pci: rockchip: Add pcie port initialized flag

rk_pcie_port_initialized can be used to check if rockchip pcie port
initialization has been done (either successfully or failed). This
is needed for synchronization Rockpro64 sdio0 driver loading which
seems to make pcie training unstable if done too early.

Documentation/kernel-parameters.txt

@@ -3506,6 +3506,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	rhash_entries=	[KNL,NET]
 			Set number of hash buckets for route cache
 
+	rkdwmmc_defer_time=
+			Minimum time in ms to wait for Rockchip pcie port to get initialized
+			and to defer Rockchip dw_mmc probe. This is a workaround for
+			Rockpro64 sdio0 and pcie conflict. Only enabled with
+			CONFIG_PCIE_ROCKCHIP.
+			Default value is 2000.
+
 	ro		[KNL] Mount root device read-only on boot
 
 	rockchip.usb_uart

arch/arm64/boot/dts/rockchip/rk3399-rockpro64.dts

@@ -778,7 +778,8 @@
 	pinctrl-names = "default";
 	pinctrl-0 = <&sdio0_bus4 &sdio0_cmd &sdio0_clk>;
 	sd-uhs-sdr104;
-	status = "disabled";
+	status = "okay";
+	defer_pcie = <2000>;
 };
 
 &sdhci {

drivers/mmc/host/dw_mmc-rockchip.c

@@ -6,7 +6,7 @@
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  */
-
+#include <linux/ktime.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/clk.h>
@@ -202,10 +202,16 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
 	return ret;
 }
 
+#ifdef CONFIG_PCIE_ROCKCHIP
+extern bool rk_pcie_port_initialized;
+static s64 defer_start = 0, elapsed = 0;
+#endif
+
 static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
 {
 	struct device_node *np = host->dev->of_node;
 	struct dw_mci_rockchip_priv_data *priv;
+	int defer_pcie;
 
 	priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -223,6 +229,26 @@ static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
 	if (IS_ERR(priv->sample_clk))
 		dev_dbg(host->dev, "ciu_sample not available\n");
 
+#ifdef CONFIG_PCIE_ROCKCHIP
+	if (of_property_read_u32(np, "defer_pcie", &defer_pcie))
+		defer_pcie = 0;
+
+	if (defer_pcie > 0) {
+		if (!rk_pcie_port_initialized) {
+			if (defer_start == 0)
+				defer_start = ktime_to_ms(ktime_get());
+			elapsed = ktime_to_ms(ktime_get()) - defer_start;
+			if (elapsed <= defer_pcie) {
+				dev_info(host->dev, "deferring for a max of %dms while pcie port initializes. Waited %lldms so far.\n", defer_pcie, elapsed);
+				return -EPROBE_DEFER;
+			} else
+				dev_info(host->dev, "probe defer timed out waiting for pcie init, continuing...\n");
+		} else {
+			dev_info(host->dev, "detected pcie initialized, continuing...\n");
+		}
+	}
+#endif
+
 	host->priv = priv;
 
 	return 0;

drivers/mmc/host/dw_mmc.c

@@ -3182,6 +3182,13 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
 	if (!pdata)
 		return ERR_PTR(-ENOMEM);
 
+	/* find reset controller when exist */
+	pdata->rstc = devm_reset_control_get_optional(dev, NULL);
+	if (IS_ERR(pdata->rstc)) {
+		if (PTR_ERR(pdata->rstc) == -EPROBE_DEFER)
+			return ERR_PTR(-EPROBE_DEFER);
+	}
+
 	/* find out number of slots supported */
 	if (of_property_read_u32(dev->of_node, "num-slots",
 				&pdata->num_slots)) {
@@ -3262,7 +3269,9 @@ int dw_mci_probe(struct dw_mci *host)
 
 	if (!host->pdata) {
 		host->pdata = dw_mci_parse_dt(host);
-		if (IS_ERR(host->pdata)) {
+		if (PTR_ERR(host->pdata) == -EPROBE_DEFER) {
+			return -EPROBE_DEFER;
+		} else if (IS_ERR(host->pdata)) {
 			dev_err(host->dev, "platform data not available\n");
 			return -EINVAL;
 		}
@@ -3331,6 +3340,12 @@ int dw_mci_probe(struct dw_mci *host)
 		}
 	}
 
+	if (!IS_ERR(host->pdata->rstc)) {
+		reset_control_assert(host->pdata->rstc);
+		usleep_range(10, 50);
+		reset_control_deassert(host->pdata->rstc);
+	}
+
 	setup_timer(&host->cmd11_timer,
 		    dw_mci_cmd11_timer, (unsigned long)host);
 
@@ -3484,6 +3499,9 @@ int dw_mci_probe(struct dw_mci *host)
 	if (host->use_dma && host->dma_ops->exit)
 		host->dma_ops->exit(host);
 
+	if (!IS_ERR(host->pdata->rstc))
+		reset_control_assert(host->pdata->rstc);
+
 err_clk_ciu:
 	if (!IS_ERR(host->ciu_clk))
 		clk_disable_unprepare(host->ciu_clk);
@@ -3516,6 +3534,9 @@ void dw_mci_remove(struct dw_mci *host)
 	if (host->use_dma && host->dma_ops->exit)
 		host->dma_ops->exit(host);
 
+	if (!IS_ERR(host->pdata->rstc))
+		reset_control_assert(host->pdata->rstc);
+
 	if (!IS_ERR(host->ciu_clk))
 		clk_disable_unprepare(host->ciu_clk);
 

drivers/pci/host/pcie-rockchip.c

@@ -1277,6 +1277,9 @@ static int __maybe_unused rockchip_pcie_resume_noirq(struct device *dev)
 	return 0;
 }
 
+bool rk_pcie_port_initialized = false;
+EXPORT_SYMBOL(rk_pcie_port_initialized);
+
 static int rockchip_pcie_probe(struct platform_device *pdev)
 {
 	struct rockchip_pcie *rockchip;
@@ -1405,6 +1408,7 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 		pcie_bus_configure_settings(child);
 
 	pci_bus_add_devices(bus);
+	rk_pcie_port_initialized = true;
 	return err;
 
 err_free_res:
@@ -1425,6 +1429,7 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 err_aclk_perf_pcie:
 	clk_disable_unprepare(rockchip->aclk_pcie);
 err_aclk_pcie:
+	rk_pcie_port_initialized = true;
 	return err;
 }
 

include/linux/mmc/dw_mmc.h

@@ -17,6 +17,7 @@
 #include <linux/scatterlist.h>
 #include <linux/mmc/core.h>
 #include <linux/dmaengine.h>
+#include <linux/reset.h>
 
 #define MAX_MCI_SLOTS	2
 
@@ -280,6 +281,7 @@ struct dw_mci_board {
 	/* delay in mS before detecting cards after interrupt */
 	u32 detect_delay_ms;
 
+	struct reset_control *rstc;
 	struct dw_mci_dma_ops *dma_ops;
 	struct dma_pdata *data;
 };