Merge tag 'samsung-clk-6.20' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux into clk-samsung

Pull Samsung clk driver updates from Krzysztof Kozlowski:

1. Add new clock controllers:
   - MFD for ExynosAutov920 SoC,
   - Display Process Unit (DPU) for Google GS101 SoC.

2. Implement automatic clock gating mode (HWACG) for Google GS101 SoC
   clock controllers (but also used on almost all modern Exynos SoC),
   opposed to currently used mode - manual mode.

Background on HW automatic clock gating from Peter Griffin in cover letter:

This series addresses an issue with Samsung Exynos based upstream clock driver
whereby the upstream clock driver sets all the clock gates into "manual mode"
(which uses a bit that is documented as reserved in the gate registers).

Another issue with the current "manual clock gating" approach upstream is
there are many bus/interconnect clocks whose relationships to the IPs
are not well documented or defined in the specs. When adding a new CMU until
now we have tried to label these clocks appropriately with CLK_IS_CRITICAL and
CLK_IGNORE_UNUSED but doing so is both error prone and time consuming. If
your lucky disabling a critical bus clock causes an immediate hang. Other
clocks however aren't so obvious and show up through random instability
some period of time later.

Fortunately each CMU (at least on newer Exynos) provides a "hardware
automatic clock gating" HWACG feature that is used by the downstream
Samsung clock drivers. Hardware automatic clock gating uses a hardware
interface between the CMU and IP to control all clocks required by the
IP. This interface is called Q-channel, and is part of the Arm AMBA low
power interface specification [1].

The advantage of using this Qchannel hardware interface for
enabling/disabling the clocks is that it takes care of all clocks
(including bus/interconnect) ones for the IP automatically thereby reducing
the dynamic power.

Whilst each clock component (GATE, MUX, DIV, QCH etc) has a HWACG enable
bit there are also some "global enable override" bits for the entire CMU in
the CMU_CONTROLLER_OPTION register.

This series makes use of those "global enable" override bits to enable auto
clock mode for the entire CMU and every component within it. Through
experimentation we can see that setting the "manual mode" reserved gate bit
on a particular gate register overides the global enable bits. So the code
is updated accordingly not to do that.

Auto clock mode has been implemented as a "opt in" by setting a new
auto_clock_gate flag in the CMU static data. The intention is existing
platforms in manual mode should not be effected by any of these changes.

If auto_clock_mode flag is set and the option_offset field is specified
then the global enable override bits will be written for the
CMU (to avoid relying on any prior bootstage configuration). Again if auto
mode is enabled the code no longer sets MANUAL and clears HWACG bits on
each gate register.

To ensure compatibility with older DTs (that specified an incorrect CMU
size) the resource size is checked and the driver falls back to manual
clock gate mode in such cases. As the CLK_IGNORE_UNUSED and CLK_IS_CRITICAL
flags are required for manual clock gate mode, the patch removing these
flags has been dropped from v2. I tested with an old DT and we successfully
switch to manual clock gate mode and the system correctly boots.

To have dynamic root clock gating (drcg) of bus components and memclk
enabled, it is required to set the bus_component_drcg and memclk registers
in the correspondingly named sysreg controller. If auto clock mode is
enabled the clock driver will now attempt to get the sysreg syscon via the
samsung,sysreg property (as used by other Exynos drivers upstream) and set
the registers accordingly. The suspend/resume code paths are also updated
to handle saving/restoring registers using a regmap. Note cmu_top is an
exception and does not have a corresondingly named sysreg_top.

As all clock gates are currently exposed in the gs101 drivers and DT, we
continue to register all of these gates in auto clock mode, but with some new
samsung_auto_clk_gate_ops. As clk enable and clk disable are now handled by
Q-channel interface the .enable and .disable implementations are
no-ops. However by using some CMU qchannel debug registers we can report
the current clock status (enabled or disabled) of every clock gate in the
system. This has the nice effect of still being able to dump the entire
clock tree from /sys/kernel/debug/clk/clk_summary and see a live view of
every auto clock in the system.

With the infrastructure in place, all the CMUs registered in clk-gs101 are
now updated to enable auto clock mode. From dumping
/sys/kernel/debug/clk/clk_summary it is possible to see that after enabling
auto clock mode approximately 305 clocks are enabled, and 299 are now
disabled. This number goes up and down a bit by 3-5 clocks just on a idle
system sat at a console.

With auto clock mode enabled it is now also possible to boot without the
clk_ignore_unused kernel command line property for the first time!

For future CMUs in gs101 I propose we continue to expose all gates, but
register the CMU in "auto mode". For new device drivers or updates to
existing dt bindings related to clocks to support gs101 I suggest we only
use the "obviously correct" clock(s). By "obviously correct" I mean a clock
has the IP name in the clock register name, but not try to deduce other
obsucurely named bus/interconnect clocks which will now all be handled
automatically. Note it is still possible to test whether the "obviously
correct" clock is indeed correct by putting the individual gate in manual
mode and disabling the clock (e.g. by using devmem).

* tag 'samsung-clk-6.20' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux:
  clk: samsung: gs101: add support for Display Process Unit (DPU) clocks
  dt-bindings: samsung: exynos-sysreg: add gs101 dpu compatible
  dt-bindings: clock: google,gs101-clock: Add DPU clock management unit
  dt-bindings: clock: google,gs101-clock: fix alphanumeric ordering
  clk: samsung: fix sysreg save/restore when PM is enabled for CMU
  clk: samsung: avoid warning message on legacy Exynos (auto clock gating)
  clk: samsung: gs101: Enable auto_clock_gate mode for each gs101 CMU
  clk: samsung: Implement automatic clock gating mode for CMUs
  dt-bindings: clock: google,gs101-clock: add samsung,sysreg property as required
  clk: samsung: exynosautov920: add clock support
  dt-bindings: clock: exynosautov920: add MFD clock definitions

Author: bebarino

Documentation/devicetree/bindings/clock/google,gs101-clock.yaml

@@ -29,9 +29,10 @@ properties:
     enum:
       - google,gs101-cmu-top
       - google,gs101-cmu-apm
-      - google,gs101-cmu-misc
+      - google,gs101-cmu-dpu
       - google,gs101-cmu-hsi0
       - google,gs101-cmu-hsi2
+      - google,gs101-cmu-misc
       - google,gs101-cmu-peric0
       - google,gs101-cmu-peric1
 
@@ -52,6 +53,11 @@ properties:
   reg:
     maxItems: 1
 
+  samsung,sysreg:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to system registers interface.
+
 required:
   - compatible
   - "#clock-cells"
@@ -77,6 +83,24 @@ allOf:
           items:
             - const: oscclk
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: google,gs101-cmu-dpu
+
+    then:
+      properties:
+        clocks:
+          items:
+            - description: External reference clock (24.576 MHz)
+            - description: DPU bus clock (from CMU_TOP)
+
+        clock-names:
+          items:
+            - const: oscclk
+            - const: bus
+
   - if:
       properties:
         compatible:
@@ -166,6 +190,18 @@ allOf:
             - const: bus
             - const: ip
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: google,gs101-cmu-top
+    then:
+      properties:
+        samsung,sysreg: false
+    else:
+      required:
+        - samsung,sysreg
+
 additionalProperties: false
 
 examples:
@@ -175,7 +211,7 @@ examples:
 
     cmu_top: clock-controller@1e080000 {
         compatible = "google,gs101-cmu-top";
-        reg = <0x1e080000 0x8000>;
+        reg = <0x1e080000 0x10000>;
         #clock-cells = <1>;
         clocks = <&ext_24_5m>;
         clock-names = "oscclk";

Documentation/devicetree/bindings/clock/samsung,exynosautov920-clock.yaml

@@ -40,6 +40,7 @@ properties:
       - samsung,exynosautov920-cmu-hsi2
       - samsung,exynosautov920-cmu-m2m
       - samsung,exynosautov920-cmu-mfc
+      - samsung,exynosautov920-cmu-mfd
       - samsung,exynosautov920-cmu-misc
       - samsung,exynosautov920-cmu-peric0
       - samsung,exynosautov920-cmu-peric1
@@ -268,6 +269,24 @@ allOf:
             - const: mfc
             - const: wfd
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: samsung,exynosautov920-cmu-mfd
+
+    then:
+      properties:
+        clocks:
+          items:
+            - description: External reference clock (38.4 MHz)
+            - description: CMU_MFD NOC clock (from CMU_TOP)
+
+        clock-names:
+          items:
+            - const: oscclk
+            - const: noc
+
 required:
   - compatible
   - "#clock-cells"

Documentation/devicetree/bindings/soc/samsung/samsung,exynos-sysreg.yaml

@@ -15,6 +15,7 @@ properties:
       - items:
           - enum:
               - google,gs101-apm-sysreg
+              - google,gs101-dpu-sysreg
               - google,gs101-hsi0-sysreg
               - google,gs101-hsi2-sysreg
               - google,gs101-misc-sysreg
@@ -92,6 +93,7 @@ allOf:
         compatible:
           contains:
             enum:
+              - google,gs101-dpu-sysreg
               - google,gs101-hsi0-sysreg
               - google,gs101-hsi2-sysreg
               - google,gs101-misc-sysreg

drivers/clk/samsung/clk-exynos-arm64.c

@@ -24,6 +24,16 @@
 #define GATE_MANUAL		BIT(20)
 #define GATE_ENABLE_HWACG	BIT(28)
 
+/* Option register bits */
+#define OPT_EN_MEM_PWR_GATING		BIT(24)
+#define OPT_EN_AUTO_GATING		BIT(28)
+#define OPT_EN_PWR_MANAGEMENT		BIT(29)
+#define OPT_EN_LAYER2_CTRL		BIT(30)
+#define OPT_EN_DBG			BIT(31)
+
+#define CMU_OPT_GLOBAL_EN_AUTO_GATING	(OPT_EN_DBG | OPT_EN_LAYER2_CTRL | \
+	OPT_EN_PWR_MANAGEMENT | OPT_EN_AUTO_GATING | OPT_EN_MEM_PWR_GATING)
+
 /* PLL_CONx_PLL register offsets range */
 #define PLL_CON_OFF_START	0x100
 #define PLL_CON_OFF_END		0x600
@@ -37,6 +47,8 @@ struct exynos_arm64_cmu_data {
 	unsigned int nr_clk_save;
 	const struct samsung_clk_reg_dump *clk_suspend;
 	unsigned int nr_clk_suspend;
+	struct samsung_clk_reg_dump *clk_sysreg_save;
+	unsigned int nr_clk_sysreg;
 
 	struct clk *clk;
 	struct clk **pclks;
@@ -76,19 +88,41 @@ static void __init exynos_arm64_init_clocks(struct device_node *np,
 	const unsigned long *reg_offs = cmu->clk_regs;
 	size_t reg_offs_len = cmu->nr_clk_regs;
 	void __iomem *reg_base;
+	bool init_auto;
 	size_t i;
 
 	reg_base = of_iomap(np, 0);
 	if (!reg_base)
 		panic("%s: failed to map registers\n", __func__);
 
+	/* ensure compatibility with older DTs */
+	if (cmu->auto_clock_gate && samsung_is_auto_capable(np))
+		init_auto = true;
+	else
+		init_auto = false;
+
+	if (cmu->option_offset && init_auto) {
+		/*
+		 * Enable the global automatic mode for the entire CMU.
+		 * This overrides the individual HWACG bits in each of the
+		 * individual gate, mux and qch registers.
+		 */
+		writel(CMU_OPT_GLOBAL_EN_AUTO_GATING,
+		       reg_base + cmu->option_offset);
+	}
+
 	for (i = 0; i < reg_offs_len; ++i) {
 		void __iomem *reg = reg_base + reg_offs[i];
 		u32 val;
 
 		if (cmu->manual_plls && is_pll_con1_reg(reg_offs[i])) {
 			writel(PLL_CON1_MANUAL, reg);
-		} else if (is_gate_reg(reg_offs[i])) {
+		} else if (is_gate_reg(reg_offs[i]) && !init_auto) {
+			/*
+			 * Setting GATE_MANUAL bit (which is described in TRM as
+			 * reserved!) overrides the global CMU automatic mode
+			 * option.
+			 */
 			val = readl(reg);
 			val |= GATE_MANUAL;
 			val &= ~GATE_ENABLE_HWACG;
@@ -140,40 +174,60 @@ static int __init exynos_arm64_cmu_prepare_pm(struct device *dev,
 		const struct samsung_cmu_info *cmu)
 {
 	struct exynos_arm64_cmu_data *data = dev_get_drvdata(dev);
-	int i;
+	int i, ret;
 
 	data->clk_save = samsung_clk_alloc_reg_dump(cmu->clk_regs,
 						    cmu->nr_clk_regs);
 	if (!data->clk_save)
 		return -ENOMEM;
 
 	data->nr_clk_save = cmu->nr_clk_regs;
+
+	if (cmu->nr_sysreg_clk_regs) {
+		data->clk_sysreg_save =
+			samsung_clk_alloc_reg_dump(cmu->sysreg_clk_regs,
+						   cmu->nr_sysreg_clk_regs);
+		if (!data->clk_sysreg_save) {
+			ret = -ENOMEM;
+			goto free_clk_save;
+		}
+
+		data->nr_clk_sysreg = cmu->nr_sysreg_clk_regs;
+	}
+
 	data->clk_suspend = cmu->suspend_regs;
 	data->nr_clk_suspend = cmu->nr_suspend_regs;
+
 	data->nr_pclks = of_clk_get_parent_count(dev->of_node);
 	if (!data->nr_pclks)
 		return 0;
 
 	data->pclks = devm_kcalloc(dev, sizeof(struct clk *), data->nr_pclks,
 				   GFP_KERNEL);
 	if (!data->pclks) {
-		kfree(data->clk_save);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto free_sysreg_save;
 	}
 
 	for (i = 0; i < data->nr_pclks; i++) {
 		struct clk *clk = of_clk_get(dev->of_node, i);
 
 		if (IS_ERR(clk)) {
-			kfree(data->clk_save);
 			while (--i >= 0)
 				clk_put(data->pclks[i]);
-			return PTR_ERR(clk);
+			ret = PTR_ERR(clk);
+			goto free_sysreg_save;
 		}
 		data->pclks[i] = clk;
 	}
 
 	return 0;
+
+free_sysreg_save:
+	kfree(data->clk_sysreg_save);
+free_clk_save:
+	kfree(data->clk_save);
+	return ret;
 }
 
 /**
@@ -210,16 +264,16 @@ void __init exynos_arm64_register_cmu(struct device *dev,
 /**
  * exynos_arm64_register_cmu_pm - Register Exynos CMU domain with PM support
  *
- * @pdev:	Platform device object
- * @set_manual:	If true, set gate clocks to manual mode
+ * @pdev:		Platform device object
+ * @init_clk_regs:	If true, initialize CMU registers
  *
  * It's a version of exynos_arm64_register_cmu() with PM support. Should be
  * called from probe function of platform driver.
  *
  * Return: 0 on success, or negative error code on error.
  */
 int __init exynos_arm64_register_cmu_pm(struct platform_device *pdev,
-					bool set_manual)
+					bool init_clk_regs)
 {
 	const struct samsung_cmu_info *cmu;
 	struct device *dev = &pdev->dev;
@@ -249,7 +303,7 @@ int __init exynos_arm64_register_cmu_pm(struct platform_device *pdev,
 		dev_err(dev, "%s: could not enable bus clock %s; err = %d\n",
 		       __func__, cmu->clk_name, ret);
 
-	if (set_manual)
+	if (init_clk_regs)
 		exynos_arm64_init_clocks(np, cmu);
 
 	reg_base = devm_platform_ioremap_resource(pdev, 0);
@@ -268,8 +322,10 @@ int __init exynos_arm64_register_cmu_pm(struct platform_device *pdev,
 	pm_runtime_set_active(dev);
 	pm_runtime_enable(dev);
 
-	samsung_cmu_register_clocks(data->ctx, cmu);
+	samsung_cmu_register_clocks(data->ctx, cmu, np);
 	samsung_clk_of_add_provider(dev->of_node, data->ctx);
+	/* sysreg DT nodes reference a clock in this CMU */
+	samsung_en_dyn_root_clk_gating(np, data->ctx, cmu, true);
 	pm_runtime_put_sync(dev);
 
 	return 0;
@@ -280,14 +336,17 @@ int exynos_arm64_cmu_suspend(struct device *dev)
 	struct exynos_arm64_cmu_data *data = dev_get_drvdata(dev);
 	int i;
 
-	samsung_clk_save(data->ctx->reg_base, data->clk_save,
+	samsung_clk_save(data->ctx->reg_base, NULL, data->clk_save,
 			 data->nr_clk_save);
 
+	samsung_clk_save(NULL, data->ctx->sysreg, data->clk_sysreg_save,
+			 data->nr_clk_sysreg);
+
 	for (i = 0; i < data->nr_pclks; i++)
 		clk_prepare_enable(data->pclks[i]);
 
 	/* For suspend some registers have to be set to certain values */
-	samsung_clk_restore(data->ctx->reg_base, data->clk_suspend,
+	samsung_clk_restore(data->ctx->reg_base, NULL, data->clk_suspend,
 			    data->nr_clk_suspend);
 
 	for (i = 0; i < data->nr_pclks; i++)
@@ -308,9 +367,14 @@ int exynos_arm64_cmu_resume(struct device *dev)
 	for (i = 0; i < data->nr_pclks; i++)
 		clk_prepare_enable(data->pclks[i]);
 
-	samsung_clk_restore(data->ctx->reg_base, data->clk_save,
+	samsung_clk_restore(data->ctx->reg_base, NULL, data->clk_save,
 			    data->nr_clk_save);
 
+	if (data->ctx->sysreg)
+		samsung_clk_restore(NULL, data->ctx->sysreg,
+				    data->clk_sysreg_save,
+				    data->nr_clk_sysreg);
+
 	for (i = 0; i < data->nr_pclks; i++)
 		clk_disable_unprepare(data->pclks[i]);
 

drivers/clk/samsung/clk-exynos4.c

@@ -1361,12 +1361,12 @@ static void __init exynos4_clk_init(struct device_node *np,
 					ARRAY_SIZE(exynos4x12_plls));
 	}
 
-	samsung_cmu_register_clocks(ctx, &cmu_info_exynos4);
+	samsung_cmu_register_clocks(ctx, &cmu_info_exynos4, np);
 
 	if (exynos4_soc == EXYNOS4210) {
-		samsung_cmu_register_clocks(ctx, &cmu_info_exynos4210);
+		samsung_cmu_register_clocks(ctx, &cmu_info_exynos4210, np);
 	} else {
-		samsung_cmu_register_clocks(ctx, &cmu_info_exynos4x12);
+		samsung_cmu_register_clocks(ctx, &cmu_info_exynos4x12, np);
 		if (soc == EXYNOS4412)
 			samsung_clk_register_cpu(ctx, exynos4412_cpu_clks,
 					ARRAY_SIZE(exynos4412_cpu_clks));
@@ -1378,15 +1378,15 @@ static void __init exynos4_clk_init(struct device_node *np,
 	if (soc == EXYNOS4212 || soc == EXYNOS4412)
 		exynos4x12_core_down_clock();
 
-	samsung_clk_extended_sleep_init(reg_base,
+	samsung_clk_extended_sleep_init(reg_base, NULL,
 			exynos4_clk_regs, ARRAY_SIZE(exynos4_clk_regs),
 			src_mask_suspend, ARRAY_SIZE(src_mask_suspend));
 	if (exynos4_soc == EXYNOS4210)
-		samsung_clk_extended_sleep_init(reg_base,
+		samsung_clk_extended_sleep_init(reg_base, NULL,
 		    exynos4210_clk_save, ARRAY_SIZE(exynos4210_clk_save),
 		    src_mask_suspend_e4210, ARRAY_SIZE(src_mask_suspend_e4210));
 	else
-		samsung_clk_sleep_init(reg_base, exynos4x12_clk_save,
+		samsung_clk_sleep_init(reg_base, NULL, exynos4x12_clk_save,
 				       ARRAY_SIZE(exynos4x12_clk_save));
 
 	samsung_clk_of_add_provider(np, ctx);

drivers/clk/samsung/clk-exynos4412-isp.c

@@ -94,7 +94,7 @@ static int __maybe_unused exynos4x12_isp_clk_suspend(struct device *dev)
 {
 	struct samsung_clk_provider *ctx = dev_get_drvdata(dev);
 
-	samsung_clk_save(ctx->reg_base, exynos4x12_save_isp,
+	samsung_clk_save(ctx->reg_base, NULL, exynos4x12_save_isp,
 			 ARRAY_SIZE(exynos4x12_clk_isp_save));
 	return 0;
 }
@@ -103,7 +103,7 @@ static int __maybe_unused exynos4x12_isp_clk_resume(struct device *dev)
 {
 	struct samsung_clk_provider *ctx = dev_get_drvdata(dev);
 
-	samsung_clk_restore(ctx->reg_base, exynos4x12_save_isp,
+	samsung_clk_restore(ctx->reg_base, NULL, exynos4x12_save_isp,
 			    ARRAY_SIZE(exynos4x12_clk_isp_save));
 	return 0;
 }

drivers/clk/samsung/clk-exynos5250.c

@@ -854,7 +854,7 @@ static void __init exynos5250_clk_init(struct device_node *np)
 		PWR_CTRL2_CORE2_UP_RATIO | PWR_CTRL2_CORE1_UP_RATIO);
 	__raw_writel(tmp, reg_base + PWR_CTRL2);
 
-	samsung_clk_sleep_init(reg_base, exynos5250_clk_regs,
+	samsung_clk_sleep_init(reg_base, NULL, exynos5250_clk_regs,
 			       ARRAY_SIZE(exynos5250_clk_regs));
 	exynos5_subcmus_init(ctx, ARRAY_SIZE(exynos5250_subcmus),
 			     exynos5250_subcmus);