (!clk_hw_is_enabled(hw))
+			return ret;
+	}
+
 	/* wait for the status to be set */
 	while (1) {
 		v = readl_relaxed(reset->prm->base + reset->prm->data->rstst);
@@ -199,8 +215,10 @@ static int omap_prm_reset_init(struct platform_device *pdev,
 			       struct omap_prm *prm)
 {
 	struct omap_reset_data *reset;
+	const struct omap_rst_map *map;
 	struct ti_prm_platform_data *pdata = dev_get_platdata(&pdev->dev);
 	char buf[32];
+	u32 v;
 
 	/*
 	 * Check if we have controllable resets. If either rstctrl is non-zero
@@ -215,6 +233,10 @@ static int omap_prm_reset_init(struct platform_device *pdev,
 	    !pdata->clkdm_allow_idle)
 		return -EINVAL;
 
+	map = prm->data->rstmap;
+	if (!map)
+		return -EINVAL;
+
 	reset = devm_kzalloc(&pdev->dev, sizeof(*reset), GFP_KERNEL);
 	if (!reset)
 		return -ENOMEM;
@@ -224,6 +246,10 @@ static int omap_prm_reset_init(struct platform_device *pdev,
 	reset->rcdev.of_node = pdev->dev.of_node;
 	reset->rcdev.nr_resets = OMAP_MAX_RESETS;
 	reset->dev = &pdev->dev;
+	reset->clk = of_clk_get(pdev->dev.of_node, 0);
+
+	if (IS_ERR(reset->clk))
+		reset->clk = NULL;
 
 	reset->prm = prm;
 
@@ -234,6 +260,16 @@ static int omap_prm_reset_init(struct platform_device *pdev,
 	if (!reset->clkdm)
 		return -EINVAL;
 
+	while (map->rst >= 0) {
+		reset->mask |= BIT(map->rst);
+		map++;
+	}
+
+	if (reset->clk) {
+		v = readl_relaxed(reset->prm->base + reset->prm->data->rstctrl);
+		ti_clk_notify_resets(reset->clk, v == reset->mask);
+	}
+
 	return devm_reset_controller_register(&pdev->dev, &reset->rcdev);
 }
 
-- 
2.17.1

--
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