6 files changed, 244 insertions, 13 deletions

diff --git a/arch/arm/mach-ux500/Kconfig b/arch/arm/mach-ux500/Kconfig
index c1086ebe0050..24ed7f4a87a4 100644
--- a/arch/arm/mach-ux500/Kconfig
+++ b/arch/arm/mach-ux500/Kconfig
@@ -29,6 +29,7 @@ menuconfig ARCH_U8500
 	select REGULATOR_DB8500_PRCMU
 	select REGULATOR_FIXED_VOLTAGE
 	select SOC_BUS
+	select RESET_CONTROLLER
 	help
 	  Support for ST-Ericsson's Ux500 architecture
 
diff --git a/drivers/clk/ux500/Makefile b/drivers/clk/ux500/Makefile
index 53fd29002401..c29b83df403e 100644
--- a/drivers/clk/ux500/Makefile
+++ b/drivers/clk/ux500/Makefile
@@ -8,6 +8,9 @@ obj-y += clk-prcc.o
 obj-y += clk-prcmu.o
 obj-y += clk-sysctrl.o
 
+# Reset control
+obj-y += reset-prcc.o
+
 # Clock definitions
 obj-y += u8500_of_clk.o
 
diff --git a/drivers/clk/ux500/prcc.h b/drivers/clk/ux500/prcc.h
new file mode 100644
index 000000000000..5b6774d79506
--- /dev/null
+++ b/drivers/clk/ux500/prcc.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __PRCC_H
+#define __PRCC_H
+
+#define PRCC_NUM_PERIPH_CLUSTERS 6
+#define PRCC_PERIPHS_PER_CLUSTER 32
+
+/* CLKRST4 is missing making it hard to index things */
+enum clkrst_index {
+	CLKRST1_INDEX = 0,
+	CLKRST2_INDEX,
+	CLKRST3_INDEX,
+	CLKRST5_INDEX,
+	CLKRST6_INDEX,
+	CLKRST_MAX,
+};
+
+#endif
diff --git a/drivers/clk/ux500/reset-prcc.c b/drivers/clk/ux500/reset-prcc.c
new file mode 100644
index 000000000000..fcd5d042806a
--- /dev/null
+++ b/drivers/clk/ux500/reset-prcc.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Reset controller portions for the U8500 PRCC
+ * Copyright (C) 2021 Linus Walleij <linus.walleij@linaro.org>
+ */
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/types.h>
+#include <linux/reset-controller.h>
+#include <linux/bits.h>
+#include <linux/delay.h>
+
+#include "prcc.h"
+#include "reset-prcc.h"
+
+#define to_u8500_prcc_reset(p) container_of((p), struct u8500_prcc_reset, rcdev)
+
+/* This macro flattens the 2-dimensional PRCC numberspace */
+#define PRCC_RESET_LINE(prcc_num, bit) \
+	(((prcc_num) * PRCC_PERIPHS_PER_CLUSTER) + (bit))
+
+/*
+ * Reset registers in each PRCC - the reset lines are active low
+ * so what you need to do is write a bit for the peripheral you
+ * want to put into reset into the CLEAR register, this will assert
+ * the reset by pulling the line low. SET take the device out of
+ * reset. The status reflects the actual state of the line.
+ */
+#define PRCC_K_SOFTRST_SET		0x018
+#define PRCC_K_SOFTRST_CLEAR		0x01c
+#define PRCC_K_RST_STATUS		0x020
+
+static int prcc_num_to_index(unsigned int num)
+{
+	switch (num) {
+	case 1:
+		return CLKRST1_INDEX;
+	case 2:
+		return CLKRST2_INDEX;
+	case 3:
+		return CLKRST3_INDEX;
+	case 5:
+		return CLKRST5_INDEX;
+	case 6:
+		return CLKRST6_INDEX;
+	}
+	return -EINVAL;
+}
+
+static void __iomem *u8500_prcc_reset_base(struct u8500_prcc_reset *ur,
+					   unsigned long id)
+{
+	unsigned int prcc_num, index;
+
+	prcc_num = id / PRCC_PERIPHS_PER_CLUSTER;
+	index = prcc_num_to_index(prcc_num);
+
+	if (index > ARRAY_SIZE(ur->base))
+		return NULL;
+
+	return ur->base[index];
+}
+
+static int u8500_prcc_reset(struct reset_controller_dev *rcdev,
+			    unsigned long id)
+{
+	struct u8500_prcc_reset *ur = to_u8500_prcc_reset(rcdev);
+	void __iomem *base = u8500_prcc_reset_base(ur, id);
+	unsigned int bit = id % PRCC_PERIPHS_PER_CLUSTER;
+
+	pr_debug("PRCC cycle reset id %lu, bit %u\n", id, bit);
+
+	/*
+	 * Assert reset and then release it. The one microsecond
+	 * delay is found in the vendor reference code.
+	 */
+	writel(BIT(bit), base + PRCC_K_SOFTRST_CLEAR);
+	udelay(1);
+	writel(BIT(bit), base + PRCC_K_SOFTRST_SET);
+	udelay(1);
+
+	return 0;
+}
+
+static int u8500_prcc_reset_assert(struct reset_controller_dev *rcdev,
+				   unsigned long id)
+{
+	struct u8500_prcc_reset *ur = to_u8500_prcc_reset(rcdev);
+	void __iomem *base = u8500_prcc_reset_base(ur, id);
+	unsigned int bit = id % PRCC_PERIPHS_PER_CLUSTER;
+
+	pr_debug("PRCC assert reset id %lu, bit %u\n", id, bit);
+	writel(BIT(bit), base + PRCC_K_SOFTRST_CLEAR);
+
+	return 0;
+}
+
+static int u8500_prcc_reset_deassert(struct reset_controller_dev *rcdev,
+				     unsigned long id)
+{
+	struct u8500_prcc_reset *ur = to_u8500_prcc_reset(rcdev);
+	void __iomem *base = u8500_prcc_reset_base(ur, id);
+	unsigned int bit = id % PRCC_PERIPHS_PER_CLUSTER;
+
+	pr_debug("PRCC deassert reset id %lu, bit %u\n", id, bit);
+	writel(BIT(bit), base + PRCC_K_SOFTRST_SET);
+
+	return 0;
+}
+
+static int u8500_prcc_reset_status(struct reset_controller_dev *rcdev,
+				   unsigned long id)
+{
+	struct u8500_prcc_reset *ur = to_u8500_prcc_reset(rcdev);
+	void __iomem *base = u8500_prcc_reset_base(ur, id);
+	unsigned int bit = id % PRCC_PERIPHS_PER_CLUSTER;
+	u32 val;
+
+	pr_debug("PRCC check status on reset line id %lu, bit %u\n", id, bit);
+	val = readl(base + PRCC_K_RST_STATUS);
+
+	/* Active low so return the inverse value of the bit */
+	return !(val & BIT(bit));
+}
+
+static const struct reset_control_ops u8500_prcc_reset_ops = {
+	.reset = u8500_prcc_reset,
+	.assert = u8500_prcc_reset_assert,
+	.deassert = u8500_prcc_reset_deassert,
+	.status = u8500_prcc_reset_status,
+};
+
+static int u8500_prcc_reset_xlate(struct reset_controller_dev *rcdev,
+				  const struct of_phandle_args *reset_spec)
+{
+	unsigned int prcc_num, bit;
+
+	if (reset_spec->args_count != 2)
+		return -EINVAL;
+
+	prcc_num = reset_spec->args[0];
+	bit = reset_spec->args[1];
+
+	if (prcc_num != 1 && prcc_num != 2 && prcc_num != 3 &&
+	    prcc_num != 5 && prcc_num != 6) {
+		pr_err("%s: invalid PRCC %d\n", __func__, prcc_num);
+		return -EINVAL;
+	}
+
+	pr_debug("located reset line %d at PRCC %d bit %d\n",
+		 PRCC_RESET_LINE(prcc_num, bit), prcc_num, bit);
+
+	return PRCC_RESET_LINE(prcc_num, bit);
+}
+
+void u8500_prcc_reset_init(struct device_node *np, struct u8500_prcc_reset *ur)
+{
+	struct reset_controller_dev *rcdev = &ur->rcdev;
+	int ret;
+	int i;
+
+	for (i = 0; i < CLKRST_MAX; i++) {
+		ur->base[i] = ioremap(ur->phy_base[i], SZ_4K);
+		if (!ur->base[i])
+			pr_err("PRCC failed to remap for reset base %d (%08x)\n",
+			       i, ur->phy_base[i]);
+	}
+
+	rcdev->owner = THIS_MODULE;
+	rcdev->ops = &u8500_prcc_reset_ops;
+	rcdev->of_node = np;
+	rcdev->of_reset_n_cells = 2;
+	rcdev->of_xlate = u8500_prcc_reset_xlate;
+
+	ret = reset_controller_register(rcdev);
+	if (ret)
+		pr_err("PRCC failed to register reset controller\n");
+}
diff --git a/drivers/clk/ux500/reset-prcc.h b/drivers/clk/ux500/reset-prcc.h
new file mode 100644
index 000000000000..353c9719f2e6
--- /dev/null
+++ b/drivers/clk/ux500/reset-prcc.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __RESET_PRCC_H
+#define __RESET_PRCC_H
+
+#include <linux/reset-controller.h>
+#include <linux/io.h>
+
+/**
+ * struct u8500_prcc_reset - U8500 PRCC reset controller state
+ * @rcdev: reset controller device
+ * @phy_base: the physical base address for each PRCC block
+ * @base: the remapped PRCC bases
+ */
+struct u8500_prcc_reset {
+	struct reset_controller_dev rcdev;
+	u32 phy_base[CLKRST_MAX];
+	void __iomem *base[CLKRST_MAX];
+};
+
+void u8500_prcc_reset_init(struct device_node *np, struct u8500_prcc_reset *ur);
+
+#endif
diff --git a/drivers/clk/ux500/u8500_of_clk.c b/drivers/clk/ux500/u8500_of_clk.c
index 528c5bb397cc..e86ed2eec3fd 100644
--- a/drivers/clk/ux500/u8500_of_clk.c
+++ b/drivers/clk/ux500/u8500_of_clk.c
@@ -10,10 +10,10 @@
 #include <linux/of_address.h>
 #include <linux/clk-provider.h>
 #include <linux/mfd/dbx500-prcmu.h>
-#include "clk.h"
 
-#define PRCC_NUM_PERIPH_CLUSTERS 6
-#define PRCC_PERIPHS_PER_CLUSTER 32
+#include "clk.h"
+#include "prcc.h"
+#include "reset-prcc.h"
 
 static struct clk *prcmu_clk[PRCMU_NUM_CLKS];
 static struct clk *prcc_pclk[(PRCC_NUM_PERIPH_CLUSTERS + 1) * PRCC_PERIPHS_PER_CLUSTER];
@@ -46,16 +46,6 @@ static struct clk *ux500_twocell_get(struct of_phandle_args *clkspec,
 	return PRCC_SHOW(clk_data, base, bit);
 }
 
-/* CLKRST4 is missing making it hard to index things */
-enum clkrst_index {
-	CLKRST1_INDEX = 0,
-	CLKRST2_INDEX,
-	CLKRST3_INDEX,
-	CLKRST5_INDEX,
-	CLKRST6_INDEX,
-	CLKRST_MAX,
-};
-
 static void u8500_clk_init(struct device_node *np)
 {
 	struct prcmu_fw_version *fw_version;
@@ -63,8 +53,18 @@ static void u8500_clk_init(struct device_node *np)
 	const char *sgaclk_parent = NULL;
 	struct clk *clk, *rtc_clk, *twd_clk;
 	u32 bases[CLKRST_MAX];
+	struct u8500_prcc_reset *rstc;
 	int i;
 
+	/*
+	 * We allocate the reset controller here so that we can fill in the
+	 * base addresses properly and pass to the reset controller init
+	 * function later on.
+	 */
+	rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
+	if (!rstc)
+		return;
+
 	for (i = 0; i < ARRAY_SIZE(bases); i++) {
 		struct resource r;
 
@@ -73,6 +73,7 @@ static void u8500_clk_init(struct device_node *np)
 			pr_err("failed to get CLKRST %d base address\n",
 			       i + 1);
 		bases[i] = r.start;
+		rstc->phy_base[i] = r.start;
 	}
 
 	/* Clock sources */
@@ -563,6 +564,9 @@ static void u8500_clk_init(struct device_node *np)
 
 		if (of_node_name_eq(child, "smp-twd-clock"))
 			of_clk_add_provider(child, of_clk_src_simple_get, twd_clk);
+
+		if (of_node_name_eq(child, "prcc-reset-controller"))
+			u8500_prcc_reset_init(child, rstc);
 	}
 }
 CLK_OF_DECLARE(u8500_clks, "stericsson,u8500-clks", u8500_clk_init);