[PATCH v4 7/8] clk: baikal-t1: Add DDR/PCIe directly controlled resets support

From: Serge Semin
Date: Fri Jun 10 2022 - 03:22:33 EST

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@xxxxxxxxxxxxxxxxxxxx>
---
drivers/clk/baikal-t1/ccu-rst.c | 56 +++++++++++++++++++++++++++++
drivers/clk/baikal-t1/ccu-rst.h | 12 +++++++
drivers/clk/baikal-t1/clk-ccu-rst.c | 21 +++++++++++
include/dt-bindings/reset/bt1-ccu.h | 9 +++++
4 files changed, 98 insertions(+)

diff --git a/drivers/clk/baikal-t1/ccu-rst.c b/drivers/clk/baikal-t1/ccu-rst.c
index b355bf0b399a..a3b41cbe6230 100644
--- a/drivers/clk/baikal-t1/ccu-rst.c
+++ b/drivers/clk/baikal-t1/ccu-rst.c
@@ -30,6 +30,9 @@ static int ccu_rst_reset(struct reset_controller_dev *rcdev, unsigned long idx)
return PTR_ERR(rst);
}

+ if (rst->type != CCU_RST_TRIG)
+ return -EOPNOTSUPP;
+
regmap_update_bits(rst->sys_regs, rst->reg_ctl, rst->mask, rst->mask);

/* The next delay must be enough to cover all the resets. */
@@ -38,6 +41,59 @@ 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;
+
+ rst = ccu_rst_get_desc(rcdev, idx);
+ if (IS_ERR(rst)) {
+ pr_err("Invalid reset index %lu specified\n", idx);
+ return PTR_ERR(rst);
+ }
+
+ if (rst->type != CCU_RST_DIR)
+ return high ? -EOPNOTSUPP : 0;
+
+ return regmap_update_bits(rst->sys_regs, rst->reg_ctl,
+ rst->mask, high ? rst->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;
+ u32 val;
+
+ rst = ccu_rst_get_desc(rcdev, idx);
+ if (IS_ERR(rst)) {
+ pr_err("Invalid reset index %lu specified\n", idx);
+ return PTR_ERR(rst);
+ }
+
+ if (rst->type != CCU_RST_DIR)
+ return -EOPNOTSUPP;
+
+ regmap_read(rst->sys_regs, rst->reg_ctl, &val);
+
+ return !!(val & rst->mask);
+}
+
const struct reset_control_ops ccu_rst_ops = {
.reset = ccu_rst_reset,
+ .assert = ccu_rst_assert,
+ .deassert = ccu_rst_deassert,
+ .status = ccu_rst_status,
};
diff --git a/drivers/clk/baikal-t1/ccu-rst.h b/drivers/clk/baikal-t1/ccu-rst.h
index d03bae4b7a05..7b9b9c81f5c9 100644
--- a/drivers/clk/baikal-t1/ccu-rst.h
+++ b/drivers/clk/baikal-t1/ccu-rst.h
@@ -12,6 +12,16 @@

struct ccu_rst_data;

+/*
+ * 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.
@@ -25,12 +35,14 @@ struct ccu_rst_init_data {
/*
* struct ccu_rst - CCU Reset descriptor
* @id: Reset identifier.
+ * @type: Reset control type.
* @reg_ctl: Reset control register base address.
* @sys_regs: Baikal-T1 System Controller registers map.
* @mask: Reset bitmask (normally it's just a single bit flag).
*/
struct ccu_rst {
unsigned int id;
+ enum ccu_rst_type type;
unsigned int reg_ctl;
struct regmap *sys_regs;
u32 mask;
diff --git a/drivers/clk/baikal-t1/clk-ccu-rst.c b/drivers/clk/baikal-t1/clk-ccu-rst.c
index b10857f48b8b..592a95308c62 100644
--- a/drivers/clk/baikal-t1/clk-ccu-rst.c
+++ b/drivers/clk/baikal-t1/clk-ccu-rst.c
@@ -33,18 +33,30 @@
#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_TRIG(_id, _base, _ofs) \
{ \
.id = _id, \
+ .type = CCU_RST_TRIG, \
+ .base = _base, \
+ .mask = BIT(_ofs), \
+ }
+
+#define CCU_RST_DIR(_id, _base, _ofs) \
+ { \
+ .id = _id, \
+ .type = CCU_RST_DIR, \
.base = _base, \
.mask = BIT(_ofs), \
}

struct ccu_rst_info {
unsigned int id;
+ enum ccu_rst_type type;
unsigned int base;
unsigned int mask;
};
@@ -89,6 +101,15 @@ static const struct ccu_rst_info axi_rst_info[] = {
static const struct ccu_rst_info sys_rst_info[] = {
CCU_RST_TRIG(CCU_SYS_SATA_REF_RST, CCU_SYS_SATA_REF_BASE, 1),
CCU_RST_TRIG(CCU_SYS_APB_RST, CCU_SYS_APB_BASE, 1),
+ CCU_RST_DIR(CCU_SYS_DDR_FULL_RST, CCU_SYS_DDR_BASE, 1),
+ CCU_RST_DIR(CCU_SYS_DDR_INIT_RST, CCU_SYS_DDR_BASE, 2),
+ CCU_RST_DIR(CCU_SYS_PCIE_PCS_PHY_RST, CCU_SYS_PCIE_BASE, 0),
+ CCU_RST_DIR(CCU_SYS_PCIE_PIPE0_RST, CCU_SYS_PCIE_BASE, 4),
+ CCU_RST_DIR(CCU_SYS_PCIE_CORE_RST, CCU_SYS_PCIE_BASE, 8),
+ CCU_RST_DIR(CCU_SYS_PCIE_PWR_RST, CCU_SYS_PCIE_BASE, 9),
+ CCU_RST_DIR(CCU_SYS_PCIE_STICKY_RST, CCU_SYS_PCIE_BASE, 10),
+ CCU_RST_DIR(CCU_SYS_PCIE_NSTICKY_RST, CCU_SYS_PCIE_BASE, 11),
+ CCU_RST_DIR(CCU_SYS_PCIE_HOT_RST, CCU_SYS_PCIE_BASE, 12),
};

struct ccu_rst *ccu_rst_get_desc(struct reset_controller_dev *rcdev, unsigned long idx)
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