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Subject[PATCH v2 2/2] reset: Add Broadcom STB SW_INIT reset controller driver
Date
Add support for resetting blocks through the Linux reset controller
subsystem when reset lines are provided through a SW_INIT-style reset
controller on Broadcom STB SoCs.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
drivers/reset/Kconfig | 7 ++
drivers/reset/Makefile | 1 +
drivers/reset/reset-brcmstb.c | 130 ++++++++++++++++++++++++++++++++++
3 files changed, 138 insertions(+)
create mode 100644 drivers/reset/reset-brcmstb.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 2e01bd833ffd..1ca03c57e049 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -40,6 +40,13 @@ config RESET_BERLIN
help
This enables the reset controller driver for Marvell Berlin SoCs.

+config RESET_BRCMSTB
+ bool "Broadcom STB reset controller" if COMPILE_TEST
+ default ARCH_BRCMSTB
+ help
+ This enables the reset controller driver for Broadcom STB SoCs using
+ a SUN_TOP_CTRL_SW_INIT style controller.
+
config RESET_HSDK
bool "Synopsys HSDK Reset Driver"
depends on HAS_IOMEM
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index dc7874df78d9..7395db2cb1dd 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
obj-$(CONFIG_RESET_AXS10X) += reset-axs10x.o
obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
+obj-$(CONFIG_RESET_BRCMSTB) += reset-brcmstb.o
obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
obj-$(CONFIG_RESET_LANTIQ) += reset-lantiq.o
diff --git a/drivers/reset/reset-brcmstb.c b/drivers/reset/reset-brcmstb.c
new file mode 100644
index 000000000000..01ab1f71518b
--- /dev/null
+++ b/drivers/reset/reset-brcmstb.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Broadcom STB generic reset controller for SW_INIT style reset controller
+ *
+ * Author: Florian Fainelli <f.fainelli@gmail.com>
+ * Copyright (C) 2018 Broadcom
+ */
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/types.h>
+
+struct brcmstb_reset {
+ void __iomem *base;
+ struct reset_controller_dev rcdev;
+};
+
+#define SW_INIT_SET 0x00
+#define SW_INIT_CLEAR 0x04
+#define SW_INIT_STATUS 0x08
+
+#define SW_INIT_BIT(id) BIT((id) & 0x1f)
+#define SW_INIT_BANK(id) ((id) >> 5)
+
+/* A full bank contains extra registers that we are not utilizing but still
+ * qualify as a single bank.
+ */
+#define SW_INIT_BANK_SIZE 0x18
+
+static inline
+struct brcmstb_reset *to_brcmstb(struct reset_controller_dev *rcdev)
+{
+ return container_of(rcdev, struct brcmstb_reset, rcdev);
+}
+
+static int brcmstb_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
+ struct brcmstb_reset *priv = to_brcmstb(rcdev);
+
+ writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_SET);
+
+ return 0;
+}
+
+static int brcmstb_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
+ struct brcmstb_reset *priv = to_brcmstb(rcdev);
+
+ writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_CLEAR);
+ /* Maximum reset delay after de-asserting a line and seeing block
+ * operation is typically 14us for the worst case, build some slack
+ * here.
+ */
+ usleep_range(100, 200);
+
+ return 0;
+}
+
+static int brcmstb_reset_status(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
+ struct brcmstb_reset *priv = to_brcmstb(rcdev);
+
+ return readl_relaxed(priv->base + off + SW_INIT_STATUS) &
+ SW_INIT_BIT(id);
+}
+
+static const struct reset_control_ops brcmstb_reset_ops = {
+ .assert = brcmstb_reset_assert,
+ .deassert = brcmstb_reset_deassert,
+ .status = brcmstb_reset_status,
+};
+
+static int brcmstb_reset_probe(struct platform_device *pdev)
+{
+ struct device *kdev = &pdev->dev;
+ struct brcmstb_reset *priv;
+ struct resource *res;
+
+ priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (resource_size(res) % SW_INIT_BANK_SIZE) {
+ dev_err(kdev, "incorrect register range\n");
+ return -EINVAL;
+ }
+
+ priv->base = devm_ioremap_resource(kdev, res);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ dev_set_drvdata(kdev, priv);
+
+ priv->rcdev.owner = THIS_MODULE;
+ priv->rcdev.nr_resets = (resource_size(res) / SW_INIT_BANK_SIZE) * 32;
+ priv->rcdev.ops = &brcmstb_reset_ops;
+ priv->rcdev.of_node = kdev->of_node;
+ /* Use defaults: 1 cell and simple xlate function */
+
+ return devm_reset_controller_register(kdev, &priv->rcdev);
+}
+
+static const struct of_device_id brcmstb_reset_of_match[] = {
+ { .compatible = "brcm,brcmstb-reset" },
+ { /* sentinel */ }
+};
+
+static struct platform_driver brcmstb_reset_driver = {
+ .probe = brcmstb_reset_probe,
+ .driver = {
+ .name = "brcmstb-reset",
+ .of_match_table = brcmstb_reset_of_match,
+ },
+};
+module_platform_driver(brcmstb_reset_driver);
+
+MODULE_AUTHOR("Broadcom");
+MODULE_DESCRIPTION("Broadcom STB reset controller");
+MODULE_LICENSE("GPL");
--
2.17.1
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