linux-kernel - [PATCH] fsl/usb: Workarourd for USB erratum-A005697

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Message-ID: <1479979089-4715-1-git-send-email-jerry.huang@nxp.com>
Date:   Thu, 24 Nov 2016 17:18:09 +0800
From:   Changming Huang <jerry.huang@....com>
To:     <stern@...land.harvard.edu>, <gregkh@...uxfoundation.org>
CC:     <sriram.dash@....com>, <linux-usb@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <julia.lawall@...6.fr>,
        Changming Huang <jerry.huang@....com>,
        Ramneek Mehresh <ramneek.mehresh@....com>
Subject: [PATCH] fsl/usb: Workarourd for USB erratum-A005697

As per USB specification, in the Suspend state, the status bit does
not change until the port is suspended. However, there may be a delay
in suspending a port if there is a transaction currently in progress
on the bus.

In the USBDR controller, the PORTSCx[SUSP] bit changes immediately when
the application sets it and not when the port is actually suspended

Workaround for this issue involves waiting for a minimum of 10ms to
allow the controller to go into SUSPEND state before proceeding ahead

Signed-off-by: Changming Huang <jerry.huang@....com>
Signed-off-by: Ramneek Mehresh <ramneek.mehresh@....com>
---
 drivers/usb/host/ehci-fsl.c      |    3 +++
 drivers/usb/host/ehci-hub.c      |    2 ++
 drivers/usb/host/ehci.h          |    6 ++++++
 drivers/usb/host/fsl-mph-dr-of.c |    2 ++
 include/linux/fsl_devices.h      |    1 +
 5 files changed, 14 insertions(+)

diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
index 9f5ffb6..91701cc 100644
--- a/drivers/usb/host/ehci-fsl.c
+++ b/drivers/usb/host/ehci-fsl.c
@@ -286,6 +286,9 @@ static int ehci_fsl_usb_setup(struct ehci_hcd *ehci)
 	if (pdata->has_fsl_erratum_a005275 == 1)
 		ehci->has_fsl_hs_errata = 1;
 
+	if (pdata->has_fsl_erratum_a005697 == 1)
+		ehci->has_fsl_susp_errata = 1;
+
 	if ((pdata->operating_mode == FSL_USB2_DR_HOST) ||
 			(pdata->operating_mode == FSL_USB2_DR_OTG))
 		if (ehci_fsl_setup_phy(hcd, pdata->phy_mode, 0))
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 74f62d6..86d154e 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -305,6 +305,8 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
 						USB_PORT_STAT_HIGH_SPEED)
 				fs_idle_delay = true;
 			ehci_writel(ehci, t2, reg);
+			if (ehci_has_fsl_susp_errata(ehci))
+				mdelay(10);
 			changed = 1;
 		}
 	}
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index 3f3b74a..7706e4a 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -219,6 +219,7 @@ struct ehci_hcd {			/* one per controller */
 	unsigned		no_selective_suspend:1;
 	unsigned		has_fsl_port_bug:1; /* FreeScale */
 	unsigned		has_fsl_hs_errata:1;	/* Freescale HS quirk */
+	unsigned		has_fsl_susp_errata:1;	/*Freescale SUSP quirk*/
 	unsigned		big_endian_mmio:1;
 	unsigned		big_endian_desc:1;
 	unsigned		big_endian_capbase:1;
@@ -703,10 +704,15 @@ struct ehci_tt {
 #if defined(CONFIG_PPC_85xx)
 /* Some Freescale processors have an erratum (USB A-005275) in which
  * incoming packets get corrupted in HS mode
+ * Some Freescale processors have an erratum (USB A-005697) in which
+ * we need to wait for 10ms for bus to fo into suspend mode after
+ * setting SUSP bit
  */
 #define ehci_has_fsl_hs_errata(e)	((e)->has_fsl_hs_errata)
+#define ehci_has_fsl_susp_errata(e)	((e)->has_fsl_susp_errata)
 #else
 #define ehci_has_fsl_hs_errata(e)	(0)
+#define ehci_has_fsl_susp_errata(e)	(0)
 #endif
 
 /*
diff --git a/drivers/usb/host/fsl-mph-dr-of.c b/drivers/usb/host/fsl-mph-dr-of.c
index f07ccb2..e90ddb5 100644
--- a/drivers/usb/host/fsl-mph-dr-of.c
+++ b/drivers/usb/host/fsl-mph-dr-of.c
@@ -226,6 +226,8 @@ static int fsl_usb2_mph_dr_of_probe(struct platform_device *ofdev)
 		of_property_read_bool(np, "fsl,usb-erratum-a007792");
 	pdata->has_fsl_erratum_a005275 =
 		of_property_read_bool(np, "fsl,usb-erratum-a005275");
+	pdata->has_fsl_erratum_a005697 =
+		of_property_read_bool(np, "fsl,usb_erratum-a005697");
 
 	/*
 	 * Determine whether phy_clk_valid needs to be checked
diff --git a/include/linux/fsl_devices.h b/include/linux/fsl_devices.h
index f291291..60cef82 100644
--- a/include/linux/fsl_devices.h
+++ b/include/linux/fsl_devices.h
@@ -100,6 +100,7 @@ struct fsl_usb2_platform_data {
 	unsigned	already_suspended:1;
 	unsigned        has_fsl_erratum_a007792:1;
 	unsigned        has_fsl_erratum_a005275:1;
+	unsigned	has_fsl_erratum_a005697:1;
 	unsigned        check_phy_clk_valid:1;
 
 	/* register save area for suspend/resume */
-- 
1.7.9.5