[PATCH v2 6/9] usb: dwc3: Enable undefined length INCR burst type

[Michael Walle]

[backport from linux commit d9612c2f0449e24983a8b689603210486a930c90]

Enable the undefined length INCR burst type and set INCRx.
Different platform may has the different burst size type.
In order to get best performance, we need to tune the burst
size to one special value, instead of the default value.

Signed-off-by: Michael Walle <michael at walle.cc>
---
 drivers/usb/dwc3/core.c | 69 +++++++++++++++++++++++++++++++++++++++++
 drivers/usb/dwc3/core.h | 16 ++++++++++
 2 files changed, 85 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 4fb6b59d50..ce1c0e88c2 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -462,6 +462,53 @@ static void dwc3_phy_setup(struct dwc3 *dwc)
 	mdelay(100);
 }
 
+/* set global incr burst type configuration registers */
+static void dwc3_set_incr_burst_type(struct dwc3 *dwc)
+{
+	struct udevice *dev = dwc->dev;
+	u32 cfg;
+
+	if (!dwc->incrx_size)
+		return;
+
+	cfg = dwc3_readl(dwc->regs, DWC3_GSBUSCFG0);
+
+	/* Enable Undefined Length INCR Burst and Enable INCRx Burst */
+	cfg &= ~DWC3_GSBUSCFG0_INCRBRST_MASK;
+	if (dwc->incrx_mode)
+		cfg |= DWC3_GSBUSCFG0_INCRBRSTENA;
+	switch (dwc->incrx_size) {
+	case 256:
+		cfg |= DWC3_GSBUSCFG0_INCR256BRSTENA;
+		break;
+	case 128:
+		cfg |= DWC3_GSBUSCFG0_INCR128BRSTENA;
+		break;
+	case 64:
+		cfg |= DWC3_GSBUSCFG0_INCR64BRSTENA;
+		break;
+	case 32:
+		cfg |= DWC3_GSBUSCFG0_INCR32BRSTENA;
+		break;
+	case 16:
+		cfg |= DWC3_GSBUSCFG0_INCR16BRSTENA;
+		break;
+	case 8:
+		cfg |= DWC3_GSBUSCFG0_INCR8BRSTENA;
+		break;
+	case 4:
+		cfg |= DWC3_GSBUSCFG0_INCR4BRSTENA;
+		break;
+	case 1:
+		break;
+	default:
+		dev_err(dev, "Invalid property\n");
+		break;
+	}
+
+	dwc3_writel(dwc->regs, DWC3_GSBUSCFG0, cfg);
+}
+
 /**
  * dwc3_core_init - Low-level initialization of DWC3 Core
  * @dwc: Pointer to our controller context structure
@@ -593,6 +640,8 @@ static int dwc3_core_init(struct dwc3 *dwc)
 	/* Adjust Frame Length */
 	dwc3_frame_length_adjustment(dwc, dwc->fladj);
 
+	dwc3_set_incr_burst_type(dwc);
+
 	return 0;
 
 err1:
@@ -916,6 +965,8 @@ void dwc3_of_parse(struct dwc3 *dwc)
 	u8 lpm_nyet_threshold;
 	u8 tx_de_emphasis;
 	u8 hird_threshold;
+	u32 val;
+	int i;
 
 	/* default to highest possible threshold */
 	lpm_nyet_threshold = 0xff;
@@ -984,6 +1035,24 @@ void dwc3_of_parse(struct dwc3 *dwc)
 		| (dwc->is_utmi_l1_suspend << 4);
 
 	dev_read_u32(dev, "snps,quirk-frame-length-adjustment", &dwc->fladj);
+
+	/*
+	 * Handle property "snps,incr-burst-type-adjustment".
+	 * Get the number of value from this property:
+	 * result <= 0, means this property is not supported.
+	 * result = 1, means INCRx burst mode supported.
+	 * result > 1, means undefined length burst mode supported.
+	 */
+	dwc->incrx_mode = INCRX_BURST_MODE;
+	dwc->incrx_size = 0;
+	for (i = 0; i < 8; i++) {
+		if (dev_read_u32_index(dev, "snps,incr-burst-type-adjustment",
+				       i, &val))
+			break;
+
+		dwc->incrx_mode = INCRX_UNDEF_LENGTH_BURST_MODE;
+		dwc->incrx_size = max(dwc->incrx_size, val);
+	}
 }
 
 int dwc3_init(struct dwc3 *dwc)
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 62e4df74fa..d7cce3a861 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -139,6 +139,17 @@
 
 /* Bit fields */
 
+/* Global SoC Bus Configuration INCRx Register 0 */
+#define DWC3_GSBUSCFG0_INCR256BRSTENA	(1 << 7) /* INCR256 burst */
+#define DWC3_GSBUSCFG0_INCR128BRSTENA	(1 << 6) /* INCR128 burst */
+#define DWC3_GSBUSCFG0_INCR64BRSTENA	(1 << 5) /* INCR64 burst */
+#define DWC3_GSBUSCFG0_INCR32BRSTENA	(1 << 4) /* INCR32 burst */
+#define DWC3_GSBUSCFG0_INCR16BRSTENA	(1 << 3) /* INCR16 burst */
+#define DWC3_GSBUSCFG0_INCR8BRSTENA	(1 << 2) /* INCR8 burst */
+#define DWC3_GSBUSCFG0_INCR4BRSTENA	(1 << 1) /* INCR4 burst */
+#define DWC3_GSBUSCFG0_INCRBRSTENA	(1 << 0) /* undefined length enable */
+#define DWC3_GSBUSCFG0_INCRBRST_MASK	0xff
+
 /* Global Configuration Register */
 #define DWC3_GCTL_PWRDNSCALE(n)	((n) << 19)
 #define DWC3_GCTL_U2RSTECN	(1 << 16)
@@ -818,6 +829,8 @@ struct dwc3 {
 	u8			lpm_nyet_threshold;
 	u8			hird_threshold;
 	u32			fladj;
+	u8			incrx_mode;
+	u32			incrx_size;
 
 	unsigned		delayed_status:1;
 	unsigned		ep0_bounced:1;
@@ -855,6 +868,9 @@ struct dwc3 {
 	struct list_head        list;
 };
 
+#define INCRX_BURST_MODE 0
+#define INCRX_UNDEF_LENGTH_BURST_MODE 1
+
 /* -------------------------------------------------------------------------- */
 
 /* -------------------------------------------------------------------------- */
-- 
2.30.2