1 files changed, 149 insertions, 32 deletions

diff --git a/drivers/clk/renesas/renesas-cpg-mssr.c b/drivers/clk/renesas/renesas-cpg-mssr.c
index de1cf7ba45b7..7f9b7aa39790 100644
--- a/drivers/clk/renesas/renesas-cpg-mssr.c
+++ b/drivers/clk/renesas/renesas-cpg-mssr.c
@@ -40,8 +40,10 @@
 #define WARN_DEBUG(x)	do { } while (0)
 #endif
 
+#define RZT2H_RESET_REG_READ_COUNT	7
+
 /*
- * Module Standby and Software Reset register offets.
+ * Module Standby and Software Reset register offsets.
  *
  * If the registers exist, these are valid for SH-Mobile, R-Mobile,
  * R-Car Gen2, R-Car Gen3, and RZ/G1.
@@ -137,6 +139,22 @@ static const u16 srcr_for_gen4[] = {
 	0x2C60, 0x2C64, 0x2C68, 0x2C6C, 0x2C70, 0x2C74,
 };
 
+static const u16 mrcr_for_rzt2h[] = {
+	0x240,	/* MRCTLA */
+	0x244,	/* Reserved */
+	0x248,	/* Reserved */
+	0x24C,	/* Reserved */
+	0x250,	/* MRCTLE */
+	0x254,	/* Reserved */
+	0x258,	/* Reserved */
+	0x25C,	/* Reserved */
+	0x260,	/* MRCTLI */
+	0x264,	/* Reserved */
+	0x268,	/* Reserved */
+	0x26C,	/* Reserved */
+	0x270,	/* MRCTLM */
+};
+
 /*
  * Software Reset Clearing Register offsets
  */
@@ -290,9 +308,20 @@ static int cpg_mstp_clock_endisable(struct clk_hw *hw, bool enable)
 
 	spin_unlock_irqrestore(&priv->pub.rmw_lock, flags);
 
-	if (!enable || priv->reg_layout == CLK_REG_LAYOUT_RZ_A ||
-	    priv->reg_layout == CLK_REG_LAYOUT_RZ_T2H)
+	if (!enable || priv->reg_layout == CLK_REG_LAYOUT_RZ_A)
+		return 0;
+
+	if (priv->reg_layout == CLK_REG_LAYOUT_RZ_T2H) {
+		/*
+		 * For the RZ/T2H case, it is necessary to perform a read-back after
+		 * accessing the MSTPCRm register and to dummy-read any register of
+		 * the IP at least seven times. Instead of memory-mapping the IP
+		 * register, we simply add a delay after the read operation.
+		 */
+		cpg_rzt2h_mstp_read(hw, priv->control_regs[reg]);
+		udelay(10);
 		return 0;
+	}
 
 	error = readl_poll_timeout_atomic(priv->pub.base0 + priv->status_regs[reg],
 					  value, !(value & bitmask), 0, 10);
@@ -451,7 +480,7 @@ static void __init cpg_mssr_register_core_clk(const struct cpg_core_clk *core,
 		break;
 	}
 
-	if (IS_ERR_OR_NULL(clk))
+	if (IS_ERR(clk))
 		goto fail;
 
 	dev_dbg(dev, "Core clock %pC at %lu Hz\n", clk, clk_get_rate(clk));
@@ -676,64 +705,133 @@ static int __init cpg_mssr_add_clk_domain(struct device *dev,
 
 #define rcdev_to_priv(x)	container_of(x, struct cpg_mssr_priv, rcdev)
 
-static int cpg_mssr_reset(struct reset_controller_dev *rcdev,
-			  unsigned long id)
+static int cpg_mssr_reset_operate(struct reset_controller_dev *rcdev,
+				  const char *func, bool set, unsigned long id)
 {
 	struct cpg_mssr_priv *priv = rcdev_to_priv(rcdev);
 	unsigned int reg = id / 32;
 	unsigned int bit = id % 32;
+	const u16 off = set ? priv->reset_regs[reg] : priv->reset_clear_regs[reg];
 	u32 bitmask = BIT(bit);
 
-	dev_dbg(priv->dev, "reset %u%02u\n", reg, bit);
+	if (func)
+		dev_dbg(priv->dev, "%s %u%02u\n", func, reg, bit);
+
+	writel(bitmask, priv->pub.base0 + off);
+	readl(priv->pub.base0 + off);
+	barrier_data(priv->pub.base0 + off);
+
+	return 0;
+}
+
+static int cpg_mssr_reset(struct reset_controller_dev *rcdev,
+			  unsigned long id)
+{
+	struct cpg_mssr_priv *priv = rcdev_to_priv(rcdev);
 
 	/* Reset module */
-	writel(bitmask, priv->pub.base0 + priv->reset_regs[reg]);
+	cpg_mssr_reset_operate(rcdev, "reset", true, id);
 
-	/* Wait for at least one cycle of the RCLK clock (@ ca. 32 kHz) */
-	udelay(35);
+	/*
+	 * On R-Car Gen4, delay after SRCR has been written is 1ms.
+	 * On older SoCs, delay after SRCR has been written is 35us
+	 * (one cycle of the RCLK clock @ ca. 32 kHz).
+	 */
+	if (priv->reg_layout == CLK_REG_LAYOUT_RCAR_GEN4)
+		usleep_range(1000, 2000);
+	else
+		usleep_range(35, 1000);
 
 	/* Release module from reset state */
-	writel(bitmask, priv->pub.base0 + priv->reset_clear_regs[reg]);
-
-	return 0;
+	return cpg_mssr_reset_operate(rcdev, NULL, false, id);
 }
 
 static int cpg_mssr_assert(struct reset_controller_dev *rcdev, unsigned long id)
 {
+	return cpg_mssr_reset_operate(rcdev, "assert", true, id);
+}
+
+static int cpg_mssr_deassert(struct reset_controller_dev *rcdev,
+			     unsigned long id)
+{
+	return cpg_mssr_reset_operate(rcdev, "deassert", false, id);
+}
+
+static int cpg_mssr_status(struct reset_controller_dev *rcdev,
+			   unsigned long id)
+{
 	struct cpg_mssr_priv *priv = rcdev_to_priv(rcdev);
 	unsigned int reg = id / 32;
 	unsigned int bit = id % 32;
 	u32 bitmask = BIT(bit);
 
-	dev_dbg(priv->dev, "assert %u%02u\n", reg, bit);
-
-	writel(bitmask, priv->pub.base0 + priv->reset_regs[reg]);
-	return 0;
+	return !!(readl(priv->pub.base0 + priv->reset_regs[reg]) & bitmask);
 }
 
-static int cpg_mssr_deassert(struct reset_controller_dev *rcdev,
-			     unsigned long id)
+static int cpg_mrcr_set_reset_state(struct reset_controller_dev *rcdev,
+				    unsigned long id, bool set)
 {
 	struct cpg_mssr_priv *priv = rcdev_to_priv(rcdev);
 	unsigned int reg = id / 32;
 	unsigned int bit = id % 32;
 	u32 bitmask = BIT(bit);
+	void __iomem *reg_addr;
+	unsigned long flags;
+	unsigned int i;
+	u32 val;
+
+	dev_dbg(priv->dev, "%s %u%02u\n", set ? "assert" : "deassert", reg, bit);
+
+	spin_lock_irqsave(&priv->pub.rmw_lock, flags);
+
+	reg_addr = priv->pub.base0 + priv->reset_regs[reg];
+	/* Read current value and modify */
+	val = readl(reg_addr);
+	if (set)
+		val |= bitmask;
+	else
+		val &= ~bitmask;
+	writel(val, reg_addr);
 
-	dev_dbg(priv->dev, "deassert %u%02u\n", reg, bit);
+	/*
+	 * For secure processing after release from a module reset, one must
+	 * perform multiple dummy reads of the same register.
+	 */
+	for (i = 0; !set && i < RZT2H_RESET_REG_READ_COUNT; i++)
+		readl(reg_addr);
+
+	/* Verify the operation */
+	val = readl(reg_addr);
+	if (set == !(bitmask & val)) {
+		dev_err(priv->dev, "Reset register %u%02u operation failed\n", reg, bit);
+		spin_unlock_irqrestore(&priv->pub.rmw_lock, flags);
+		return -EIO;
+	}
+
+	spin_unlock_irqrestore(&priv->pub.rmw_lock, flags);
 
-	writel(bitmask, priv->pub.base0 + priv->reset_clear_regs[reg]);
 	return 0;
 }
 
-static int cpg_mssr_status(struct reset_controller_dev *rcdev,
-			   unsigned long id)
+static int cpg_mrcr_reset(struct reset_controller_dev *rcdev, unsigned long id)
 {
-	struct cpg_mssr_priv *priv = rcdev_to_priv(rcdev);
-	unsigned int reg = id / 32;
-	unsigned int bit = id % 32;
-	u32 bitmask = BIT(bit);
+	int ret;
 
-	return !!(readl(priv->pub.base0 + priv->reset_regs[reg]) & bitmask);
+	ret = cpg_mrcr_set_reset_state(rcdev, id, true);
+	if (ret)
+		return ret;
+
+	return cpg_mrcr_set_reset_state(rcdev, id, false);
+}
+
+static int cpg_mrcr_assert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	return cpg_mrcr_set_reset_state(rcdev, id, true);
+}
+
+static int cpg_mrcr_deassert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	return cpg_mrcr_set_reset_state(rcdev, id, false);
 }
 
 static const struct reset_control_ops cpg_mssr_reset_ops = {
@@ -743,6 +841,13 @@ static const struct reset_control_ops cpg_mssr_reset_ops = {
 	.status = cpg_mssr_status,
 };
 
+static const struct reset_control_ops cpg_mrcr_reset_ops = {
+	.reset = cpg_mrcr_reset,
+	.assert = cpg_mrcr_assert,
+	.deassert = cpg_mrcr_deassert,
+	.status = cpg_mssr_status,
+};
+
 static int cpg_mssr_reset_xlate(struct reset_controller_dev *rcdev,
 				const struct of_phandle_args *reset_spec)
 {
@@ -760,11 +865,23 @@ static int cpg_mssr_reset_xlate(struct reset_controller_dev *rcdev,
 
 static int cpg_mssr_reset_controller_register(struct cpg_mssr_priv *priv)
 {
-	priv->rcdev.ops = &cpg_mssr_reset_ops;
+	/*
+	 * RZ/T2H (and family) has the Module Reset Control Registers
+	 * which allows control resets of certain modules.
+	 * The number of resets is not equal to the number of module clocks.
+	 */
+	if (priv->reg_layout == CLK_REG_LAYOUT_RZ_T2H) {
+		priv->rcdev.ops = &cpg_mrcr_reset_ops;
+		priv->rcdev.nr_resets = ARRAY_SIZE(mrcr_for_rzt2h) * 32;
+	} else {
+		priv->rcdev.ops = &cpg_mssr_reset_ops;
+		priv->rcdev.nr_resets = priv->num_mod_clks;
+	}
+
 	priv->rcdev.of_node = priv->dev->of_node;
 	priv->rcdev.of_reset_n_cells = 1;
 	priv->rcdev.of_xlate = cpg_mssr_reset_xlate;
-	priv->rcdev.nr_resets = priv->num_mod_clks;
+
 	return devm_reset_controller_register(priv->dev, &priv->rcdev);
 }
 
@@ -1169,6 +1286,7 @@ static int __init cpg_mssr_common_init(struct device *dev,
 		priv->control_regs = stbcr;
 	} else if (priv->reg_layout == CLK_REG_LAYOUT_RZ_T2H) {
 		priv->control_regs = mstpcr_for_rzt2h;
+		priv->reset_regs = mrcr_for_rzt2h;
 	} else if (priv->reg_layout == CLK_REG_LAYOUT_RCAR_GEN4) {
 		priv->status_regs = mstpsr_for_gen4;
 		priv->control_regs = mstpcr_for_gen4;
@@ -1265,8 +1383,7 @@ static int __init cpg_mssr_probe(struct platform_device *pdev)
 		goto reserve_exit;
 
 	/* Reset Controller not supported for Standby Control SoCs */
-	if (priv->reg_layout == CLK_REG_LAYOUT_RZ_A ||
-	    priv->reg_layout == CLK_REG_LAYOUT_RZ_T2H)
+	if (priv->reg_layout == CLK_REG_LAYOUT_RZ_A)
 		goto reserve_exit;
 
 	error = cpg_mssr_reset_controller_register(priv);