[PATCH v3] fsl-layerscape: enable dwc3 snooping feature

[Ran Wang]

Configure DWC3’s cache type to ‘cacheable’ for better
performance. Actually related register definition and values are SoC
specific, which means this setting is only applicable to Layerscape SoC,
not generic for all platforms which have integrated DWC3 IP.

Signed-off-by: Ran Wang <ran.wang_1 at nxp.com>
---
Change in v3:
 - Add 'if (IS_ENABLED(CONFIG_DM))' to fix compile issue (ls2080a_simu_defconfig)

Change in v2:
 - Move enable_dwc3_snooping() implementation to fix compile issue for ls1043a.

 arch/arm/cpu/armv8/fsl-layerscape/soc.c | 37 +++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/arch/arm/cpu/armv8/fsl-layerscape/soc.c b/arch/arm/cpu/armv8/fsl-layerscape/soc.c
index fde893e..5254cdf 100644
--- a/arch/arm/cpu/armv8/fsl-layerscape/soc.c
+++ b/arch/arm/cpu/armv8/fsl-layerscape/soc.c
@@ -36,6 +36,8 @@
 #ifdef CONFIG_TFABOOT
 #include <env_internal.h>
 #endif
+#include <dm.h>
+#include <linux/err.h>
 #if defined(CONFIG_TFABOOT) || defined(CONFIG_GIC_V3_ITS)
 DECLARE_GLOBAL_DATA_PTR;
 #endif
@@ -897,6 +899,38 @@ __weak int fsl_board_late_init(void)
 	return 0;
 }
 
+#define DWC3_GSBUSCFG0			0xc100
+#define DWC3_GSBUSCFG0_CACHETYPE_SHIFT	16
+#define DWC3_GSBUSCFG0_CACHETYPE(n)        (((n) & 0xffff)            \
+	<< DWC3_GSBUSCFG0_CACHETYPE_SHIFT)
+
+void enable_dwc3_snooping(void)
+{
+	int ret;
+	u32 val;
+	struct udevice *bus;
+	struct uclass *uc;
+	fdt_addr_t dwc3_base;
+
+	ret = uclass_get(UCLASS_USB, &uc);
+	if (ret)
+		return;
+
+	uclass_foreach_dev(bus, uc) {
+		if (!strcmp(bus->driver->of_match->compatible, "fsl,layerscape-dwc3")) {
+			dwc3_base = devfdt_get_addr(bus);
+			if (dwc3_base == FDT_ADDR_T_NONE) {
+				dev_err(bus, "dwc3 regs missing\n");
+				continue;
+			}
+			val = in_le32(dwc3_base + DWC3_GSBUSCFG0);
+			val &= ~DWC3_GSBUSCFG0_CACHETYPE(~0);
+			val |= DWC3_GSBUSCFG0_CACHETYPE(0x2222);
+			writel(val, dwc3_base + DWC3_GSBUSCFG0);
+		}
+	}
+}
+
 int board_late_init(void)
 {
 #ifdef CONFIG_CHAIN_OF_TRUST
@@ -934,6 +968,9 @@ int board_late_init(void)
 	fspi_ahb_init();
 #endif
 
+	if (IS_ENABLED(CONFIG_DM))
+		enable_dwc3_snooping();
+
 	return fsl_board_late_init();
 }
 #endif
-- 
2.7.4