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Commit 950c769d authored by Vamsi Krishna Samavedam's avatar Vamsi Krishna Samavedam
Browse files

usb: dwc3: Improve lfps handshake interop by reducing u3 exit time 



SNPS star 9001276244:LFPS Handshake Interoperability Issues suggests
to reduce U3 exit handshake timer to from 8us to 300ns to increase
interoperability with hosts/devices which supports USB 3.1 gen2
speeds.

Change-Id: I68c6f5f8a09337c5c3c70c2f0b6940efcba0dab8
Signed-off-by: default avatarVamsi Krishna Samavedam <vskrishn@codeaurora.org>
parent eeebcdff

drivers/usb/dwc3/core.h

+5 −0
Original line number Diff line number Diff line
@@ -160,6 +160,11 @@ 
#define DWC3_OSTS		0xcc10



/* DWC 3.1 Link Registers */

#define DWC31_LINK_LU3LFPSRXTIM(n)	(0xd010 + ((n) * 0x80))

#define GEN2_U3_EXIT_RSP_RX_CLK(n)	((n) << 16)

#define GEN2_U3_EXIT_RSP_RX_CLK_MASK	GEN2_U3_EXIT_RSP_RX_CLK(0xff)

#define GEN1_U3_EXIT_RSP_RX_CLK(n)	(n)

#define GEN1_U3_EXIT_RSP_RX_CLK_MASK	GEN1_U3_EXIT_RSP_RX_CLK(0xff)

#define DWC31_LINK_GDBGLTSSM	0xd050



/* Bit fields */

drivers/usb/dwc3/dwc3-msm.c

+31 −0
Original line number Diff line number Diff line
@@ -3686,6 +3686,21 @@ static int dwc3_otg_start_host(struct dwc3_msm *mdwc, int on) 
		mdwc->in_host_mode = true;

		dwc3_usb3_phy_suspend(dwc, true);



		/* Reduce the U3 exit handshake timer from 8us to approximately

		 * 300ns to avoid lfps handshake interoperability issues

		 */

		if (dwc->revision == DWC3_USB31_REVISION_170A) {

			dwc3_msm_write_reg_field(mdwc->base,

					DWC31_LINK_LU3LFPSRXTIM(0),

					GEN2_U3_EXIT_RSP_RX_CLK_MASK, 6);

			dwc3_msm_write_reg_field(mdwc->base,

					DWC31_LINK_LU3LFPSRXTIM(0),

					GEN1_U3_EXIT_RSP_RX_CLK_MASK, 5);

			dev_dbg(mdwc->dev, "LU3:%08x\n",

				dwc3_msm_read_reg(mdwc->base,

					DWC31_LINK_LU3LFPSRXTIM(0)));

		}



		/* xHCI should have incremented child count as necessary */

		dbg_event(0xFF, "StrtHost psync",

			atomic_read(&mdwc->dev->power.usage_count));
@@ -3792,6 +3807,22 @@ static int dwc3_otg_start_peripheral(struct dwc3_msm *mdwc, int on) 
		dwc3_msm_block_reset(mdwc, false);

		dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_DEVICE);

		mdwc->in_device_mode = true;



		/* Reduce the U3 exit handshake timer from 8us to approximately

		 * 300ns to avoid lfps handshake interoperability issues

		 */

		if (dwc->revision == DWC3_USB31_REVISION_170A) {

			dwc3_msm_write_reg_field(mdwc->base,

					DWC31_LINK_LU3LFPSRXTIM(0),

					GEN2_U3_EXIT_RSP_RX_CLK_MASK, 6);

			dwc3_msm_write_reg_field(mdwc->base,

					DWC31_LINK_LU3LFPSRXTIM(0),

					GEN1_U3_EXIT_RSP_RX_CLK_MASK, 5);

			dev_dbg(mdwc->dev, "LU3:%08x\n",

				dwc3_msm_read_reg(mdwc->base,

					DWC31_LINK_LU3LFPSRXTIM(0)));

		}



		usb_gadget_vbus_connect(&dwc->gadget);

#ifdef CONFIG_SMP

		mdwc->pm_qos_req_dma.type = PM_QOS_REQ_AFFINE_IRQ;