[PATCH v1 09/16] reset: starfive-jh7100: Add StarFive JH7100 reset driver

Emil Renner Berthing
2021-10-12T13:42:15Z

Add a driver for the StarFive JH7100 reset controller.

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
---
MAINTAINERS | 7 ++
drivers/reset/Kconfig | 8 ++
drivers/reset/Makefile | 1 +
drivers/reset/reset-starfive-jh7100.c | 164 ++++++++++++++++++++++++++
4 files changed, 180 insertions(+)
create mode 100644 drivers/reset/reset-starfive-jh7100.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d2b95b96f0ec..f7883377895e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17854,6 +17854,13 @@ F: Documentation/devicetree/bindings/clock/starfive,jh7100-clkgen.yaml
F: drivers/clk/starfive/clk-starfive-jh7100.c
F: include/dt-bindings/clock/starfive-jh7100.h

+STARFIVE JH7100 RESET CONTROLLER DRIVER
+M: Emil Renner Berthing <kernel@esmil.dk>
+S: Maintained
+F: Documentation/devicetree/bindings/reset/starfive,jh7100-reset.yaml
+F: drivers/reset/reset-starfive-jh7100.c
+F: include/dt-bindings/reset/starfive-jh7100.h
+
STATIC BRANCH/CALL
M: Peter Zijlstra <peterz@infradead.org>
M: Josh Poimboeuf <jpoimboe@redhat.com>
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index be799a5abf8a..8345521744b3 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -92,6 +92,14 @@ config RESET_INTEL_GW
Say Y to control the reset signals provided by reset controller.
Otherwise, say N.

+config RESET_STARFIVE_JH7100
+ bool "StarFive JH7100 Reset Driver"
+ depends on SOC_STARFIVE || COMPILE_TEST
+ depends on OF
+ default SOC_STARFIVE
+ help
+ This enables the reset controller driver for the StarFive JH7100 SoC.
+
config RESET_K210
bool "Reset controller driver for Canaan Kendryte K210 SoC"
depends on (SOC_CANAAN || COMPILE_TEST) && OF
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 21d46d8869ff..021eff3525de 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o
obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
obj-$(CONFIG_RESET_INTEL_GW) += reset-intel-gw.o
+obj-$(CONFIG_RESET_STARFIVE_JH7100) += reset-starfive-jh7100.o
obj-$(CONFIG_RESET_K210) += reset-k210.o
obj-$(CONFIG_RESET_LANTIQ) += reset-lantiq.o
obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o
diff --git a/drivers/reset/reset-starfive-jh7100.c b/drivers/reset/reset-starfive-jh7100.c
new file mode 100644
index 000000000000..26bc5b59c1f3
--- /dev/null
+++ b/drivers/reset/reset-starfive-jh7100.c
@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Reset driver for the StarFive JH7100 SoC
+ *
+ * Copyright (C) 2021 Emil Renner Berthing <kernel@esmil.dk>
+ *
+ */
+
+#include <linux/io.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/spinlock.h>
+
+#include <dt-bindings/reset/starfive-jh7100.h>
+
+/* register offsets */
+#define JH7100_RESET_ASSERT0 0x00
+#define JH7100_RESET_ASSERT1 0x04
+#define JH7100_RESET_ASSERT2 0x08
+#define JH7100_RESET_ASSERT3 0x0c
+#define JH7100_RESET_STATUS0 0x10
+#define JH7100_RESET_STATUS1 0x14
+#define JH7100_RESET_STATUS2 0x18
+#define JH7100_RESET_STATUS3 0x1c
+
+struct jh7100_reset {
+ struct reset_controller_dev rcdev;
+ /* protect registers against overlapping read-modify-write */
+ spinlock_t lock;
+ void __iomem *base;
+};
+
+static inline struct jh7100_reset *
+jh7100_reset_from(struct reset_controller_dev *rcdev)
+{
+ return container_of(rcdev, struct jh7100_reset, rcdev);
+}
+
+static const u32 jh7100_reset_asserted[4] = {
+ BIT(JH7100_RST_U74 % 32) |
+ BIT(JH7100_RST_VP6_DRESET % 32) |
+ BIT(JH7100_RST_VP6_BRESET % 32),
+
+ BIT(JH7100_RST_HIFI4_DRESET % 32) |
+ BIT(JH7100_RST_HIFI4_BRESET % 32),
+
+ BIT_MASK(JH7100_RST_E24 % 32)
+};
+
+static int jh7100_reset_update(struct reset_controller_dev *rcdev,
+ unsigned long id, bool assert)
+{
+ struct jh7100_reset *data = jh7100_reset_from(rcdev);
+ unsigned long offset = id / 32;
+ void __iomem *reg_assert = data->base + JH7100_RESET_ASSERT0 + 4 * offset;
+ void __iomem *reg_status = data->base + JH7100_RESET_STATUS0 + 4 * offset;
+ u32 mask = BIT(id % 32);
+ u32 done = jh7100_reset_asserted[offset] & mask;
+ unsigned long flags;
+ u32 value;
+
+ if (!assert)
+ done ^= mask;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ value = readl(reg_assert);
+ if (assert)
+ value |= mask;
+ else
+ value &= ~mask;
+ writel(value, reg_assert);
+
+ do {
+ value = readl(reg_status) & mask;
+ } while (value != done);
+
+ spin_unlock_irqrestore(&data->lock, flags);
+ return 0;
+}
+
+static int jh7100_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ dev_dbg(rcdev->dev, "assert(%lu)\n", id);
+ return jh7100_reset_update(rcdev, id, true);
+}
+
+static int jh7100_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ dev_dbg(rcdev->dev, "deassert(%lu)\n", id);
+ return jh7100_reset_update(rcdev, id, false);
+}
+
+static int jh7100_reset_reset(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ int ret;
+
+ dev_dbg(rcdev->dev, "reset(%lu)\n", id);
+ ret = jh7100_reset_assert(rcdev, id);
+ if (ret)
+ return ret;
+
+ return jh7100_reset_deassert(rcdev, id);
+}
+
+static int jh7100_reset_status(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct jh7100_reset *data = jh7100_reset_from(rcdev);
+ unsigned long offset = id / 32;
+ void __iomem *reg_status = data->base + JH7100_RESET_STATUS0 + 4 * offset;
+ u32 mask = BIT(id % 32);
+ u32 value = (readl(reg_status) ^ jh7100_reset_asserted[offset]) & mask;
+
+ dev_dbg(rcdev->dev, "status(%lu) = %d\n", id, !value);
+ return !value;
+}
+
+static const struct reset_control_ops jh7100_reset_ops = {
+ .assert = jh7100_reset_assert,
+ .deassert = jh7100_reset_deassert,
+ .reset = jh7100_reset_reset,
+ .status = jh7100_reset_status,
+};
+
+static int jh7100_reset_probe(struct platform_device *pdev)
+{
+ struct jh7100_reset *data;
+
+ data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(data->base))
+ return PTR_ERR(data->base);
+
+ data->rcdev.ops = &jh7100_reset_ops;
+ data->rcdev.owner = THIS_MODULE;
+ data->rcdev.nr_resets = JH7100_RSTN_END;
+ data->rcdev.dev = &pdev->dev;
+ data->rcdev.of_node = pdev->dev.of_node;
+ spin_lock_init(&data->lock);
+
+ return devm_reset_controller_register(&pdev->dev, &data->rcdev);
+}
+
+static const struct of_device_id jh7100_reset_dt_ids[] = {
+ { .compatible = "starfive,jh7100-reset" },
+ { /* sentinel */ },
+};
+
+static struct platform_driver jh7100_reset_driver = {
+ .probe = jh7100_reset_probe,
+ .driver = {
+ .name = "jh7100-reset",
+ .of_match_table = jh7100_reset_dt_ids,
+ },
+};
+builtin_platform_driver(jh7100_reset_driver);
--
2.33.0