usb: dwc2: host: enable descriptor dma for fs devices

As descriptor dma mode does not support split transfers, it can't be
enabled for high speed devices. Add a core parameter to enable it for
full speed devices.

Ensure frame list and descriptor list are correctly freed during
disconnect.
Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
Signed-off-by: Gregory Herrero <gregory.herrero@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc2/core.c

@@ -2485,6 +2485,29 @@ void dwc2_set_param_dma_desc_enable(struct dwc2_hsotg *hsotg, int val)
 	hsotg->core_params->dma_desc_enable = val;
 }
 
+void dwc2_set_param_dma_desc_fs_enable(struct dwc2_hsotg *hsotg, int val)
+{
+	int valid = 1;
+
+	if (val > 0 && (hsotg->core_params->dma_enable <= 0 ||
+			!hsotg->hw_params.dma_desc_enable))
+		valid = 0;
+	if (val < 0)
+		valid = 0;
+
+	if (!valid) {
+		if (val >= 0)
+			dev_err(hsotg->dev,
+				"%d invalid for dma_desc_fs_enable parameter. Check HW configuration.\n",
+				val);
+		val = (hsotg->core_params->dma_enable > 0 &&
+			hsotg->hw_params.dma_desc_enable);
+	}
+
+	hsotg->core_params->dma_desc_fs_enable = val;
+	dev_dbg(hsotg->dev, "Setting dma_desc_fs_enable to %d\n", val);
+}
+
 void dwc2_set_param_host_support_fs_ls_low_power(struct dwc2_hsotg *hsotg,
 						 int val)
 {
@@ -3016,6 +3039,7 @@ void dwc2_set_parameters(struct dwc2_hsotg *hsotg,
 	dwc2_set_param_otg_cap(hsotg, params->otg_cap);
 	dwc2_set_param_dma_enable(hsotg, params->dma_enable);
 	dwc2_set_param_dma_desc_enable(hsotg, params->dma_desc_enable);
+	dwc2_set_param_dma_desc_fs_enable(hsotg, params->dma_desc_fs_enable);
 	dwc2_set_param_host_support_fs_ls_low_power(hsotg,
 			params->host_support_fs_ls_low_power);
 	dwc2_set_param_enable_dynamic_fifo(hsotg,

drivers/usb/dwc2/core.h

@@ -246,6 +246,13 @@ enum dwc2_ep0_state {
  *                      value for this if none is specified.
  *                       0 - Address DMA
  *                       1 - Descriptor DMA (default, if available)
+ * @dma_desc_fs_enable: When DMA mode is enabled, specifies whether to use
+ *                      address DMA mode or descriptor DMA mode for accessing
+ *                      the data FIFOs in Full Speed mode only. The driver
+ *                      will automatically detect the value for this if none is
+ *                      specified.
+ *                       0 - Address DMA
+ *                       1 - Descriptor DMA in FS (default, if available)
  * @speed:              Specifies the maximum speed of operation in host and
  *                      device mode. The actual speed depends on the speed of
  *                      the attached device and the value of phy_type.
@@ -375,6 +382,7 @@ struct dwc2_core_params {
 	int otg_ver;
 	int dma_enable;
 	int dma_desc_enable;
+	int dma_desc_fs_enable;
 	int speed;
 	int enable_dynamic_fifo;
 	int en_multiple_tx_fifo;
@@ -456,6 +464,7 @@ struct dwc2_hw_params {
 	unsigned op_mode:3;
 	unsigned arch:2;
 	unsigned dma_desc_enable:1;
+	unsigned dma_desc_fs_enable:1;
 	unsigned enable_dynamic_fifo:1;
 	unsigned en_multiple_tx_fifo:1;
 	unsigned host_rx_fifo_size:16;
@@ -770,6 +779,7 @@ struct dwc2_hsotg {
 	u16 frame_number;
 	u16 periodic_qh_count;
 	bool bus_suspended;
+	bool new_connection;
 
 #ifdef CONFIG_USB_DWC2_TRACK_MISSED_SOFS
 #define FRAME_NUM_ARRAY_SIZE 1000
@@ -941,6 +951,16 @@ extern void dwc2_set_param_dma_enable(struct dwc2_hsotg *hsotg, int val);
  */
 extern void dwc2_set_param_dma_desc_enable(struct dwc2_hsotg *hsotg, int val);
 
+/*
+ * When DMA mode is enabled specifies whether to use
+ * address DMA or DMA Descritor mode with full speed devices
+ * for accessing the data FIFOs in host mode.
+ * 0 - address DMA
+ * 1 - FS DMA Descriptor(default, if available)
+ */
+extern void dwc2_set_param_dma_desc_fs_enable(struct dwc2_hsotg *hsotg,
+					      int val);
+
 /*
  * Specifies the maximum speed of operation in host and device mode.
  * The actual speed depends on the speed of the attached device and

drivers/usb/dwc2/hcd.c

@@ -1734,6 +1734,28 @@ static int dwc2_hcd_hub_control(struct dwc2_hsotg *hsotg, u16 typereq,
 			port_status |= USB_PORT_STAT_TEST;
 		/* USB_PORT_FEAT_INDICATOR unsupported always 0 */
 
+		if (hsotg->core_params->dma_desc_fs_enable) {
+			/*
+			 * Enable descriptor DMA only if a full speed
+			 * device is connected.
+			 */
+			if (hsotg->new_connection &&
+			    ((port_status &
+			      (USB_PORT_STAT_CONNECTION |
+			       USB_PORT_STAT_HIGH_SPEED |
+			       USB_PORT_STAT_LOW_SPEED)) ==
+			       USB_PORT_STAT_CONNECTION)) {
+				u32 hcfg;
+
+				dev_info(hsotg->dev, "Enabling descriptor DMA mode\n");
+				hsotg->core_params->dma_desc_enable = 1;
+				hcfg = dwc2_readl(hsotg->regs + HCFG);
+				hcfg |= HCFG_DESCDMA;
+				dwc2_writel(hcfg, hsotg->regs + HCFG);
+				hsotg->new_connection = false;
+			}
+		}
+
 		dev_vdbg(hsotg->dev, "port_status=%08x\n", port_status);
 		*(__le32 *)buf = cpu_to_le32(port_status);
 		break;

drivers/usb/dwc2/hcd_intr.c

@@ -372,10 +372,21 @@ static void dwc2_port_intr(struct dwc2_hsotg *hsotg)
 			 "  --Port Interrupt HPRT0=0x%08x Port Enable Changed (now %d)--\n",
 			 hprt0, !!(hprt0 & HPRT0_ENA));
 		hprt0_modify |= HPRT0_ENACHG;
-		if (hprt0 & HPRT0_ENA)
+		if (hprt0 & HPRT0_ENA) {
+			hsotg->new_connection = true;
 			dwc2_hprt0_enable(hsotg, hprt0, &hprt0_modify);
-		else
+		} else {
 			hsotg->flags.b.port_enable_change = 1;
+			if (hsotg->core_params->dma_desc_fs_enable) {
+				u32 hcfg;
+
+				hsotg->core_params->dma_desc_enable = 0;
+				hsotg->new_connection = false;
+				hcfg = dwc2_readl(hsotg->regs + HCFG);
+				hcfg &= ~HCFG_DESCDMA;
+				dwc2_writel(hcfg, hsotg->regs + HCFG);
+			}
+		}
 	}
 
 	/* Overcurrent Change Interrupt */

drivers/usb/dwc2/hcd_queue.c

@@ -232,7 +232,7 @@ struct dwc2_qh *dwc2_hcd_qh_create(struct dwc2_hsotg *hsotg,
  */
 void dwc2_hcd_qh_free(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
 {
-	if (hsotg->core_params->dma_desc_enable > 0) {
+	if (qh->desc_list) {
 		dwc2_hcd_qh_free_ddma(hsotg, qh);
 	} else {
 		/* kfree(NULL) is safe */

drivers/usb/dwc2/platform.c

@@ -59,6 +59,7 @@ static const struct dwc2_core_params params_bcm2835 = {
 	.otg_ver			= 0,	/* 1.3 */
 	.dma_enable			= 1,
 	.dma_desc_enable		= 0,
+	.dma_desc_fs_enable		= 0,
 	.speed				= 0,	/* High Speed */
 	.enable_dynamic_fifo		= 1,
 	.en_multiple_tx_fifo		= 1,
@@ -89,6 +90,7 @@ static const struct dwc2_core_params params_rk3066 = {
 	.otg_ver			= -1,
 	.dma_enable			= -1,
 	.dma_desc_enable		= 0,
+	.dma_desc_fs_enable		= 0,
 	.speed				= -1,
 	.enable_dynamic_fifo		= 1,
 	.en_multiple_tx_fifo		= -1,
@@ -348,8 +350,10 @@ static int dwc2_driver_probe(struct platform_device *dev)
 		/*
 		 * Disable descriptor dma mode by default as the HW can support
 		 * it, but does not support it for SPLIT transactions.
+		 * Disable it for FS devices as well.
 		 */
 		defparams.dma_desc_enable = 0;
+		defparams.dma_desc_fs_enable = 0;
 	}
 
 	hsotg = devm_kzalloc(&dev->dev, sizeof(*hsotg), GFP_KERNEL);