[PATCH v3 10/15] soc: mediatek: mmsys: Add reset controller support for MT8195 vdosys1

[Nancy.Lin]

Among other features the mmsys driver should implement a reset
controller to be able to reset different bits from their space.

For MT8195 vdosys1, many async modules need to reset after
the display pipe stops and restart.

Signed-off-by: Nancy.Lin <nancy.lin at mediatek.com>
---
 drivers/soc/mediatek/mt8195-mmsys.h |  1 +
 drivers/soc/mediatek/mtk-mmsys.c    | 76 +++++++++++++++++++++++++++++
 drivers/soc/mediatek/mtk-mmsys.h    |  1 +
 3 files changed, 78 insertions(+)

diff --git a/drivers/soc/mediatek/mt8195-mmsys.h b/drivers/soc/mediatek/mt8195-mmsys.h
index 0b079cba443f..0b08ac0cf2bf 100644
--- a/drivers/soc/mediatek/mt8195-mmsys.h
+++ b/drivers/soc/mediatek/mt8195-mmsys.h
@@ -123,6 +123,7 @@
 #define MT8195_VDO1_MIXER_SOUT_SEL_IN				0xf68
 #define MT8195_MIXER_SOUT_SEL_IN_FROM_DISP_MIXER		(0 << 0)
 
+#define MT8195_VDO1_SW0_RST_B           0x1d0
 #define MT8195_VDO1_MERGE0_ASYNC_CFG_WD	0xe30
 #define MT8195_VDO1_MERGE1_ASYNC_CFG_WD	0xe40
 #define MT8195_VDO1_MERGE2_ASYNC_CFG_WD	0xe50
diff --git a/drivers/soc/mediatek/mtk-mmsys.c b/drivers/soc/mediatek/mtk-mmsys.c
index e2bcd701ceb0..5e6c116e589a 100644
--- a/drivers/soc/mediatek/mtk-mmsys.c
+++ b/drivers/soc/mediatek/mtk-mmsys.c
@@ -4,10 +4,12 @@
  * Author: James Liao <jamesjj.liao at mediatek.com>
  */
 
+#include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/io.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/reset-controller.h>
 #include <linux/soc/mediatek/mtk-mmsys.h>
 
 #include "mtk-mmsys.h"
@@ -16,6 +18,8 @@
 #include "mt8365-mmsys.h"
 #include "mt8195-mmsys.h"
 
+#define MMSYS_SW_RESET_PER_REG 32
+
 static const struct mtk_mmsys_driver_data mt2701_mmsys_driver_data = {
 	.clk_driver = "clk-mt2701-mm",
 	.routes = mmsys_default_routing_table,
@@ -72,12 +76,15 @@ static const struct mtk_mmsys_driver_data mt8195_vdosys1_driver_data = {
 	.num_routes = ARRAY_SIZE(mmsys_mt8195_routing_table),
 	.config = mmsys_mt8195_config_table,
 	.num_configs = ARRAY_SIZE(mmsys_mt8195_config_table),
+	.sw_reset_start = MT8195_VDO1_SW0_RST_B,
 };
 
 struct mtk_mmsys {
 	void __iomem *regs;
 	const struct mtk_mmsys_driver_data *data;
 	struct cmdq_client_reg cmdq_base;
+	spinlock_t lock; /* protects mmsys_sw_rst_b reg */
+	struct reset_controller_dev rcdev;
 };
 
 void mtk_mmsys_ddp_connect(struct device *dev,
@@ -158,6 +165,63 @@ void mtk_mmsys_ddp_config(struct device *dev, enum mtk_mmsys_config_type config,
 }
 EXPORT_SYMBOL_GPL(mtk_mmsys_ddp_config);
 
+static int mtk_mmsys_reset_update(struct reset_controller_dev *rcdev, unsigned long id,
+				  bool assert)
+{
+	struct mtk_mmsys *mmsys = container_of(rcdev, struct mtk_mmsys, rcdev);
+	unsigned long flags;
+	u32 reg;
+	int i;
+	u32 offset;
+
+	offset = (id / MMSYS_SW_RESET_PER_REG) * sizeof(u32);
+	id = id % MMSYS_SW_RESET_PER_REG;
+
+	spin_lock_irqsave(&mmsys->lock, flags);
+
+	reg = readl_relaxed(mmsys->regs + mmsys->data->sw_reset_start + offset);
+
+	if (assert)
+		reg &= ~BIT(id);
+	else
+		reg |= BIT(id);
+
+	writel_relaxed(reg, mmsys->regs + mmsys->data->sw_reset_start + offset);
+
+	spin_unlock_irqrestore(&mmsys->lock, flags);
+
+	return 0;
+}
+
+static int mtk_mmsys_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	return mtk_mmsys_reset_update(rcdev, id, true);
+}
+
+static int mtk_mmsys_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	return mtk_mmsys_reset_update(rcdev, id, false);
+}
+
+static int mtk_mmsys_reset(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	int ret;
+
+	ret = mtk_mmsys_reset_assert(rcdev, id);
+	if (ret)
+		return ret;
+
+	usleep_range(1000, 1100);
+
+	return mtk_mmsys_reset_deassert(rcdev, id);
+}
+
+static const struct reset_control_ops mtk_mmsys_reset_ops = {
+	.assert = mtk_mmsys_reset_assert,
+	.deassert = mtk_mmsys_reset_deassert,
+	.reset = mtk_mmsys_reset,
+};
+
 static int mtk_mmsys_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -185,6 +249,18 @@ static int mtk_mmsys_probe(struct platform_device *pdev)
 		dev_dbg(dev, "No mediatek,gce-client-reg!\n");
 #endif
 
+	spin_lock_init(&mmsys->lock);
+
+	mmsys->rcdev.owner = THIS_MODULE;
+	mmsys->rcdev.nr_resets = 64;
+	mmsys->rcdev.ops = &mtk_mmsys_reset_ops;
+	mmsys->rcdev.of_node = pdev->dev.of_node;
+	ret = devm_reset_controller_register(&pdev->dev, &mmsys->rcdev);
+	if (ret) {
+		dev_err(&pdev->dev, "Couldn't register mmsys reset controller: %d\n", ret);
+		return ret;
+	}
+
 	platform_set_drvdata(pdev, mmsys);
 
 	clks = platform_device_register_data(&pdev->dev, mmsys->data->clk_driver,
diff --git a/drivers/soc/mediatek/mtk-mmsys.h b/drivers/soc/mediatek/mtk-mmsys.h
index 825857d8d7f4..d84f5cb78f8c 100644
--- a/drivers/soc/mediatek/mtk-mmsys.h
+++ b/drivers/soc/mediatek/mtk-mmsys.h
@@ -100,6 +100,7 @@ struct mtk_mmsys_driver_data {
 	const unsigned int num_routes;
 	const struct mtk_mmsys_config *config;
 	const unsigned int num_configs;
+	u32 sw_reset_start;
 };
 
 /*
-- 
2.18.0