[PATCH v4 0/4] Modify MxL's CGU clk driver to make it secure boot compatible

[PATCH v4 0/4] Modify MxL's CGU clk driver to make it secure boot compatible

[Rahul Tanwar]

MxL's CGU driver was found to be lacking below required features. Add these
required lacking features:

1. Since it is a core driver, it has to conform to secure boot & secure
   access architecture. In order for the register accesses to be secure
   access compliant, it needs regmap support as per our security architecture.
   Hence, replace direct read/writel with regmap based IO. Also remove
   redundant spinlocks from the driver as they are no longer necessary
   because regmap uses its own lock.

2. In MxL's LGM SoC, gate clocks can be controlled either from CGU clk driver
   i.e. this driver or directly from power management driver/daemon. It is
   dependent on the power policy/profile requirements of the end product.

   To support such use cases, provide option to override gate clks enable/disable
   by adding a flag GATE_CLK_HW which controls if these gate clks are controlled
   by HW i.e. this driver or overridden in order to allow it to be controlled
   by power profiles instead.

3. Fix a bug related to missing flags in one 'dcl' clk entry.

This patch series is based on below git tree (linux-v6.0-rc1):
git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git

v4:
- Address review concern (Stephen Boyd)
- Change the design of how GATE_CLKs are overridden.
  Make the clk provider return NULL when that clk needs
  to be overridden.

v3:
- Address review concern (Stephen Boyd)
- Change the method of fixing invalid width for reg read/write.

v2:
- Add option to override gate clks
- Fix a clk entry by adding relevant flags

v1:
- Initial version

Rahul Tanwar (4):
  clk: mxl: Switch from direct readl/writel based IO to regmap based IO
  clk: mxl: Remove redundant spinlocks
  clk: mxl: Add option to override gate clks
  clk: mxl: Fix a clk entry by adding relevant flags

 drivers/clk/x86/Kconfig       |   5 +-
 drivers/clk/x86/clk-cgu-pll.c |  23 ++------
 drivers/clk/x86/clk-cgu.c     | 105 ++++++++++------------------------
 drivers/clk/x86/clk-cgu.h     |  46 +++++++--------
 drivers/clk/x86/clk-lgm.c     |  18 +++---
 5 files changed, 72 insertions(+), 125 deletions(-)

-- 
2.17.1

[PATCH v4 1/4] clk: mxl: Switch from direct readl/writel based IO to regmap based IO

[Rahul Tanwar]

Earlier version of driver used direct io remapped register read
writes using readl/writel. But we need secure boot access which
is only possible when registers are read & written using regmap.
This is because the security bus/hook is written & coupled only
with regmap layer.

Switch the driver from direct readl/writel based register accesses
to regmap based register accesses.

Additionally, update the license headers to latest status.

Reviewed-by: Yi xin Zhu <yzhu@maxlinear.com>
Signed-off-by: Rahul Tanwar <rtanwar@maxlinear.com>
---
 drivers/clk/x86/Kconfig       |  5 +++--
 drivers/clk/x86/clk-cgu-pll.c | 10 +++++----
 drivers/clk/x86/clk-cgu.c     |  5 +++--
 drivers/clk/x86/clk-cgu.h     | 38 +++++++++++++++++++----------------
 drivers/clk/x86/clk-lgm.c     | 13 ++++++++----
 5 files changed, 42 insertions(+), 29 deletions(-)

diff --git a/drivers/clk/x86/Kconfig b/drivers/clk/x86/Kconfig
index 69642e15fcc1..ced99e082e3d 100644
--- a/drivers/clk/x86/Kconfig
+++ b/drivers/clk/x86/Kconfig
@@ -1,8 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0-only
 config CLK_LGM_CGU
 	depends on OF && HAS_IOMEM && (X86 || COMPILE_TEST)
+	select MFD_SYSCON
 	select OF_EARLY_FLATTREE
 	bool "Clock driver for Lightning Mountain(LGM) platform"
 	help
-	  Clock Generation Unit(CGU) driver for Intel Lightning Mountain(LGM)
-	  network processor SoC.
+	  Clock Generation Unit(CGU) driver for MaxLinear's x86 based
+	  Lightning Mountain(LGM) network processor SoC.
diff --git a/drivers/clk/x86/clk-cgu-pll.c b/drivers/clk/x86/clk-cgu-pll.c
index 3179557b5f78..c83083affe88 100644
--- a/drivers/clk/x86/clk-cgu-pll.c
+++ b/drivers/clk/x86/clk-cgu-pll.c
@@ -1,8 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
+ * Copyright (C) 2020-2022 MaxLinear, Inc.
  * Copyright (C) 2020 Intel Corporation.
- * Zhu YiXin <yixin.zhu@intel.com>
- * Rahul Tanwar <rahul.tanwar@intel.com>
+ * Zhu Yixin <yzhu@maxlinear.com>
+ * Rahul Tanwar <rtanwar@maxlinear.com>
  */
 
 #include <linux/clk-provider.h>
@@ -76,8 +77,9 @@ static int lgm_pll_enable(struct clk_hw *hw)
 
 	spin_lock_irqsave(&pll->lock, flags);
 	lgm_set_clk_val(pll->membase, pll->reg, 0, 1, 1);
-	ret = readl_poll_timeout_atomic(pll->membase + pll->reg,
-					val, (val & 0x1), 1, 100);
+	ret = regmap_read_poll_timeout_atomic(pll->membase, pll->reg,
+					      val, (val & 0x1), 1, 100);
+
 	spin_unlock_irqrestore(&pll->lock, flags);
 
 	return ret;
diff --git a/drivers/clk/x86/clk-cgu.c b/drivers/clk/x86/clk-cgu.c
index 33de600e0c38..f5f30a18f486 100644
--- a/drivers/clk/x86/clk-cgu.c
+++ b/drivers/clk/x86/clk-cgu.c
@@ -1,8 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
+ * Copyright (C) 2020-2022 MaxLinear, Inc.
  * Copyright (C) 2020 Intel Corporation.
- * Zhu YiXin <yixin.zhu@intel.com>
- * Rahul Tanwar <rahul.tanwar@intel.com>
+ * Zhu Yixin <yzhu@maxlinear.com>
+ * Rahul Tanwar <rtanwar@maxlinear.com>
  */
 #include <linux/clk-provider.h>
 #include <linux/device.h>
diff --git a/drivers/clk/x86/clk-cgu.h b/drivers/clk/x86/clk-cgu.h
index 4e22bfb22312..dbcb66468797 100644
--- a/drivers/clk/x86/clk-cgu.h
+++ b/drivers/clk/x86/clk-cgu.h
@@ -1,18 +1,19 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /*
- * Copyright(c) 2020 Intel Corporation.
- * Zhu YiXin <yixin.zhu@intel.com>
- * Rahul Tanwar <rahul.tanwar@intel.com>
+ * Copyright (C) 2020-2022 MaxLinear, Inc.
+ * Copyright (C) 2020 Intel Corporation.
+ * Zhu Yixin <yzhu@maxlinear.com>
+ * Rahul Tanwar <rtanwar@maxlinear.com>
  */
 
 #ifndef __CLK_CGU_H
 #define __CLK_CGU_H
 
-#include <linux/io.h>
+#include <linux/regmap.h>
 
 struct lgm_clk_mux {
 	struct clk_hw hw;
-	void __iomem *membase;
+	struct regmap *membase;
 	unsigned int reg;
 	u8 shift;
 	u8 width;
@@ -22,7 +23,7 @@ struct lgm_clk_mux {
 
 struct lgm_clk_divider {
 	struct clk_hw hw;
-	void __iomem *membase;
+	struct regmap *membase;
 	unsigned int reg;
 	u8 shift;
 	u8 width;
@@ -35,7 +36,7 @@ struct lgm_clk_divider {
 
 struct lgm_clk_ddiv {
 	struct clk_hw hw;
-	void __iomem *membase;
+	struct regmap *membase;
 	unsigned int reg;
 	u8 shift0;
 	u8 width0;
@@ -53,7 +54,7 @@ struct lgm_clk_ddiv {
 
 struct lgm_clk_gate {
 	struct clk_hw hw;
-	void __iomem *membase;
+	struct regmap *membase;
 	unsigned int reg;
 	u8 shift;
 	unsigned long flags;
@@ -77,7 +78,7 @@ enum lgm_clk_type {
  * @clk_data: array of hw clocks and clk number.
  */
 struct lgm_clk_provider {
-	void __iomem *membase;
+	struct regmap *membase;
 	struct device_node *np;
 	struct device *dev;
 	struct clk_hw_onecell_data clk_data;
@@ -92,7 +93,7 @@ enum pll_type {
 
 struct lgm_clk_pll {
 	struct clk_hw hw;
-	void __iomem *membase;
+	struct regmap *membase;
 	unsigned int reg;
 	unsigned long flags;
 	enum pll_type type;
@@ -300,29 +301,32 @@ struct lgm_clk_branch {
 		.div = _d,					\
 	}
 
-static inline void lgm_set_clk_val(void __iomem *membase, u32 reg,
+static inline void lgm_set_clk_val(struct regmap *membase, u32 reg,
 				   u8 shift, u8 width, u32 set_val)
 {
 	u32 mask = (GENMASK(width - 1, 0) << shift);
-	u32 regval;
 
-	regval = readl(membase + reg);
-	regval = (regval & ~mask) | ((set_val << shift) & mask);
-	writel(regval, membase + reg);
+	regmap_update_bits(membase, reg, mask, set_val << shift);
 }
 
-static inline u32 lgm_get_clk_val(void __iomem *membase, u32 reg,
+static inline u32 lgm_get_clk_val(struct regmap *membase, u32 reg,
 				  u8 shift, u8 width)
 {
 	u32 mask = (GENMASK(width - 1, 0) << shift);
 	u32 val;
 
-	val = readl(membase + reg);
+	if (regmap_read(membase, reg, &val)) {
+		WARN_ONCE(1, "Failed to read clk reg: 0x%x\n", reg);
+		return 0;
+	}
+
 	val = (val & mask) >> shift;
 
 	return val;
 }
 
+
+
 int lgm_clk_register_branches(struct lgm_clk_provider *ctx,
 			      const struct lgm_clk_branch *list,
 			      unsigned int nr_clk);
diff --git a/drivers/clk/x86/clk-lgm.c b/drivers/clk/x86/clk-lgm.c
index 020f4e83a5cc..4fa2bcaf71c8 100644
--- a/drivers/clk/x86/clk-lgm.c
+++ b/drivers/clk/x86/clk-lgm.c
@@ -1,10 +1,12 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
+ * Copyright (C) 2020-2022 MaxLinear, Inc.
  * Copyright (C) 2020 Intel Corporation.
- * Zhu YiXin <yixin.zhu@intel.com>
- * Rahul Tanwar <rahul.tanwar@intel.com>
+ * Zhu Yixin <yzhu@maxlinear.com>
+ * Rahul Tanwar <rtanwar@maxlinear.com>
  */
 #include <linux/clk-provider.h>
+#include <linux/mfd/syscon.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <dt-bindings/clock/intel,lgm-clk.h>
@@ -433,9 +435,12 @@ static int lgm_cgu_probe(struct platform_device *pdev)
 
 	ctx->clk_data.num = CLK_NR_CLKS;
 
-	ctx->membase = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(ctx->membase))
+	ctx->membase = syscon_node_to_regmap(np);
+	if (IS_ERR_OR_NULL(ctx->membase)) {
+		dev_err(dev, "Failed to get clk CGU iomem\n");
 		return PTR_ERR(ctx->membase);
+	}
+
 
 	ctx->np = np;
 	ctx->dev = dev;
-- 
2.17.1

Re: [PATCH v4 1/4] clk: mxl: Switch from direct readl/writel based IO to regmap based IO

[Stephen Boyd]

Quoting Rahul Tanwar (2022-10-12 23:48:30)
> Earlier version of driver used direct io remapped register read
> writes using readl/writel. But we need secure boot access which
> is only possible when registers are read & written using regmap.
> This is because the security bus/hook is written & coupled only
> with regmap layer.
> 
> Switch the driver from direct readl/writel based register accesses
> to regmap based register accesses.
> 
> Additionally, update the license headers to latest status.
> 
> Reviewed-by: Yi xin Zhu <yzhu@maxlinear.com>
> Signed-off-by: Rahul Tanwar <rtanwar@maxlinear.com>
> ---

Applied to clk-next

[PATCH v4 2/4] clk: mxl: Remove redundant spinlocks

[Rahul Tanwar]

Patch 1/4 of this patch series switches from direct readl/writel
based register access to regmap based register access. Instead
of using direct readl/writel, regmap API's are used to read, write
& read-modify-write clk registers. Regmap API's already use their
own spinlocks to serialize the register accesses across multiple
cores in which case additional driver spinlocks becomes redundant.

Hence, remove redundant spinlocks from driver in this patch 2/4.

Reviewed-by: Yi xin Zhu <yzhu@maxlinear.com>
Signed-off-by: Rahul Tanwar <rtanwar@maxlinear.com>
---
 drivers/clk/x86/clk-cgu-pll.c | 13 ------
 drivers/clk/x86/clk-cgu.c     | 80 ++++-------------------------------
 drivers/clk/x86/clk-cgu.h     |  6 ---
 drivers/clk/x86/clk-lgm.c     |  1 -
 4 files changed, 9 insertions(+), 91 deletions(-)

diff --git a/drivers/clk/x86/clk-cgu-pll.c b/drivers/clk/x86/clk-cgu-pll.c
index c83083affe88..409dbf55f4ca 100644
--- a/drivers/clk/x86/clk-cgu-pll.c
+++ b/drivers/clk/x86/clk-cgu-pll.c
@@ -41,13 +41,10 @@ static unsigned long lgm_pll_recalc_rate(struct clk_hw *hw, unsigned long prate)
 {
 	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
 	unsigned int div, mult, frac;
-	unsigned long flags;
 
-	spin_lock_irqsave(&pll->lock, flags);
 	mult = lgm_get_clk_val(pll->membase, PLL_REF_DIV(pll->reg), 0, 12);
 	div = lgm_get_clk_val(pll->membase, PLL_REF_DIV(pll->reg), 18, 6);
 	frac = lgm_get_clk_val(pll->membase, pll->reg, 2, 24);
-	spin_unlock_irqrestore(&pll->lock, flags);
 
 	if (pll->type == TYPE_LJPLL)
 		div *= 4;
@@ -58,12 +55,9 @@ static unsigned long lgm_pll_recalc_rate(struct clk_hw *hw, unsigned long prate)
 static int lgm_pll_is_enabled(struct clk_hw *hw)
 {
 	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
-	unsigned long flags;
 	unsigned int ret;
 
-	spin_lock_irqsave(&pll->lock, flags);
 	ret = lgm_get_clk_val(pll->membase, pll->reg, 0, 1);
-	spin_unlock_irqrestore(&pll->lock, flags);
 
 	return ret;
 }
@@ -71,16 +65,13 @@ static int lgm_pll_is_enabled(struct clk_hw *hw)
 static int lgm_pll_enable(struct clk_hw *hw)
 {
 	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
-	unsigned long flags;
 	u32 val;
 	int ret;
 
-	spin_lock_irqsave(&pll->lock, flags);
 	lgm_set_clk_val(pll->membase, pll->reg, 0, 1, 1);
 	ret = regmap_read_poll_timeout_atomic(pll->membase, pll->reg,
 					      val, (val & 0x1), 1, 100);
 
-	spin_unlock_irqrestore(&pll->lock, flags);
 
 	return ret;
 }
@@ -88,11 +79,8 @@ static int lgm_pll_enable(struct clk_hw *hw)
 static void lgm_pll_disable(struct clk_hw *hw)
 {
 	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
-	unsigned long flags;
 
-	spin_lock_irqsave(&pll->lock, flags);
 	lgm_set_clk_val(pll->membase, pll->reg, 0, 1, 0);
-	spin_unlock_irqrestore(&pll->lock, flags);
 }
 
 static const struct clk_ops lgm_pll_ops = {
@@ -123,7 +111,6 @@ lgm_clk_register_pll(struct lgm_clk_provider *ctx,
 		return ERR_PTR(-ENOMEM);
 
 	pll->membase = ctx->membase;
-	pll->lock = ctx->lock;
 	pll->reg = list->reg;
 	pll->flags = list->flags;
 	pll->type = list->type;
diff --git a/drivers/clk/x86/clk-cgu.c b/drivers/clk/x86/clk-cgu.c
index f5f30a18f486..1f7e93de67bc 100644
--- a/drivers/clk/x86/clk-cgu.c
+++ b/drivers/clk/x86/clk-cgu.c
@@ -25,14 +25,10 @@
 static struct clk_hw *lgm_clk_register_fixed(struct lgm_clk_provider *ctx,
 					     const struct lgm_clk_branch *list)
 {
-	unsigned long flags;
 
-	if (list->div_flags & CLOCK_FLAG_VAL_INIT) {
-		spin_lock_irqsave(&ctx->lock, flags);
+	if (list->div_flags & CLOCK_FLAG_VAL_INIT)
 		lgm_set_clk_val(ctx->membase, list->div_off, list->div_shift,
 				list->div_width, list->div_val);
-		spin_unlock_irqrestore(&ctx->lock, flags);
-	}
 
 	return clk_hw_register_fixed_rate(NULL, list->name,
 					  list->parent_data[0].name,
@@ -42,33 +38,27 @@ static struct clk_hw *lgm_clk_register_fixed(struct lgm_clk_provider *ctx,
 static u8 lgm_clk_mux_get_parent(struct clk_hw *hw)
 {
 	struct lgm_clk_mux *mux = to_lgm_clk_mux(hw);
-	unsigned long flags;
 	u32 val;
 
-	spin_lock_irqsave(&mux->lock, flags);
 	if (mux->flags & MUX_CLK_SW)
 		val = mux->reg;
 	else
 		val = lgm_get_clk_val(mux->membase, mux->reg, mux->shift,
 				      mux->width);
-	spin_unlock_irqrestore(&mux->lock, flags);
 	return clk_mux_val_to_index(hw, NULL, mux->flags, val);
 }
 
 static int lgm_clk_mux_set_parent(struct clk_hw *hw, u8 index)
 {
 	struct lgm_clk_mux *mux = to_lgm_clk_mux(hw);
-	unsigned long flags;
 	u32 val;
 
 	val = clk_mux_index_to_val(NULL, mux->flags, index);
-	spin_lock_irqsave(&mux->lock, flags);
 	if (mux->flags & MUX_CLK_SW)
 		mux->reg = val;
 	else
 		lgm_set_clk_val(mux->membase, mux->reg, mux->shift,
 				mux->width, val);
-	spin_unlock_irqrestore(&mux->lock, flags);
 
 	return 0;
 }
@@ -91,7 +81,7 @@ static struct clk_hw *
 lgm_clk_register_mux(struct lgm_clk_provider *ctx,
 		     const struct lgm_clk_branch *list)
 {
-	unsigned long flags, cflags = list->mux_flags;
+	unsigned long cflags = list->mux_flags;
 	struct device *dev = ctx->dev;
 	u8 shift = list->mux_shift;
 	u8 width = list->mux_width;
@@ -112,7 +102,6 @@ lgm_clk_register_mux(struct lgm_clk_provider *ctx,
 	init.num_parents = list->num_parents;
 
 	mux->membase = ctx->membase;
-	mux->lock = ctx->lock;
 	mux->reg = reg;
 	mux->shift = shift;
 	mux->width = width;
@@ -124,11 +113,8 @@ lgm_clk_register_mux(struct lgm_clk_provider *ctx,
 	if (ret)
 		return ERR_PTR(ret);
 
-	if (cflags & CLOCK_FLAG_VAL_INIT) {
-		spin_lock_irqsave(&mux->lock, flags);
+	if (cflags & CLOCK_FLAG_VAL_INIT)
 		lgm_set_clk_val(mux->membase, reg, shift, width, list->mux_val);
-		spin_unlock_irqrestore(&mux->lock, flags);
-	}
 
 	return hw;
 }
@@ -137,13 +123,10 @@ static unsigned long
 lgm_clk_divider_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
 {
 	struct lgm_clk_divider *divider = to_lgm_clk_divider(hw);
-	unsigned long flags;
 	unsigned int val;
 
-	spin_lock_irqsave(&divider->lock, flags);
 	val = lgm_get_clk_val(divider->membase, divider->reg,
 			      divider->shift, divider->width);
-	spin_unlock_irqrestore(&divider->lock, flags);
 
 	return divider_recalc_rate(hw, parent_rate, val, divider->table,
 				   divider->flags, divider->width);
@@ -164,7 +147,6 @@ lgm_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
 			 unsigned long prate)
 {
 	struct lgm_clk_divider *divider = to_lgm_clk_divider(hw);
-	unsigned long flags;
 	int value;
 
 	value = divider_get_val(rate, prate, divider->table,
@@ -172,10 +154,8 @@ lgm_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
 	if (value < 0)
 		return value;
 
-	spin_lock_irqsave(&divider->lock, flags);
 	lgm_set_clk_val(divider->membase, divider->reg,
 			divider->shift, divider->width, value);
-	spin_unlock_irqrestore(&divider->lock, flags);
 
 	return 0;
 }
@@ -183,12 +163,9 @@ lgm_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
 static int lgm_clk_divider_enable_disable(struct clk_hw *hw, int enable)
 {
 	struct lgm_clk_divider *div = to_lgm_clk_divider(hw);
-	unsigned long flags;
 
-	spin_lock_irqsave(&div->lock, flags);
 	lgm_set_clk_val(div->membase, div->reg, div->shift_gate,
 			div->width_gate, enable);
-	spin_unlock_irqrestore(&div->lock, flags);
 	return 0;
 }
 
@@ -214,7 +191,7 @@ static struct clk_hw *
 lgm_clk_register_divider(struct lgm_clk_provider *ctx,
 			 const struct lgm_clk_branch *list)
 {
-	unsigned long flags, cflags = list->div_flags;
+	unsigned long cflags = list->div_flags;
 	struct device *dev = ctx->dev;
 	struct lgm_clk_divider *div;
 	struct clk_init_data init = {};
@@ -237,7 +214,6 @@ lgm_clk_register_divider(struct lgm_clk_provider *ctx,
 	init.num_parents = 1;
 
 	div->membase = ctx->membase;
-	div->lock = ctx->lock;
 	div->reg = reg;
 	div->shift = shift;
 	div->width = width;
@@ -252,11 +228,8 @@ lgm_clk_register_divider(struct lgm_clk_provider *ctx,
 	if (ret)
 		return ERR_PTR(ret);
 
-	if (cflags & CLOCK_FLAG_VAL_INIT) {
-		spin_lock_irqsave(&div->lock, flags);
+	if (cflags & CLOCK_FLAG_VAL_INIT)
 		lgm_set_clk_val(div->membase, reg, shift, width, list->div_val);
-		spin_unlock_irqrestore(&div->lock, flags);
-	}
 
 	return hw;
 }
@@ -265,7 +238,6 @@ static struct clk_hw *
 lgm_clk_register_fixed_factor(struct lgm_clk_provider *ctx,
 			      const struct lgm_clk_branch *list)
 {
-	unsigned long flags;
 	struct clk_hw *hw;
 
 	hw = clk_hw_register_fixed_factor(ctx->dev, list->name,
@@ -274,12 +246,9 @@ lgm_clk_register_fixed_factor(struct lgm_clk_provider *ctx,
 	if (IS_ERR(hw))
 		return ERR_CAST(hw);
 
-	if (list->div_flags & CLOCK_FLAG_VAL_INIT) {
-		spin_lock_irqsave(&ctx->lock, flags);
+	if (list->div_flags & CLOCK_FLAG_VAL_INIT)
 		lgm_set_clk_val(ctx->membase, list->div_off, list->div_shift,
 				list->div_width, list->div_val);
-		spin_unlock_irqrestore(&ctx->lock, flags);
-	}
 
 	return hw;
 }
@@ -287,13 +256,10 @@ lgm_clk_register_fixed_factor(struct lgm_clk_provider *ctx,
 static int lgm_clk_gate_enable(struct clk_hw *hw)
 {
 	struct lgm_clk_gate *gate = to_lgm_clk_gate(hw);
-	unsigned long flags;
 	unsigned int reg;
 
-	spin_lock_irqsave(&gate->lock, flags);
 	reg = GATE_HW_REG_EN(gate->reg);
 	lgm_set_clk_val(gate->membase, reg, gate->shift, 1, 1);
-	spin_unlock_irqrestore(&gate->lock, flags);
 
 	return 0;
 }
@@ -301,25 +267,19 @@ static int lgm_clk_gate_enable(struct clk_hw *hw)
 static void lgm_clk_gate_disable(struct clk_hw *hw)
 {
 	struct lgm_clk_gate *gate = to_lgm_clk_gate(hw);
-	unsigned long flags;
 	unsigned int reg;
 
-	spin_lock_irqsave(&gate->lock, flags);
 	reg = GATE_HW_REG_DIS(gate->reg);
 	lgm_set_clk_val(gate->membase, reg, gate->shift, 1, 1);
-	spin_unlock_irqrestore(&gate->lock, flags);
 }
 
 static int lgm_clk_gate_is_enabled(struct clk_hw *hw)
 {
 	struct lgm_clk_gate *gate = to_lgm_clk_gate(hw);
 	unsigned int reg, ret;
-	unsigned long flags;
 
-	spin_lock_irqsave(&gate->lock, flags);
 	reg = GATE_HW_REG_STAT(gate->reg);
 	ret = lgm_get_clk_val(gate->membase, reg, gate->shift, 1);
-	spin_unlock_irqrestore(&gate->lock, flags);
 
 	return ret;
 }
@@ -334,7 +294,7 @@ static struct clk_hw *
 lgm_clk_register_gate(struct lgm_clk_provider *ctx,
 		      const struct lgm_clk_branch *list)
 {
-	unsigned long flags, cflags = list->gate_flags;
+	unsigned long cflags = list->gate_flags;
 	const char *pname = list->parent_data[0].name;
 	struct device *dev = ctx->dev;
 	u8 shift = list->gate_shift;
@@ -355,7 +315,6 @@ lgm_clk_register_gate(struct lgm_clk_provider *ctx,
 	init.num_parents = pname ? 1 : 0;
 
 	gate->membase = ctx->membase;
-	gate->lock = ctx->lock;
 	gate->reg = reg;
 	gate->shift = shift;
 	gate->flags = cflags;
@@ -367,9 +326,7 @@ lgm_clk_register_gate(struct lgm_clk_provider *ctx,
 		return ERR_PTR(ret);
 
 	if (cflags & CLOCK_FLAG_VAL_INIT) {
-		spin_lock_irqsave(&gate->lock, flags);
 		lgm_set_clk_val(gate->membase, reg, shift, 1, list->gate_val);
-		spin_unlock_irqrestore(&gate->lock, flags);
 	}
 
 	return hw;
@@ -444,24 +401,18 @@ lgm_clk_ddiv_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
 static int lgm_clk_ddiv_enable(struct clk_hw *hw)
 {
 	struct lgm_clk_ddiv *ddiv = to_lgm_clk_ddiv(hw);
-	unsigned long flags;
 
-	spin_lock_irqsave(&ddiv->lock, flags);
 	lgm_set_clk_val(ddiv->membase, ddiv->reg, ddiv->shift_gate,
 			ddiv->width_gate, 1);
-	spin_unlock_irqrestore(&ddiv->lock, flags);
 	return 0;
 }
 
 static void lgm_clk_ddiv_disable(struct clk_hw *hw)
 {
 	struct lgm_clk_ddiv *ddiv = to_lgm_clk_ddiv(hw);
-	unsigned long flags;
 
-	spin_lock_irqsave(&ddiv->lock, flags);
 	lgm_set_clk_val(ddiv->membase, ddiv->reg, ddiv->shift_gate,
 			ddiv->width_gate, 0);
-	spin_unlock_irqrestore(&ddiv->lock, flags);
 }
 
 static int
@@ -498,32 +449,25 @@ lgm_clk_ddiv_set_rate(struct clk_hw *hw, unsigned long rate,
 {
 	struct lgm_clk_ddiv *ddiv = to_lgm_clk_ddiv(hw);
 	u32 div, ddiv1, ddiv2;
-	unsigned long flags;
 
 	div = DIV_ROUND_CLOSEST_ULL((u64)prate, rate);
 
-	spin_lock_irqsave(&ddiv->lock, flags);
 	if (lgm_get_clk_val(ddiv->membase, ddiv->reg, ddiv->shift2, 1)) {
 		div = DIV_ROUND_CLOSEST_ULL((u64)div, 5);
 		div = div * 2;
 	}
 
-	if (div <= 0) {
-		spin_unlock_irqrestore(&ddiv->lock, flags);
+	if (div <= 0)
 		return -EINVAL;
-	}
 
-	if (lgm_clk_get_ddiv_val(div, &ddiv1, &ddiv2)) {
-		spin_unlock_irqrestore(&ddiv->lock, flags);
+	if (lgm_clk_get_ddiv_val(div, &ddiv1, &ddiv2))
 		return -EINVAL;
-	}
 
 	lgm_set_clk_val(ddiv->membase, ddiv->reg, ddiv->shift0, ddiv->width0,
 			ddiv1 - 1);
 
 	lgm_set_clk_val(ddiv->membase, ddiv->reg,  ddiv->shift1, ddiv->width1,
 			ddiv2 - 1);
-	spin_unlock_irqrestore(&ddiv->lock, flags);
 
 	return 0;
 }
@@ -534,18 +478,15 @@ lgm_clk_ddiv_round_rate(struct clk_hw *hw, unsigned long rate,
 {
 	struct lgm_clk_ddiv *ddiv = to_lgm_clk_ddiv(hw);
 	u32 div, ddiv1, ddiv2;
-	unsigned long flags;
 	u64 rate64;
 
 	div = DIV_ROUND_CLOSEST_ULL((u64)*prate, rate);
 
 	/* if predivide bit is enabled, modify div by factor of 2.5 */
-	spin_lock_irqsave(&ddiv->lock, flags);
 	if (lgm_get_clk_val(ddiv->membase, ddiv->reg, ddiv->shift2, 1)) {
 		div = div * 2;
 		div = DIV_ROUND_CLOSEST_ULL((u64)div, 5);
 	}
-	spin_unlock_irqrestore(&ddiv->lock, flags);
 
 	if (div <= 0)
 		return *prate;
@@ -559,12 +500,10 @@ lgm_clk_ddiv_round_rate(struct clk_hw *hw, unsigned long rate,
 	do_div(rate64, ddiv2);
 
 	/* if predivide bit is enabled, modify rounded rate by factor of 2.5 */
-	spin_lock_irqsave(&ddiv->lock, flags);
 	if (lgm_get_clk_val(ddiv->membase, ddiv->reg, ddiv->shift2, 1)) {
 		rate64 = rate64 * 2;
 		rate64 = DIV_ROUND_CLOSEST_ULL(rate64, 5);
 	}
-	spin_unlock_irqrestore(&ddiv->lock, flags);
 
 	return rate64;
 }
@@ -601,7 +540,6 @@ int lgm_clk_register_ddiv(struct lgm_clk_provider *ctx,
 		init.num_parents = 1;
 
 		ddiv->membase = ctx->membase;
-		ddiv->lock = ctx->lock;
 		ddiv->reg = list->reg;
 		ddiv->shift0 = list->shift0;
 		ddiv->width0 = list->width0;
diff --git a/drivers/clk/x86/clk-cgu.h b/drivers/clk/x86/clk-cgu.h
index dbcb66468797..0aa0f35d63a0 100644
--- a/drivers/clk/x86/clk-cgu.h
+++ b/drivers/clk/x86/clk-cgu.h
@@ -18,7 +18,6 @@ struct lgm_clk_mux {
 	u8 shift;
 	u8 width;
 	unsigned long flags;
-	spinlock_t lock;
 };
 
 struct lgm_clk_divider {
@@ -31,7 +30,6 @@ struct lgm_clk_divider {
 	u8 width_gate;
 	unsigned long flags;
 	const struct clk_div_table *table;
-	spinlock_t lock;
 };
 
 struct lgm_clk_ddiv {
@@ -49,7 +47,6 @@ struct lgm_clk_ddiv {
 	unsigned int mult;
 	unsigned int div;
 	unsigned long flags;
-	spinlock_t lock;
 };
 
 struct lgm_clk_gate {
@@ -58,7 +55,6 @@ struct lgm_clk_gate {
 	unsigned int reg;
 	u8 shift;
 	unsigned long flags;
-	spinlock_t lock;
 };
 
 enum lgm_clk_type {
@@ -82,7 +78,6 @@ struct lgm_clk_provider {
 	struct device_node *np;
 	struct device *dev;
 	struct clk_hw_onecell_data clk_data;
-	spinlock_t lock;
 };
 
 enum pll_type {
@@ -97,7 +92,6 @@ struct lgm_clk_pll {
 	unsigned int reg;
 	unsigned long flags;
 	enum pll_type type;
-	spinlock_t lock;
 };
 
 /**
diff --git a/drivers/clk/x86/clk-lgm.c b/drivers/clk/x86/clk-lgm.c
index 4fa2bcaf71c8..e312af42e97a 100644
--- a/drivers/clk/x86/clk-lgm.c
+++ b/drivers/clk/x86/clk-lgm.c
@@ -444,7 +444,6 @@ static int lgm_cgu_probe(struct platform_device *pdev)
 
 	ctx->np = np;
 	ctx->dev = dev;
-	spin_lock_init(&ctx->lock);
 
 	ret = lgm_clk_register_plls(ctx, lgm_pll_clks,
 				    ARRAY_SIZE(lgm_pll_clks));
-- 
2.17.1

Re: [PATCH v4 2/4] clk: mxl: Remove redundant spinlocks

[Stephen Boyd]

Quoting Rahul Tanwar (2022-10-12 23:48:31)
> Patch 1/4 of this patch series switches from direct readl/writel
> based register access to regmap based register access. Instead
> of using direct readl/writel, regmap API's are used to read, write
> & read-modify-write clk registers. Regmap API's already use their
> own spinlocks to serialize the register accesses across multiple
> cores in which case additional driver spinlocks becomes redundant.
> 
> Hence, remove redundant spinlocks from driver in this patch 2/4.
> 
> Reviewed-by: Yi xin Zhu <yzhu@maxlinear.com>
> Signed-off-by: Rahul Tanwar <rtanwar@maxlinear.com>
> ---

Applied to clk-next

[PATCH v4 3/4] clk: mxl: Add option to override gate clks

[Rahul Tanwar]

In MxL's LGM SoC, gate clocks can be controlled either from CGU clk driver
i.e. this driver or directly from power management driver/daemon. It is
dependent on the power policy/profile requirements of the end product.

To support such use cases, provide option to override gate clks enable/disable
by adding a flag GATE_CLK_HW which controls if these gate clks are controlled
by HW i.e. this driver or overridden in order to allow it to be controlled
by power profiles instead.

Reviewed-by: Yi xin Zhu <yzhu@maxlinear.com>
Signed-off-by: Rahul Tanwar <rtanwar@maxlinear.com>
---
 drivers/clk/x86/clk-cgu.c | 15 ++++++++++++++-
 drivers/clk/x86/clk-cgu.h |  1 +
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/x86/clk-cgu.c b/drivers/clk/x86/clk-cgu.c
index 1f7e93de67bc..5eafd7e0d945 100644
--- a/drivers/clk/x86/clk-cgu.c
+++ b/drivers/clk/x86/clk-cgu.c
@@ -354,8 +354,21 @@ int lgm_clk_register_branches(struct lgm_clk_provider *ctx,
 			hw = lgm_clk_register_fixed_factor(ctx, list);
 			break;
 		case CLK_TYPE_GATE:
-			hw = lgm_clk_register_gate(ctx, list);
+			if (list->gate_flags & GATE_CLK_HW)
+				hw = lgm_clk_register_gate(ctx, list);
+			else
+				/*
+				 * GATE_CLKs can be controlled either from
+				 * CGU clk driver i.e. this driver or directly
+				 * from power management driver/daemon. It is
+				 * dependent on the power policy/profile requirements
+				 * of the end product. To override control of gate
+				 * clks from this driver, provide NULL for this index
+				 * of gate clk provider.
+				 */
+				hw = NULL;
 			break;
+
 		default:
 			dev_err(ctx->dev, "invalid clk type\n");
 			return -EINVAL;
diff --git a/drivers/clk/x86/clk-cgu.h b/drivers/clk/x86/clk-cgu.h
index 0aa0f35d63a0..73ce84345f81 100644
--- a/drivers/clk/x86/clk-cgu.h
+++ b/drivers/clk/x86/clk-cgu.h
@@ -197,6 +197,7 @@ struct lgm_clk_branch {
 /* clock flags definition */
 #define CLOCK_FLAG_VAL_INIT	BIT(16)
 #define MUX_CLK_SW		BIT(17)
+#define GATE_CLK_HW		BIT(18)
 
 #define LGM_MUX(_id, _name, _pdata, _f, _reg,		\
 		_shift, _width, _cf, _v)		\
-- 
2.17.1

Re: [PATCH v4 3/4] clk: mxl: Add option to override gate clks

[Stephen Boyd]

Quoting Rahul Tanwar (2022-10-12 23:48:32)
> In MxL's LGM SoC, gate clocks can be controlled either from CGU clk driver
> i.e. this driver or directly from power management driver/daemon. It is
> dependent on the power policy/profile requirements of the end product.
> 
> To support such use cases, provide option to override gate clks enable/disable
> by adding a flag GATE_CLK_HW which controls if these gate clks are controlled
> by HW i.e. this driver or overridden in order to allow it to be controlled
> by power profiles instead.
> 
> Reviewed-by: Yi xin Zhu <yzhu@maxlinear.com>
> Signed-off-by: Rahul Tanwar <rtanwar@maxlinear.com>
> ---

Applied to clk-next

[PATCH v4 4/4] clk: mxl: Fix a clk entry by adding relevant flags

[Rahul Tanwar]

One of the clock entry "dcl" clk has some HW limitations. One is that
its rate can only by changed by changing its parent clk's rate & two
is that HW does not support enable/disable for this clk.

Handle above two limitations by adding relevant flags. Add standard
flag CLK_SET_RATE_PARENT to handle rate change and add driver internal
flag DIV_CLK_NO_MASK to handle enable/disable.

Fixes: d058fd9e8984c ("clk: intel: Add CGU clock driver for a new SoC")
Reviewed-by: Yi xin Zhu <yzhu@maxlinear.com>
Signed-off-by: Rahul Tanwar <rtanwar@maxlinear.com>
---
 drivers/clk/x86/clk-cgu.c | 5 +++--
 drivers/clk/x86/clk-cgu.h | 1 +
 drivers/clk/x86/clk-lgm.c | 4 ++--
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/x86/clk-cgu.c b/drivers/clk/x86/clk-cgu.c
index 5eafd7e0d945..ce253cce5814 100644
--- a/drivers/clk/x86/clk-cgu.c
+++ b/drivers/clk/x86/clk-cgu.c
@@ -164,8 +164,9 @@ static int lgm_clk_divider_enable_disable(struct clk_hw *hw, int enable)
 {
 	struct lgm_clk_divider *div = to_lgm_clk_divider(hw);
 
-	lgm_set_clk_val(div->membase, div->reg, div->shift_gate,
-			div->width_gate, enable);
+	if (div->flags != DIV_CLK_NO_MASK)
+		lgm_set_clk_val(div->membase, div->reg, div->shift_gate,
+				div->width_gate, enable);
 	return 0;
 }
 
diff --git a/drivers/clk/x86/clk-cgu.h b/drivers/clk/x86/clk-cgu.h
index 73ce84345f81..bcaf8aec94e5 100644
--- a/drivers/clk/x86/clk-cgu.h
+++ b/drivers/clk/x86/clk-cgu.h
@@ -198,6 +198,7 @@ struct lgm_clk_branch {
 #define CLOCK_FLAG_VAL_INIT	BIT(16)
 #define MUX_CLK_SW		BIT(17)
 #define GATE_CLK_HW		BIT(18)
+#define DIV_CLK_NO_MASK		BIT(19)
 
 #define LGM_MUX(_id, _name, _pdata, _f, _reg,		\
 		_shift, _width, _cf, _v)		\
diff --git a/drivers/clk/x86/clk-lgm.c b/drivers/clk/x86/clk-lgm.c
index e312af42e97a..4de77b2c750d 100644
--- a/drivers/clk/x86/clk-lgm.c
+++ b/drivers/clk/x86/clk-lgm.c
@@ -255,8 +255,8 @@ static const struct lgm_clk_branch lgm_branch_clks[] = {
 	LGM_FIXED(LGM_CLK_SLIC, "slic", NULL, 0, CGU_IF_CLK1,
 		  8, 2, CLOCK_FLAG_VAL_INIT, 8192000, 2),
 	LGM_FIXED(LGM_CLK_DOCSIS, "v_docsis", NULL, 0, 0, 0, 0, 0, 16000000, 0),
-	LGM_DIV(LGM_CLK_DCL, "dcl", "v_ifclk", 0, CGU_PCMCR,
-		25, 3, 0, 0, 0, 0, dcl_div),
+	LGM_DIV(LGM_CLK_DCL, "dcl", "v_ifclk", CLK_SET_RATE_PARENT, CGU_PCMCR,
+		25, 3, 0, 0, DIV_CLK_NO_MASK, 0, dcl_div),
 	LGM_MUX(LGM_CLK_PCM, "pcm", pcm_p, 0, CGU_C55_PCMCR,
 		0, 1, CLK_MUX_ROUND_CLOSEST, 0),
 	LGM_FIXED_FACTOR(LGM_CLK_DDR_PHY, "ddr_phy", "ddr",
-- 
2.17.1

Re: [PATCH v4 4/4] clk: mxl: Fix a clk entry by adding relevant flags

[Stephen Boyd]

Quoting Rahul Tanwar (2022-10-12 23:48:33)
> One of the clock entry "dcl" clk has some HW limitations. One is that
> its rate can only by changed by changing its parent clk's rate & two
> is that HW does not support enable/disable for this clk.
> 
> Handle above two limitations by adding relevant flags. Add standard
> flag CLK_SET_RATE_PARENT to handle rate change and add driver internal
> flag DIV_CLK_NO_MASK to handle enable/disable.
> 
> Fixes: d058fd9e8984c ("clk: intel: Add CGU clock driver for a new SoC")
> Reviewed-by: Yi xin Zhu <yzhu@maxlinear.com>
> Signed-off-by: Rahul Tanwar <rtanwar@maxlinear.com>
> ---

Applied to clk-next