usb: ehci: add workaround for chipidea PORTSC.PEC bug

Some NXP processor using chipidea IP has a bug when frame babble is
detected.

As per 4.15.1.1.1 Serial Bus Babble:
  A babble condition also exists if IN transaction is in progress at
High-speed SOF2 point. This is called frame babble. The host controller
must disable the port to which the frame babble is detected.

The USB controller has disabled the port (PE cleared) and has asserted
USBERRINT when frame babble is detected, but PEC is not asserted.
Therefore, the SW isn't aware that port has been disabled. Then the
SW keeps sending packets to this port, but all of the transfers will
fail.

This workaround will firstly assert PCD by SW when USBERRINT is detected
and then judge whether port change has really occurred or not by polling
roothub status. Because the PEC doesn't get asserted in our case, this
patch will also assert it by SW when specific conditions are satisfied.

Signed-off-by: Xu Yang <[email protected]>
Acked-by: Peter Chen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Xu Yang

drivers/usb/host/ehci-hcd.c

@@ -755,10 +755,14 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
 
 	/* normal [4.15.1.2] or error [4.15.1.1] completion */
 	if (likely ((status & (STS_INT|STS_ERR)) != 0)) {
-		if (likely ((status & STS_ERR) == 0))
+		if (likely ((status & STS_ERR) == 0)) {
 			INCR(ehci->stats.normal);
-		else
+		} else {
+			/* Force to check port status */
+			if (ehci->has_ci_pec_bug)
+				status |= STS_PCD;
 			INCR(ehci->stats.error);
+		}
 		bh = 1;
 	}
 

drivers/usb/host/ehci-hub.c

@@ -674,7 +674,8 @@ ehci_hub_status_data (struct usb_hcd *hcd, char *buf)
 
 		if ((temp & mask) != 0 || test_bit(i, &ehci->port_c_suspend)
 				|| (ehci->reset_done[i] && time_after_eq(
-					jiffies, ehci->reset_done[i]))) {
+					jiffies, ehci->reset_done[i]))
+				|| ehci_has_ci_pec_bug(ehci, temp)) {
 			if (i < 7)
 			    buf [0] |= 1 << (i + 1);
 			else
@@ -875,6 +876,13 @@ int ehci_hub_control(
 		if (temp & PORT_PEC)
 			status |= USB_PORT_STAT_C_ENABLE << 16;
 
+		if (ehci_has_ci_pec_bug(ehci, temp)) {
+			status |= USB_PORT_STAT_C_ENABLE << 16;
+			ehci_info(ehci,
+				"PE is cleared by HW port:%d PORTSC:%08x\n",
+				wIndex + 1, temp);
+		}
+
 		if ((temp & PORT_OCC) && (!ignore_oc && !ehci->spurious_oc)){
 			status |= USB_PORT_STAT_C_OVERCURRENT << 16;
 

drivers/usb/host/ehci.h

@@ -207,6 +207,7 @@ struct ehci_hcd {			/* one per controller */
 	unsigned		has_fsl_port_bug:1; /* FreeScale */
 	unsigned		has_fsl_hs_errata:1;	/* Freescale HS quirk */
 	unsigned		has_fsl_susp_errata:1;	/* NXP SUSP quirk */
+	unsigned		has_ci_pec_bug:1;	/* ChipIdea PEC bug */
 	unsigned		big_endian_mmio:1;
 	unsigned		big_endian_desc:1;
 	unsigned		big_endian_capbase:1;
@@ -707,6 +708,15 @@ ehci_port_speed(struct ehci_hcd *ehci, unsigned int portsc)
  */
 #define ehci_has_fsl_susp_errata(e)	((e)->has_fsl_susp_errata)
 
+/*
+ * Some Freescale/NXP processors using ChipIdea IP have a bug in which
+ * disabling the port (PE is cleared) does not cause PEC to be asserted
+ * when frame babble is detected.
+ */
+#define ehci_has_ci_pec_bug(e, portsc) \
+	((e)->has_ci_pec_bug && ((e)->command & CMD_PSE) \
+	 && !(portsc & PORT_PEC) && !(portsc & PORT_PE))
+
 /*
  * While most USB host controllers implement their registers in
  * little-endian format, a minority (celleb companion chip) implement