Add support for resetting blocks through the Linux reset controller
subsystem for BCM63xx SoCs.
Signed-off-by: Álvaro Fernández Rojas <noltari@xxxxxxxxx>
Reviewed-by: Florian Fainelli <F.fainelli@xxxxxxxxx>
Reviewed-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
---
v7: introduce changes suggested by Philipp:
- sort Kconfig alphabetically.
- return 0 on bcm6345_reset_update.
- add second sleep comment.
v6: driver improvements:
- use devm_platform_ioremap_resource.
- simplify bcm6345_reset_probe return.
- introduce and use to_bcm6345_reset function.
v5: fix kbuild robot error (drop __init).
v4: no changes.
v3: using reset-simple isn't possible since sleeping after performing the
reset is also needed.
v2: add compatibility to reset-simple instead of adding a new driver.
drivers/reset/Kconfig | 7 ++
drivers/reset/Makefile | 1 +
drivers/reset/reset-bcm6345.c | 135 ++++++++++++++++++++++++++++++++++
3 files changed, 143 insertions(+)
create mode 100644 drivers/reset/reset-bcm6345.c
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index d9efbfd29646..6b9625a40799 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -35,6 +35,13 @@ config RESET_AXS10X
help
This enables the reset controller driver for AXS10x.
+config RESET_BCM6345
+ bool "BCM6345 Reset Controller"
+ depends on BMIPS_GENERIC || COMPILE_TEST
+ default BMIPS_GENERIC
+ help
+ This enables the reset controller driver for BCM6345 SoCs.
+
config RESET_BERLIN
bool "Berlin Reset Driver" if COMPILE_TEST
default ARCH_BERLIN
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 249ed357c997..e642aae42f0f 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_ARCH_TEGRA) += tegra/
obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
obj-$(CONFIG_RESET_AXS10X) += reset-axs10x.o
+obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
obj-$(CONFIG_RESET_BRCMSTB) += reset-brcmstb.o
obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o
diff --git a/drivers/reset/reset-bcm6345.c b/drivers/reset/reset-bcm6345.c
new file mode 100644
index 000000000000..737e4e81f6b7
--- /dev/null
+++ b/drivers/reset/reset-bcm6345.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * BCM6345 Reset Controller Driver
+ *
+ * Copyright (C) 2020 Álvaro Fernández Rojas <noltari@xxxxxxxxx>
+ */
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+
+#define BCM6345_RESET_NUM 32
+#define BCM6345_RESET_SLEEP_MIN_US 10000
+#define BCM6345_RESET_SLEEP_MAX_US 20000
+
+struct bcm6345_reset {
+ struct reset_controller_dev rcdev;
+ void __iomem *base;
+ spinlock_t lock;
+};
+
+static inline struct bcm6345_reset *
+to_bcm6345_reset(struct reset_controller_dev *rcdev)
+{
+ return container_of(rcdev, struct bcm6345_reset, rcdev);
+}
+
+static int bcm6345_reset_update(struct reset_controller_dev *rcdev,
+ unsigned long id, bool assert)
+{
+ struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);
+ unsigned long flags;
+ uint32_t val;
+
+ spin_lock_irqsave(&bcm6345_reset->lock, flags);
+ val = __raw_readl(bcm6345_reset->base);
+ if (assert)
+ val &= ~BIT(id);
+ else
+ val |= BIT(id);
+ __raw_writel(val, bcm6345_reset->base);
+ spin_unlock_irqrestore(&bcm6345_reset->lock, flags);
+
+ return 0;
+}
+
+static int bcm6345_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return bcm6345_reset_update(rcdev, id, true);
+}
+
+static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return bcm6345_reset_update(rcdev, id, false);
+}
+
+static int bcm6345_reset_reset(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ bcm6345_reset_update(rcdev, id, true);
+ usleep_range(BCM6345_RESET_SLEEP_MIN_US,
+ BCM6345_RESET_SLEEP_MAX_US);
+
+ bcm6345_reset_update(rcdev, id, false);
+ /*
+ * Ensure component is taken out reset state by sleeping also after
+ * deasserting the reset. Otherwise, the component may not be ready
+ * for operation.
+ */
+ usleep_range(BCM6345_RESET_SLEEP_MIN_US,
+ BCM6345_RESET_SLEEP_MAX_US);
+
+ return 0;
+}
+
+static int bcm6345_reset_status(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);
+
+ return !(__raw_readl(bcm6345_reset->base) & BIT(id));
+}
+
+static struct reset_control_ops bcm6345_reset_ops = {
+ .assert = bcm6345_reset_assert,
+ .deassert = bcm6345_reset_deassert,
+ .reset = bcm6345_reset_reset,
+ .status = bcm6345_reset_status,
+};
+
+static int bcm6345_reset_probe(struct platform_device *pdev)
+{
+ struct bcm6345_reset *bcm6345_reset;
+
+ bcm6345_reset = devm_kzalloc(&pdev->dev,
+ sizeof(*bcm6345_reset), GFP_KERNEL);
+ if (!bcm6345_reset)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, bcm6345_reset);
+
+ bcm6345_reset->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(bcm6345_reset->base))
+ return PTR_ERR(bcm6345_reset->base);
+
+ spin_lock_init(&bcm6345_reset->lock);
+ bcm6345_reset->rcdev.ops = &bcm6345_reset_ops;
+ bcm6345_reset->rcdev.owner = THIS_MODULE;
+ bcm6345_reset->rcdev.of_node = pdev->dev.of_node;
+ bcm6345_reset->rcdev.of_reset_n_cells = 1;
+ bcm6345_reset->rcdev.nr_resets = BCM6345_RESET_NUM;
+
+ return devm_reset_controller_register(&pdev->dev,
+ &bcm6345_reset->rcdev);
+}
+
+static const struct of_device_id bcm6345_reset_of_match[] = {
+ { .compatible = "brcm,bcm6345-reset" },
+ { /* sentinel */ },
+};
+
+static struct platform_driver bcm6345_reset_driver = {
+ .probe = bcm6345_reset_probe,
+ .driver = {
+ .name = "bcm6345-reset",
+ .of_match_table = bcm6345_reset_of_match,
+ .suppress_bind_attrs = true,
+ },
+};
+builtin_platform_driver(bcm6345_reset_driver);
--
2.27.0
