[PATCH v2] ARC: reset: introduce HSDKv1 reset driver

From: Eugeniy Paltsev
Date: Wed Jul 19 2017 - 14:45:21 EST

The HSDK v1 periphery IPs can be reset by accessing some registers
from the CGU block.

The list of available reset lines is documented in the DT bindings.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
---
Changes v1 -> v2:
- Remove defines of the unused registers.
- Map io memory only for single CGU_SYS_RST_CTRL register instead
of CGU_SYS_*_CTRL, as we use only CGU_SYS_RST_CTRL.


.../bindings/reset/snps,hsdk-v1-reset.txt | 28 +++++
MAINTAINERS | 7 ++
drivers/reset/Kconfig | 6 +
drivers/reset/Makefile | 1 +
drivers/reset/reset-hsdk-v1.c | 137 +++++++++++++++++++++
include/dt-bindings/reset/snps,hsdk-v1-reset.h | 17 +++
6 files changed, 196 insertions(+)
create mode 100644 Documentation/devicetree/bindings/reset/snps,hsdk-v1-reset.txt
create mode 100644 drivers/reset/reset-hsdk-v1.c
create mode 100644 include/dt-bindings/reset/snps,hsdk-v1-reset.h

diff --git a/Documentation/devicetree/bindings/reset/snps,hsdk-v1-reset.txt b/Documentation/devicetree/bindings/reset/snps,hsdk-v1-reset.txt
new file mode 100644
index 0000000..6a68146
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/snps,hsdk-v1-reset.txt
@@ -0,0 +1,28 @@
+Binding for the HSDK v1 reset controller
+
+This binding uses the common reset binding[1].
+
+[1] Documentation/devicetree/bindings/reset/reset.txt
+
+Required properties:
+- compatible: should be "snps,hsdk-v1.0-reset".
+- reg: should always contain 2 pairs address - length: first for reset
+ configuration register and second for corresponding SW reset and status bits
+ register.
+- #reset-cells: from common reset binding; Should always be set to 1.
+
+Example:
+ reset: reset@880 {
+ compatible = "snps,hsdk-v1.0-reset";
+ #reset-cells = <1>;
+ reg = <0x8A0 0x4>, <0xFF0 0x4>;
+ };
+
+Specifying reset lines connected to IP modules:
+ ethernet@.... {
+ ....
+ resets = <&reset HSDK_V1_ETH_RESET>;
+ ....
+ };
+
+The index could be found in <dt-bindings/reset/snps,hsdk-v1-reset.h>
diff --git a/MAINTAINERS b/MAINTAINERS
index 09b5ab6..99deabb 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11307,6 +11307,13 @@ L: linux-mmc@xxxxxxxxxxxxxxx
S: Maintained
F: drivers/mmc/host/dw_mmc*

+SYNOPSYS HSDK RESET CONTROLLER DRIVER
+M: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
+S: Supported
+F: drivers/reset/reset-hsdk-v1.c
+F: include/dt-bindings/reset/snps,hsdk-v1-reset.h
+F: Documentation/devicetree/bindings/reset/snps,hsdk-v1-reset.txt
+
SYSTEM TRACE MODULE CLASS
M: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
S: Maintained
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index d21c07c..cb13f0d 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -34,6 +34,12 @@ config RESET_BERLIN
help
This enables the reset controller driver for Marvell Berlin SoCs.

+config RESET_HSDK_V1
+ bool "HSDK v1 Reset Driver"
+ default n
+ help
+ This enables the reset controller driver for HSDK v1.
+
config RESET_IMX7
bool "i.MX7 Reset Driver" if COMPILE_TEST
default SOC_IMX7D
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 02a74db..772e5f2 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -5,6 +5,7 @@ obj-$(CONFIG_ARCH_TEGRA) += tegra/
obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
+obj-$(CONFIG_RESET_HSDK_V1) += reset-hsdk-v1.o
obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o
obj-$(CONFIG_RESET_MESON) += reset-meson.o
diff --git a/drivers/reset/reset-hsdk-v1.c b/drivers/reset/reset-hsdk-v1.c
new file mode 100644
index 0000000..bca13e4
--- /dev/null
+++ b/drivers/reset/reset-hsdk-v1.c
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2017 Synopsys.
+ *
+ * Synopsys HSDKv1 SDP reset driver.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#define to_hsdkv1_rst(p) container_of((p), struct hsdkv1_rst, rcdev)
+
+struct hsdkv1_rst {
+ void __iomem *regs_ctl;
+ void __iomem *regs_rst;
+ spinlock_t lock;
+ struct reset_controller_dev rcdev;
+};
+
+static const u32 rst_map[] = {
+ BIT(16), /* APB_RST */
+ BIT(17), /* AXI_RST */
+ BIT(18), /* ETH_RST */
+ BIT(19), /* USB_RST */
+ BIT(20), /* SDIO_RST */
+ BIT(21), /* HDMI_RST */
+ BIT(22), /* GFX_RST */
+ BIT(25), /* DMAC_RST */
+ BIT(31), /* EBI_RST */
+};
+
+#define HSDK_MAX_RESETS ARRAY_SIZE(rst_map)
+
+#define CGU_SYS_RST_CTRL 0x0
+#define CGU_IP_SW_RESET 0x0
+#define CGU_IP_SW_RESET_DELAY_SHIFT 16
+#define CGU_IP_SW_RESET_DELAY_MASK GENMASK(31, CGU_IP_SW_RESET_DELAY_SHIFT)
+#define CGU_IP_SW_RESET_DELAY 0
+#define CGU_IP_SW_RESET_RESET BIT(0)
+#define SW_RESET_TIMEOUT 10000
+
+static void hsdkv1_reset_config(struct hsdkv1_rst *rst, unsigned long id)
+{
+ writel(rst_map[id], rst->regs_ctl + CGU_SYS_RST_CTRL);
+}
+
+static int hsdkv1_reset_do(struct hsdkv1_rst *rst)
+{
+ u32 reg;
+
+ reg = readl(rst->regs_rst + CGU_IP_SW_RESET);
+ reg &= ~CGU_IP_SW_RESET_DELAY_MASK;
+ reg |= CGU_IP_SW_RESET_DELAY << CGU_IP_SW_RESET_DELAY_SHIFT;
+ reg |= CGU_IP_SW_RESET_RESET;
+ writel(reg, rst->regs_rst + CGU_IP_SW_RESET);
+
+ /* wait till reset bit is back to 0 */
+ return readl_poll_timeout_atomic(rst->regs_rst + CGU_IP_SW_RESET, reg,
+ !(reg & CGU_IP_SW_RESET_RESET), 5, SW_RESET_TIMEOUT);
+}
+
+static int hsdkv1_reset_reset(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct hsdkv1_rst *rst = to_hsdkv1_rst(rcdev);
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&rst->lock, flags);
+ hsdkv1_reset_config(rst, id);
+ ret = hsdkv1_reset_do(rst);
+ spin_unlock_irqrestore(&rst->lock, flags);
+
+ return ret;
+}
+
+static const struct reset_control_ops hsdkv1_reset_ops = {
+ .reset = hsdkv1_reset_reset,
+};
+
+static int hsdkv1_reset_probe(struct platform_device *pdev)
+{
+ struct hsdkv1_rst *rst;
+ struct resource *mem;
+
+ rst = devm_kzalloc(&pdev->dev, sizeof(*rst), GFP_KERNEL);
+ if (!rst)
+ return -ENOMEM;
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ rst->regs_ctl = devm_ioremap_resource(&pdev->dev, mem);
+ if (IS_ERR(rst->regs_ctl))
+ return PTR_ERR(rst->regs_ctl);
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ rst->regs_rst = devm_ioremap_resource(&pdev->dev, mem);
+ if (IS_ERR(rst->regs_rst))
+ return PTR_ERR(rst->regs_rst);
+
+ spin_lock_init(&rst->lock);
+
+ rst->rcdev.owner = THIS_MODULE;
+ rst->rcdev.ops = &hsdkv1_reset_ops;
+ rst->rcdev.of_node = pdev->dev.of_node;
+ rst->rcdev.nr_resets = HSDK_MAX_RESETS;
+ rst->rcdev.of_reset_n_cells = 1;
+
+ return reset_controller_register(&rst->rcdev);
+}
+
+static const struct of_device_id hsdkv1_reset_dt_match[] = {
+ { .compatible = "snps,hsdk-v1.0-reset" },
+ { },
+};
+
+static struct platform_driver hsdkv1_reset_driver = {
+ .probe = hsdkv1_reset_probe,
+ .driver = {
+ .name = "hsdk-v1.0-reset",
+ .of_match_table = hsdkv1_reset_dt_match,
+ },
+};
+builtin_platform_driver(hsdkv1_reset_driver);
+
+MODULE_AUTHOR("Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Synopsys HSDKv1 SDP reset driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/dt-bindings/reset/snps,hsdk-v1-reset.h b/include/dt-bindings/reset/snps,hsdk-v1-reset.h
new file mode 100644
index 0000000..d898c89
--- /dev/null
+++ b/include/dt-bindings/reset/snps,hsdk-v1-reset.h
@@ -0,0 +1,17 @@
+/**
+ * This header provides index for the HSDK v1 reset controller.
+ */
+#ifndef _DT_BINDINGS_RESET_CONTROLLER_HSDK_V1
+#define _DT_BINDINGS_RESET_CONTROLLER_HSDK_V1
+
+#define HSDK_V1_APB_RESET 0
+#define HSDK_V1_AXI_RESET 1
+#define HSDK_V1_ETH_RESET 2
+#define HSDK_V1_USB_RESET 3
+#define HSDK_V1_SDIO_RESET 4
+#define HSDK_V1_HDMI_RESET 5
+#define HSDK_V1_GFX_RESET 6
+#define HSDK_V1_DMAC_RESET 7
+#define HSDK_V1_EBI_RESET 8
+
+#endif /*_DT_BINDINGS_RESET_CONTROLLER_HSDK_V1*/
--
2.9.3