[PATCH v3 01/11] clk: Allow force setting clock defaults before relocation

[Sean Anderson <seanga2@gmail.com>]

Since 291da96b8e ("clk: Allow clock defaults to be set during re-reloc
state for SPL only") it has been impossible to set clock defaults before
relocation. This is annoying on boards without SPL, since there is no way
to set clock defaults before U-Boot proper. In particular, the aisram rate
must be changed before relocation on the K210, since U-Boot will hang if we
try and change the rate while we are using aisram.

To get around this, extend the stage parameter to allow force setting
defaults, even if they would be otherwise postponed for later. A device
tree property was decided against because of the concerns in the original
commit thread about the overhead of repeatedly parsing the device tree.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---

Changes in v3:
- Always define clk_defaults_stage, even if clk_set_defaults is a dummy

Changes in v2:
- Convert stage to enum

 drivers/clk/clk-uclass.c          | 27 +++++++++++++++++----------
 drivers/clk/rockchip/clk_rk3308.c |  2 +-
 drivers/core/device.c             |  2 +-
 drivers/net/gmac_rockchip.c       |  2 +-
 include/clk.h                     | 30 ++++++++++++++++++++++++++----
 5 files changed, 46 insertions(+), 17 deletions(-)

diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
index 53e7be764d..25b6a41855 100644
--- a/drivers/clk/clk-uclass.c
+++ b/drivers/clk/clk-uclass.c
@@ -207,7 +207,8 @@ static struct clk *clk_set_default_get_by_id(struct clk *clk)
 	return c;
 }
 
-static int clk_set_default_parents(struct udevice *dev, int stage)
+static int clk_set_default_parents(struct udevice *dev,
+				   enum clk_defaults_stage stage)
 {
 	struct clk clk, parent_clk, *c, *p;
 	int index;
@@ -251,10 +252,10 @@ static int clk_set_default_parents(struct udevice *dev, int stage)
 		 * It cannot be done right now but need to wait after the
 		 * device is probed
 		 */
-		if (stage == 0 && clk.dev == dev)
+		if (stage == CLK_DEFAULTS_PRE && clk.dev == dev)
 			continue;
 
-		if (stage > 0 && clk.dev != dev)
+		if (stage != CLK_DEFAULTS_PRE && clk.dev != dev)
 			/* do not setup twice the parent clocks */
 			continue;
 
@@ -280,7 +281,8 @@ static int clk_set_default_parents(struct udevice *dev, int stage)
 	return 0;
 }
 
-static int clk_set_default_rates(struct udevice *dev, int stage)
+static int clk_set_default_rates(struct udevice *dev,
+				 enum clk_defaults_stage stage)
 {
 	struct clk clk, *c;
 	int index;
@@ -320,10 +322,10 @@ static int clk_set_default_rates(struct udevice *dev, int stage)
 		 * It cannot be done right now but need to wait after the
 		 * device is probed
 		 */
-		if (stage == 0 && clk.dev == dev)
+		if (stage == CLK_DEFAULTS_PRE && clk.dev == dev)
 			continue;
 
-		if (stage > 0 && clk.dev != dev)
+		if (stage != CLK_DEFAULTS_PRE && clk.dev != dev)
 			/* do not setup twice the parent clocks */
 			continue;
 
@@ -346,16 +348,21 @@ fail:
 	return ret;
 }
 
-int clk_set_defaults(struct udevice *dev, int stage)
+int clk_set_defaults(struct udevice *dev, enum clk_defaults_stage stage)
 {
 	int ret;
 
 	if (!dev_has_ofnode(dev))
 		return 0;
 
-	/* If this not in SPL and pre-reloc state, don't take any action. */
+	/*
+	 * To avoid setting defaults twice, don't set them before relocation.
+	 * However, still set them for SPL. And still set them if explicitly
+	 * asked.
+	 */
 	if (!(IS_ENABLED(CONFIG_SPL_BUILD) || (gd->flags & GD_FLG_RELOC)))
-		return 0;
+		if (stage != CLK_DEFAULTS_POST_FORCE)
+			return 0;
 
 	debug("%s(%s)\n", __func__, dev_read_name(dev));
 
@@ -805,7 +812,7 @@ int clk_uclass_post_probe(struct udevice *dev)
 	 * where the DT is used to setup default parents and rates
 	 * using assigned-clocks
 	 */
-	clk_set_defaults(dev, 1);
+	clk_set_defaults(dev, CLK_DEFAULTS_POST);
 
 	return 0;
 }
diff --git a/drivers/clk/rockchip/clk_rk3308.c b/drivers/clk/rockchip/clk_rk3308.c
index 5a838b9e9a..5248e59685 100644
--- a/drivers/clk/rockchip/clk_rk3308.c
+++ b/drivers/clk/rockchip/clk_rk3308.c
@@ -1014,7 +1014,7 @@ static int rk3308_clk_probe(struct udevice *dev)
 	rk3308_clk_init(dev);
 
 	/* Process 'assigned-{clocks/clock-parents/clock-rates}' properties */
-	ret = clk_set_defaults(dev, 1);
+	ret = clk_set_defaults(dev, CLK_DEFAULTS_POST);
 	if (ret)
 		debug("%s clk_set_defaults failed %d\n", __func__, ret);
 
diff --git a/drivers/core/device.c b/drivers/core/device.c
index cb960f8ec4..9f1400768d 100644
--- a/drivers/core/device.c
+++ b/drivers/core/device.c
@@ -561,7 +561,7 @@ int device_probe(struct udevice *dev)
 		 * Process 'assigned-{clocks/clock-parents/clock-rates}'
 		 * properties
 		 */
-		ret = clk_set_defaults(dev, 0);
+		ret = clk_set_defaults(dev, CLK_DEFAULTS_PRE);
 		if (ret)
 			goto fail;
 	}
diff --git a/drivers/net/gmac_rockchip.c b/drivers/net/gmac_rockchip.c
index f909660484..04008d2b19 100644
--- a/drivers/net/gmac_rockchip.c
+++ b/drivers/net/gmac_rockchip.c
@@ -565,7 +565,7 @@ static int gmac_rockchip_probe(struct udevice *dev)
 	ulong rate;
 	int ret;
 
-	ret = clk_set_defaults(dev, 0);
+	ret = clk_set_defaults(dev, CLK_DEFAULTS_PRE);
 	if (ret)
 		debug("%s clk_set_defaults failed %d\n", __func__, ret);
 
diff --git a/include/clk.h b/include/clk.h
index ca6b85fa6f..f3c88fe68a 100644
--- a/include/clk.h
+++ b/include/clk.h
@@ -277,19 +277,41 @@ static inline int clk_release_all(struct clk *clk, int count)
 }
 #endif
 
+/**
+ * enum clk_defaults_stage - What stage clk_set_defaults() is called at
+ * @CLK_DEFAULTS_PRE: Called before probe. Setting of defaults for clocks owned
+ *                    by this clock driver will be defered until after probing.
+ * @CLK_DEFAULTS_POST: Called after probe. Only defaults for clocks owned by
+ *                     this clock driver will be set.
+ * @CLK_DEFAULTS_POST_FORCE: Called after probe, and always set defaults, even
+ *                           before relocation. Usually, defaults are not set
+ *                           pre-relocation to avoid setting them twice (when
+ *                           the device is probed again post-relocation). This
+ *                           may incur a performance cost as device tree
+ *                           properties must be parsed for a second time.
+ *                           However, when not using SPL, pre-relocation may be
+ *                           the only time we can set defaults for some clocks
+ *                           (such as those used for the RAM we will relocate
+ *                           into).
+ */
+enum clk_defaults_stage {
+	CLK_DEFAULTS_PRE = 0,
+	CLK_DEFAULTS_POST = 1,
+	CLK_DEFAULTS_POST_FORCE,
+};
+
 #if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) && \
 	CONFIG_IS_ENABLED(CLK)
+
 /**
  * clk_set_defaults - Process 'assigned-{clocks/clock-parents/clock-rates}'
  *                    properties to configure clocks
  *
  * @dev:        A device to process (the ofnode associated with this device
  *              will be processed).
- * @stage:	A integer. 0 indicates that this is called before the device
- *		is probed. 1 indicates that this is called just after the
- *		device has been probed
+ * @stage:	The stage of the probing process this function is called during.
  */
-int clk_set_defaults(struct udevice *dev, int stage);
+int clk_set_defaults(struct udevice *dev, enum clk_defaults_stage stage);
 #else
 static inline int clk_set_defaults(struct udevice *dev, int stage)
 {
-- 
2.31.0