usb: dwc3: enable CCI support for AMD-xilinx DWC3 controller

The GSBUSCFG0 register bits [31:16] are used to configure the cache type
settings of the descriptor and data write/read transfers (Cacheable,
Bufferable/Posted). When CCI is enabled in the design, DWC3 core GSBUSCFG0
cache bits must be updated to support CCI enabled transfers in USB.

To program GSBUSCFG0 cache bits create a software node property
in AMD-xilinx dwc3 glue driver and pass it to dwc3 core. The core
then reads this property value and configures it in dwc3_core_init()
sequence.

Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/1720548651-726412-1-git-send-email-radhey.shyam.pandey@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Radhey Shyam Pandey

drivers/usb/dwc3/core.c

@@ -604,6 +604,18 @@ static void dwc3_cache_hwparams(struct dwc3 *dwc)
 		parms->hwparams9 = dwc3_readl(dwc->regs, DWC3_GHWPARAMS9);
 }
 
+static void dwc3_config_soc_bus(struct dwc3 *dwc)
+{
+	if (dwc->gsbuscfg0_reqinfo != DWC3_GSBUSCFG0_REQINFO_UNSPECIFIED) {
+		u32 reg;
+
+		reg = dwc3_readl(dwc->regs, DWC3_GSBUSCFG0);
+		reg &= ~DWC3_GSBUSCFG0_REQINFO(~0);
+		reg |= DWC3_GSBUSCFG0_REQINFO(dwc->gsbuscfg0_reqinfo);
+		dwc3_writel(dwc->regs, DWC3_GSBUSCFG0, reg);
+	}
+}
+
 static int dwc3_core_ulpi_init(struct dwc3 *dwc)
 {
 	int intf;
@@ -1343,6 +1355,8 @@ static int dwc3_core_init(struct dwc3 *dwc)
 
 	dwc3_set_incr_burst_type(dwc);
 
+	dwc3_config_soc_bus(dwc);
+
 	ret = dwc3_phy_power_on(dwc);
 	if (ret)
 		goto err_exit_phy;
@@ -1581,6 +1595,27 @@ static void dwc3_core_exit_mode(struct dwc3 *dwc)
 	dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_DEVICE);
 }
 
+static void dwc3_get_software_properties(struct dwc3 *dwc)
+{
+	struct device *tmpdev;
+	u16 gsbuscfg0_reqinfo;
+	int ret;
+
+	dwc->gsbuscfg0_reqinfo = DWC3_GSBUSCFG0_REQINFO_UNSPECIFIED;
+
+	/*
+	 * Iterate over all parent nodes for finding swnode properties
+	 * and non-DT (non-ABI) properties.
+	 */
+	for (tmpdev = dwc->dev; tmpdev; tmpdev = tmpdev->parent) {
+		ret = device_property_read_u16(tmpdev,
+					       "snps,gsbuscfg0-reqinfo",
+					       &gsbuscfg0_reqinfo);
+		if (!ret)
+			dwc->gsbuscfg0_reqinfo = gsbuscfg0_reqinfo;
+	}
+}
+
 static void dwc3_get_properties(struct dwc3 *dwc)
 {
 	struct device		*dev = dwc->dev;
@@ -2095,6 +2130,8 @@ static int dwc3_probe(struct platform_device *pdev)
 
 	dwc3_get_properties(dwc);
 
+	dwc3_get_software_properties(dwc);
+
 	dwc->reset = devm_reset_control_array_get_optional_shared(dev);
 	if (IS_ERR(dwc->reset)) {
 		ret = PTR_ERR(dwc->reset);

drivers/usb/dwc3/core.h

@@ -194,6 +194,10 @@
 #define DWC3_GSBUSCFG0_INCRBRSTENA	(1 << 0) /* undefined length enable */
 #define DWC3_GSBUSCFG0_INCRBRST_MASK	0xff
 
+/* Global SoC Bus Configuration Register: AHB-prot/AXI-cache/OCP-ReqInfo */
+#define DWC3_GSBUSCFG0_REQINFO(n)	(((n) & 0xffff) << 16)
+#define DWC3_GSBUSCFG0_REQINFO_UNSPECIFIED	0xffffffff
+
 /* Global Debug LSP MUX Select */
 #define DWC3_GDBGLSPMUX_ENDBC		BIT(15)	/* Host only */
 #define DWC3_GDBGLSPMUX_HOSTSELECT(n)	((n) & 0x3fff)
@@ -1153,6 +1157,9 @@ struct dwc3_scratchpad_array {
  * @num_ep_resized: carries the current number endpoints which have had its tx
  *		    fifo resized.
  * @debug_root: root debugfs directory for this device to put its files in.
+ * @gsbuscfg0_reqinfo: store GSBUSCFG0.DATRDREQINFO, DESRDREQINFO,
+ *		       DATWRREQINFO, and DESWRREQINFO value passed from
+ *		       glue driver.
  */
 struct dwc3 {
 	struct work_struct	drd_work;
@@ -1380,6 +1387,7 @@ struct dwc3 {
 	int			last_fifo_depth;
 	int			num_ep_resized;
 	struct dentry		*debug_root;
+	u32			gsbuscfg0_reqinfo;
 };
 
 #define INCRX_BURST_MODE 0

drivers/usb/dwc3/dwc3-xilinx.c

@@ -246,6 +246,31 @@ static const struct of_device_id dwc3_xlnx_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, dwc3_xlnx_of_match);
 
+static int dwc3_set_swnode(struct device *dev)
+{
+	struct device_node *np = dev->of_node, *dwc3_np;
+	struct property_entry props[2];
+	int prop_idx = 0, ret = 0;
+
+	dwc3_np = of_get_compatible_child(np, "snps,dwc3");
+	if (!dwc3_np) {
+		ret = -ENODEV;
+		dev_err(dev, "failed to find dwc3 core child\n");
+		return ret;
+	}
+
+	memset(props, 0, sizeof(struct property_entry) * ARRAY_SIZE(props));
+	if (of_dma_is_coherent(dwc3_np))
+		props[prop_idx++] = PROPERTY_ENTRY_U16("snps,gsbuscfg0-reqinfo",
+						       0xffff);
+	of_node_put(dwc3_np);
+
+	if (prop_idx)
+		ret = device_create_managed_software_node(dev, props, NULL);
+
+	return ret;
+}
+
 static int dwc3_xlnx_probe(struct platform_device *pdev)
 {
 	struct dwc3_xlnx		*priv_data;
@@ -288,6 +313,10 @@ static int dwc3_xlnx_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_clk_put;
 
+	ret = dwc3_set_swnode(dev);
+	if (ret)
+		goto err_clk_put;
+
 	ret = of_platform_populate(np, NULL, NULL, dev);
 	if (ret)
 		goto err_clk_put;