usb: cdns3: Enable workaround for USB2.0 PHY Rx compliance test PHY lockup

USB2.0 PHY hangs in Rx Compliance test when the incoming packet
amplitude is varied below and above the Squelch Level of
Receiver during the active packet multiple times.

Version 1 of the controller allows PHY to be reset when RX fail condition
is detected to work around the above issue. This feature is
disabled by default and needs to be enabled using a bit from
the newly added PHYRST_CFG register. This patch enables the workaround.

There is no way to know controller version before device controller
is started and the workaround needs to be applied for both host and
device modes, so we rely on a DT property do decide when to
apply the workaround.

Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/usb/cdns3/drd.c b/drivers/usb/cdns3/drd.c
index 5f2685cadf5e..fcd295f566b2 100644
--- a/drivers/usb/cdns3/drd.c
+++ b/drivers/usb/cdns3/drd.c
@@ -42,6 +42,18 @@ int cdns3_set_mode(struct cdns3 *cdns, enum usb_dr_mode mode)
 			reg = readl(&cdns->otg_v1_regs->override);
 			reg |= OVERRIDE_IDPULLUP;
 			writel(reg, &cdns->otg_v1_regs->override);
+
+			/*
+			 * Enable work around feature built into the
+			 * controller to address issue with RX Sensitivity
+			 * est (EL_17) for USB2 PHY. The issue only occures
+			 * for 0x0002450D controller version.
+			 */
+			if (cdns->phyrst_a_enable) {
+				reg = readl(&cdns->otg_v1_regs->phyrst_cfg);
+				reg |= PHYRST_CFG_PHYRST_A_ENABLE;
+				writel(reg, &cdns->otg_v1_regs->phyrst_cfg);
+			}
 		} else {
 			reg = readl(&cdns->otg_v0_regs->ctrl1);
 			reg |= OVERRIDE_IDPULLUP_V0;