[PATCH v8 2/3] PCI: rockchip: Simplify reset control handling by using reset_control_bulk*() function

[Anand Moon]

Refactor the reset control handling in the Rockchip PCIe driver,
introduce a more robust and efficient method for assert and
deassert reset controller using reset_control_bulk*() API. Using the
reset_control_bulk APIs, the reset handling for the core clocks reset
unit becomes much simpler.

Spilt the reset controller in two groups as per the
 RK3399 TM  17.5.8.1 PCIe Initialization Sequence
    17.5.8.1.1 PCIe as Root Complex.

6. De-assert the PIPE_RESET_N/MGMT_STICKY_RESET_N/MGMT_RESET_N/RESET_N
   simultaneously.

- devm_reset_control_bulk_get_exclusive(): Allows the driver to get all
  resets defined in the DT thereby removing the hardcoded reset names
  in the driver.
- reset_control_bulk_assert(): Allows the driver to assert the resets
  defined in the driver.
- reset_control_bulk_deassert(): Allows the driver to deassert the resets
  defined in the driver.

Signed-off-by: Anand Moon <linux.amoon@xxxxxxxxx>
---
v8: I tried to address reviews and comments from Mani.
    Follow the sequence of De-assert as per the driver code.
    Drop the comment in the driver.
    Improve the commit message with the description of the TMP section.
    Improve the reason for the core functional changes in the commit
    description.
    Improve the error handling messages of the code.
v7: replace devm_reset_control_bulk_get_optional_exclusive()
        with devm_reset_control_bulk_get_exclusive()
    update the functional changes.
V6: Add reason for the split of the RESET pins.
v5: Fix the De-assert reset core as per the TRM
    De-assert the PIPE_RESET_N/MGMT_STICKY_RESET_N/MGMT_RESET_N/RESET_N
    simultaneously.
v4: use dev_err_probe in error path.
v3: Fix typo in commit message, dropped reported by.
v2: Fix compilation error reported by Intel test robot
    fixed checkpatch warning.
---
 drivers/pci/controller/pcie-rockchip.c | 155 +++++--------------------
 drivers/pci/controller/pcie-rockchip.h |  26 +++--
 2 files changed, 49 insertions(+), 132 deletions(-)

diff --git a/drivers/pci/controller/pcie-rockchip.c b/drivers/pci/controller/pcie-rockchip.c
index 2777ef0cb599..43d83c1f3196 100644
--- a/drivers/pci/controller/pcie-rockchip.c
+++ b/drivers/pci/controller/pcie-rockchip.c
@@ -30,7 +30,7 @@ int rockchip_pcie_parse_dt(struct rockchip_pcie *rockchip)
 	struct platform_device *pdev = to_platform_device(dev);
 	struct device_node *node = dev->of_node;
 	struct resource *regs;
-	int err;
+	int err, i;
 
 	if (rockchip->is_rc) {
 		regs = platform_get_resource_byname(pdev,
@@ -69,55 +69,23 @@ int rockchip_pcie_parse_dt(struct rockchip_pcie *rockchip)
 	if (rockchip->link_gen < 0 || rockchip->link_gen > 2)
 		rockchip->link_gen = 2;
 
-	rockchip->core_rst = devm_reset_control_get_exclusive(dev, "core");
-	if (IS_ERR(rockchip->core_rst)) {
-		if (PTR_ERR(rockchip->core_rst) != -EPROBE_DEFER)
-			dev_err(dev, "missing core reset property in node\n");
-		return PTR_ERR(rockchip->core_rst);
-	}
-
-	rockchip->mgmt_rst = devm_reset_control_get_exclusive(dev, "mgmt");
-	if (IS_ERR(rockchip->mgmt_rst)) {
-		if (PTR_ERR(rockchip->mgmt_rst) != -EPROBE_DEFER)
-			dev_err(dev, "missing mgmt reset property in node\n");
-		return PTR_ERR(rockchip->mgmt_rst);
-	}
-
-	rockchip->mgmt_sticky_rst = devm_reset_control_get_exclusive(dev,
-								"mgmt-sticky");
-	if (IS_ERR(rockchip->mgmt_sticky_rst)) {
-		if (PTR_ERR(rockchip->mgmt_sticky_rst) != -EPROBE_DEFER)
-			dev_err(dev, "missing mgmt-sticky reset property in node\n");
-		return PTR_ERR(rockchip->mgmt_sticky_rst);
-	}
-
-	rockchip->pipe_rst = devm_reset_control_get_exclusive(dev, "pipe");
-	if (IS_ERR(rockchip->pipe_rst)) {
-		if (PTR_ERR(rockchip->pipe_rst) != -EPROBE_DEFER)
-			dev_err(dev, "missing pipe reset property in node\n");
-		return PTR_ERR(rockchip->pipe_rst);
-	}
+	for (i = 0; i < ROCKCHIP_NUM_PM_RSTS; i++)
+		rockchip->pm_rsts[i].id = rockchip_pci_pm_rsts[i];
 
-	rockchip->pm_rst = devm_reset_control_get_exclusive(dev, "pm");
-	if (IS_ERR(rockchip->pm_rst)) {
-		if (PTR_ERR(rockchip->pm_rst) != -EPROBE_DEFER)
-			dev_err(dev, "missing pm reset property in node\n");
-		return PTR_ERR(rockchip->pm_rst);
-	}
+	err = devm_reset_control_bulk_get_exclusive(dev,
+						    ROCKCHIP_NUM_PM_RSTS,
+						    rockchip->pm_rsts);
+	if (err)
+		return dev_err_probe(dev, err, "Cannot get the PM reset control\n");
 
-	rockchip->pclk_rst = devm_reset_control_get_exclusive(dev, "pclk");
-	if (IS_ERR(rockchip->pclk_rst)) {
-		if (PTR_ERR(rockchip->pclk_rst) != -EPROBE_DEFER)
-			dev_err(dev, "missing pclk reset property in node\n");
-		return PTR_ERR(rockchip->pclk_rst);
-	}
+	for (i = 0; i < ROCKCHIP_NUM_CORE_RSTS; i++)
+		rockchip->core_rsts[i].id = rockchip_pci_core_rsts[i];
 
-	rockchip->aclk_rst = devm_reset_control_get_exclusive(dev, "aclk");
-	if (IS_ERR(rockchip->aclk_rst)) {
-		if (PTR_ERR(rockchip->aclk_rst) != -EPROBE_DEFER)
-			dev_err(dev, "missing aclk reset property in node\n");
-		return PTR_ERR(rockchip->aclk_rst);
-	}
+	err = devm_reset_control_bulk_get_exclusive(dev,
+						    ROCKCHIP_NUM_CORE_RSTS,
+						    rockchip->core_rsts);
+	if (err)
+		return dev_err_probe(dev, err, "Cannot get the CORE reset control\n");
 
 	if (rockchip->is_rc) {
 		rockchip->ep_gpio = devm_gpiod_get_optional(dev, "ep",
@@ -147,23 +115,10 @@ int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
 	int err, i;
 	u32 regs;
 
-	err = reset_control_assert(rockchip->aclk_rst);
-	if (err) {
-		dev_err(dev, "assert aclk_rst err %d\n", err);
-		return err;
-	}
-
-	err = reset_control_assert(rockchip->pclk_rst);
-	if (err) {
-		dev_err(dev, "assert pclk_rst err %d\n", err);
-		return err;
-	}
-
-	err = reset_control_assert(rockchip->pm_rst);
-	if (err) {
-		dev_err(dev, "assert pm_rst err %d\n", err);
-		return err;
-	}
+	err = reset_control_bulk_assert(ROCKCHIP_NUM_PM_RSTS,
+					rockchip->pm_rsts);
+	if (err)
+		return dev_err_probe(dev, err, "Couldn't assert PM resets\n");
 
 	for (i = 0; i < MAX_LANE_NUM; i++) {
 		err = phy_init(rockchip->phys[i]);
@@ -173,47 +128,17 @@ int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
 		}
 	}
 
-	err = reset_control_assert(rockchip->core_rst);
-	if (err) {
-		dev_err(dev, "assert core_rst err %d\n", err);
-		goto err_exit_phy;
-	}
-
-	err = reset_control_assert(rockchip->mgmt_rst);
-	if (err) {
-		dev_err(dev, "assert mgmt_rst err %d\n", err);
-		goto err_exit_phy;
-	}
-
-	err = reset_control_assert(rockchip->mgmt_sticky_rst);
-	if (err) {
-		dev_err(dev, "assert mgmt_sticky_rst err %d\n", err);
-		goto err_exit_phy;
-	}
-
-	err = reset_control_assert(rockchip->pipe_rst);
-	if (err) {
-		dev_err(dev, "assert pipe_rst err %d\n", err);
-		goto err_exit_phy;
-	}
+	err = reset_control_bulk_assert(ROCKCHIP_NUM_CORE_RSTS,
+					rockchip->core_rsts);
+	if (err)
+		return dev_err_probe(dev, err, "Couldn't assert Core resets\n");
 
 	udelay(10);
 
-	err = reset_control_deassert(rockchip->pm_rst);
-	if (err) {
-		dev_err(dev, "deassert pm_rst err %d\n", err);
-		goto err_exit_phy;
-	}
-
-	err = reset_control_deassert(rockchip->aclk_rst);
+	err = reset_control_bulk_deassert(ROCKCHIP_NUM_PM_RSTS,
+					  rockchip->pm_rsts);
 	if (err) {
-		dev_err(dev, "deassert aclk_rst err %d\n", err);
-		goto err_exit_phy;
-	}
-
-	err = reset_control_deassert(rockchip->pclk_rst);
-	if (err) {
-		dev_err(dev, "deassert pclk_rst err %d\n", err);
+		dev_err(dev, "Couldn't deassert PM resets %d\n", err);
 		goto err_exit_phy;
 	}
 
@@ -252,35 +177,15 @@ int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
 		goto err_power_off_phy;
 	}
 
-	/*
-	 * Please don't reorder the deassert sequence of the following
-	 * four reset pins.
-	 */
-	err = reset_control_deassert(rockchip->mgmt_sticky_rst);
-	if (err) {
-		dev_err(dev, "deassert mgmt_sticky_rst err %d\n", err);
-		goto err_power_off_phy;
-	}
-
-	err = reset_control_deassert(rockchip->core_rst);
+	err = reset_control_bulk_deassert(ROCKCHIP_NUM_CORE_RSTS,
+					  rockchip->core_rsts);
 	if (err) {
-		dev_err(dev, "deassert core_rst err %d\n", err);
-		goto err_power_off_phy;
-	}
-
-	err = reset_control_deassert(rockchip->mgmt_rst);
-	if (err) {
-		dev_err(dev, "deassert mgmt_rst err %d\n", err);
-		goto err_power_off_phy;
-	}
-
-	err = reset_control_deassert(rockchip->pipe_rst);
-	if (err) {
-		dev_err(dev, "deassert pipe_rst err %d\n", err);
+		dev_err(dev, "Couldn't deassert CORE err %d\n", err);
 		goto err_power_off_phy;
 	}
 
 	return 0;
+
 err_power_off_phy:
 	while (i--)
 		phy_power_off(rockchip->phys[i]);
diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
index bebab80c9553..cc667c73d42f 100644
--- a/drivers/pci/controller/pcie-rockchip.h
+++ b/drivers/pci/controller/pcie-rockchip.h
@@ -15,6 +15,7 @@
 #include <linux/kernel.h>
 #include <linux/pci.h>
 #include <linux/pci-ecam.h>
+#include <linux/reset.h>
 
 /*
  * The upper 16 bits of PCIE_CLIENT_CONFIG are a write mask for the lower 16
@@ -288,18 +289,29 @@
 		(((c) << ((b) * 8 + 5)) & \
 		 ROCKCHIP_PCIE_CORE_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b))
 
+#define ROCKCHIP_NUM_PM_RSTS   ARRAY_SIZE(rockchip_pci_pm_rsts)
+#define ROCKCHIP_NUM_CORE_RSTS ARRAY_SIZE(rockchip_pci_core_rsts)
+
+static const char * const rockchip_pci_pm_rsts[] = {
+	"pm",
+	"pclk",
+	"aclk",
+};
+
+static const char * const rockchip_pci_core_rsts[] = {
+	"mgmt-sticky",
+	"core",
+	"mgmt",
+	"pipe",
+};
+
 struct rockchip_pcie {
 	void	__iomem *reg_base;		/* DT axi-base */
 	void	__iomem *apb_base;		/* DT apb-base */
 	bool    legacy_phy;
 	struct  phy *phys[MAX_LANE_NUM];
-	struct	reset_control *core_rst;
-	struct	reset_control *mgmt_rst;
-	struct	reset_control *mgmt_sticky_rst;
-	struct	reset_control *pipe_rst;
-	struct	reset_control *pm_rst;
-	struct	reset_control *aclk_rst;
-	struct	reset_control *pclk_rst;
+	struct  reset_control_bulk_data pm_rsts[ROCKCHIP_NUM_PM_RSTS];
+	struct  reset_control_bulk_data core_rsts[ROCKCHIP_NUM_CORE_RSTS];
 	struct  clk_bulk_data *clks;
 	int	num_clks;
 	struct	regulator *vpcie12v; /* 12V power supply */
-- 
2.44.0