[PATCH v6 6/7] clk: baikal-t1: Add DDR/PCIe directly controlled resets support

[Serge Semin <Sergey.Semin@baikalelectronics.ru>]

Aside with a set of the trigger-like resets Baikal-T1 CCU provides two
additional blocks with directly controlled reset signals. In particular it
concerns DDR full and initial resets and various PCIe sub-domains resets.
Let's add the direct reset assertion/de-assertion of the corresponding
flags support into the Baikal-T1 CCU driver then. It will be required at
least for the PCIe platform driver. Obviously the DDR controller isn't
supposed to be fully reset in the kernel, so the corresponding controls
are added just for the sake of the interface implementation completeness.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>

---

Changelog v6:
- Refactor the code to support the linear reset IDs only. (@Philipp)
---
 drivers/clk/baikal-t1/ccu-rst.c     | 67 +++++++++++++++++++++++++++++
 drivers/clk/baikal-t1/ccu-rst.h     | 10 +++++
 include/dt-bindings/reset/bt1-ccu.h |  9 ++++
 3 files changed, 86 insertions(+)

diff --git a/drivers/clk/baikal-t1/ccu-rst.c b/drivers/clk/baikal-t1/ccu-rst.c
index 8fd40810d24e..c20aa3e07afb 100644
--- a/drivers/clk/baikal-t1/ccu-rst.c
+++ b/drivers/clk/baikal-t1/ccu-rst.c
@@ -35,18 +35,29 @@
 #define CCU_AXI_HWA_BASE		0x054
 #define CCU_AXI_SRAM_BASE		0x058
 
+#define CCU_SYS_DDR_BASE		0x02c
 #define CCU_SYS_SATA_REF_BASE		0x060
 #define CCU_SYS_APB_BASE		0x064
+#define CCU_SYS_PCIE_BASE		0x144
 
 #define CCU_RST_DELAY_US		1
 
 #define CCU_RST_TRIG(_base, _ofs)		\
 	{					\
+		.type = CCU_RST_TRIG,		\
+		.base = _base,			\
+		.mask = BIT(_ofs),		\
+	}
+
+#define CCU_RST_DIR(_base, _ofs)		\
+	{					\
+		.type = CCU_RST_DIR,		\
 		.base = _base,			\
 		.mask = BIT(_ofs),		\
 	}
 
 struct ccu_rst_info {
+	enum ccu_rst_type type;
 	unsigned int base;
 	unsigned int mask;
 };
@@ -77,8 +88,18 @@ static const struct ccu_rst_info axi_rst_info[] = {
  * well while the Linux kernel is working.
  */
 static const struct ccu_rst_info sys_rst_info[] = {
+
 	[CCU_SYS_SATA_REF_RST] = CCU_RST_TRIG(CCU_SYS_SATA_REF_BASE, 1),
 	[CCU_SYS_APB_RST] = CCU_RST_TRIG(CCU_SYS_APB_BASE, 1),
+	[CCU_SYS_DDR_FULL_RST] = CCU_RST_DIR(CCU_SYS_DDR_BASE, 1),
+	[CCU_SYS_DDR_INIT_RST] = CCU_RST_DIR(CCU_SYS_DDR_BASE, 2),
+	[CCU_SYS_PCIE_PCS_PHY_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 0),
+	[CCU_SYS_PCIE_PIPE0_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 4),
+	[CCU_SYS_PCIE_CORE_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 8),
+	[CCU_SYS_PCIE_PWR_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 9),
+	[CCU_SYS_PCIE_STICKY_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 10),
+	[CCU_SYS_PCIE_NSTICKY_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 11),
+	[CCU_SYS_PCIE_HOT_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 12),
 };
 
 static int ccu_rst_reset(struct reset_controller_dev *rcdev, unsigned long idx)
@@ -86,6 +107,9 @@ static int ccu_rst_reset(struct reset_controller_dev *rcdev, unsigned long idx)
 	struct ccu_rst *rst = to_ccu_rst(rcdev);
 	const struct ccu_rst_info *info = &rst->rsts_info[idx];
 
+	if (info->type != CCU_RST_TRIG)
+		return -EOPNOTSUPP;
+
 	regmap_update_bits(rst->sys_regs, info->base, info->mask, info->mask);
 
 	/* The next delay must be enough to cover all the resets. */
@@ -94,8 +118,51 @@ static int ccu_rst_reset(struct reset_controller_dev *rcdev, unsigned long idx)
 	return 0;
 }
 
+static int ccu_rst_set(struct reset_controller_dev *rcdev,
+		       unsigned long idx, bool high)
+{
+	struct ccu_rst *rst = to_ccu_rst(rcdev);
+	const struct ccu_rst_info *info = &rst->rsts_info[idx];
+
+	if (info->type != CCU_RST_DIR)
+		return high ? -EOPNOTSUPP : 0;
+
+	return regmap_update_bits(rst->sys_regs, info->base,
+				  info->mask, high ? info->mask : 0);
+}
+
+static int ccu_rst_assert(struct reset_controller_dev *rcdev,
+			  unsigned long idx)
+{
+	return ccu_rst_set(rcdev, idx, true);
+}
+
+static int ccu_rst_deassert(struct reset_controller_dev *rcdev,
+			    unsigned long idx)
+{
+	return ccu_rst_set(rcdev, idx, false);
+}
+
+static int ccu_rst_status(struct reset_controller_dev *rcdev,
+			  unsigned long idx)
+{
+	struct ccu_rst *rst = to_ccu_rst(rcdev);
+	const struct ccu_rst_info *info = &rst->rsts_info[idx];
+	u32 val;
+
+	if (info->type != CCU_RST_DIR)
+		return -EOPNOTSUPP;
+
+	regmap_read(rst->sys_regs, info->base, &val);
+
+	return !!(val & info->mask);
+}
+
 static const struct reset_control_ops ccu_rst_ops = {
 	.reset = ccu_rst_reset,
+	.assert = ccu_rst_assert,
+	.deassert = ccu_rst_deassert,
+	.status = ccu_rst_status,
 };
 
 struct ccu_rst *ccu_rst_hw_register(const struct ccu_rst_init_data *rst_init)
diff --git a/drivers/clk/baikal-t1/ccu-rst.h b/drivers/clk/baikal-t1/ccu-rst.h
index 68214d777465..d6e8b2f671f4 100644
--- a/drivers/clk/baikal-t1/ccu-rst.h
+++ b/drivers/clk/baikal-t1/ccu-rst.h
@@ -13,6 +13,16 @@
 
 struct ccu_rst_info;
 
+/*
+ * enum ccu_rst_type - CCU Reset types
+ * @CCU_RST_TRIG: Self-deasserted reset signal.
+ * @CCU_RST_DIR: Directly controlled reset signal.
+ */
+enum ccu_rst_type {
+	CCU_RST_TRIG,
+	CCU_RST_DIR,
+};
+
 /*
  * struct ccu_rst_init_data - CCU Resets initialization data
  * @sys_regs: Baikal-T1 System Controller registers map.
diff --git a/include/dt-bindings/reset/bt1-ccu.h b/include/dt-bindings/reset/bt1-ccu.h
index 3578e83026bc..c691efaa678f 100644
--- a/include/dt-bindings/reset/bt1-ccu.h
+++ b/include/dt-bindings/reset/bt1-ccu.h
@@ -21,5 +21,14 @@
 
 #define CCU_SYS_SATA_REF_RST		0
 #define CCU_SYS_APB_RST			1
+#define CCU_SYS_DDR_FULL_RST		2
+#define CCU_SYS_DDR_INIT_RST		3
+#define CCU_SYS_PCIE_PCS_PHY_RST	4
+#define CCU_SYS_PCIE_PIPE0_RST		5
+#define CCU_SYS_PCIE_CORE_RST		6
+#define CCU_SYS_PCIE_PWR_RST		7
+#define CCU_SYS_PCIE_STICKY_RST		8
+#define CCU_SYS_PCIE_NSTICKY_RST	9
+#define CCU_SYS_PCIE_HOT_RST		10
 
 #endif /* __DT_BINDINGS_RESET_BT1_CCU_H */
-- 
2.35.1