From: Nikhil Badola <nikhil.badola@freescale.com>
To: <linux-kernel@vger.kernel.org>, <linux-usb@vger.kernel.org>
CC: <stern@rowland.harvard.edu>, <gregkh@linuxfoundation.org>,
        Nikhil Badola <nikhil.badola@freescale.com>,
        Ramneek Mehresh <ramneek.mehresh@freescale.com>
Subject: [PATCH] drivers: usb: fsl: Workaround for USB erratum-A005275
Date: Fri, 31 Jul 2015 12:06:20 +0530
Message-ID: <1438324580-25308-1-git-send-email-nikhil.badola@freescale.com>
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Incoming packets in high speed are randomly corrupted by h/w
resulting in multiple errors. This workaround makes FS as
default mode in all affected socs by disabling HS chirp
signalling.This errata does not affect FS and LS mode.

Forces all HS devices to connect in FS mode for all socs
affected by this erratum:
P3041 and P2041 rev 1.0 and 1.1
P5020 and P5010 rev 1.0 and 2.0
P5040, P1010 and T4240 rev 1.0

Signed-off-by: Ramneek Mehresh <ramneek.mehresh@freescale.com>
Signed-off-by: Nikhil Badola <nikhil.badola@freescale.com>
---
 drivers/usb/host/ehci-fsl.c      |  4 ++++
 drivers/usb/host/ehci-hub.c      |  7 +++++++
 drivers/usb/host/ehci.h          | 12 ++++++++++++
 drivers/usb/host/fsl-mph-dr-of.c |  4 ++++
 include/linux/fsl_devices.h      |  1 +
 5 files changed, 28 insertions(+)

diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
index 202dafb..3b6eb21 100644
--- a/drivers/usb/host/ehci-fsl.c
+++ b/drivers/usb/host/ehci-fsl.c
@@ -278,6 +278,10 @@ static int ehci_fsl_usb_setup(struct ehci_hcd *ehci)
 		out_be32(non_ehci + FSL_SOC_USB_SNOOP2, 0x80000000 | SNOOP_SIZE_2GB);
 	}
 
+	/* Deal with USB erratum A-005275 */
+	if (pdata->has_fsl_erratum_a005275 == 1)
+		ehci->has_fsl_hs_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 22abb68..fb381cf 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -1222,6 +1222,13 @@ int ehci_hub_control(
 				ehci->reset_done [wIndex] = jiffies
 						+ msecs_to_jiffies (50);
 			}
+
+			/* Force full-speed connect for FSL high-speed erratum;
+			 * disable HS Chirp by setting PFSC bit
+			 */
+			if (ehci_has_fsl_hs_errata(ehci))
+				temp |= (1 << PORTSC_FSL_PFSC);
+
 			ehci_writel(ehci, temp, status_reg);
 			break;
 
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index f700157..c232838 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -215,6 +215,7 @@ struct ehci_hcd {			/* one per controller */
 	/* SILICON QUIRKS */
 	unsigned		no_selective_suspend:1;
 	unsigned		has_fsl_port_bug:1; /* FreeScale */
+	unsigned		has_fsl_hs_errata:1;	/* Freescale HS quirk */
 	unsigned		big_endian_mmio:1;
 	unsigned		big_endian_desc:1;
 	unsigned		big_endian_capbase:1;
@@ -675,6 +676,17 @@ ehci_port_speed(struct ehci_hcd *ehci, unsigned int portsc)
 #define	ehci_port_speed(ehci, portsc)	USB_PORT_STAT_HIGH_SPEED
 #endif
 
+#define PORTSC_FSL_PFSC	24	/* Port Force Full-Speed Connect */
+
+#if defined(CONFIG_PPC_85xx)
+/* Some Freescale processors have an erratum (USB A-005275) in which
+ * incoming packets get corrupted in HS mode
+ */
+#define ehci_has_fsl_hs_errata(e)	((e)->has_fsl_hs_errata)
+#else
+#define ehci_has_fsl_hs_errata(e)	(0)
+#endif
+
 /*-------------------------------------------------------------------------*/
 
 #ifdef CONFIG_PPC_83xx
diff --git a/drivers/usb/host/fsl-mph-dr-of.c b/drivers/usb/host/fsl-mph-dr-of.c
index 9f73141..534c4c5 100644
--- a/drivers/usb/host/fsl-mph-dr-of.c
+++ b/drivers/usb/host/fsl-mph-dr-of.c
@@ -221,6 +221,10 @@ static int fsl_usb2_mph_dr_of_probe(struct platform_device *ofdev)
 		pdata->has_fsl_erratum_a007792 = 1;
 	else
 		pdata->has_fsl_erratum_a007792 = 0;
+	if (of_get_property(np, "fsl,usb-erratum-a005275", NULL))
+		pdata->has_fsl_erratum_a005275 = 1;
+	else
+		pdata->has_fsl_erratum_a005275 = 0;
 
 	/*
 	 * Determine whether phy_clk_valid needs to be checked
diff --git a/include/linux/fsl_devices.h b/include/linux/fsl_devices.h
index cebdbbb..f291291 100644
--- a/include/linux/fsl_devices.h
+++ b/include/linux/fsl_devices.h
@@ -99,6 +99,7 @@ struct fsl_usb2_platform_data {
 	unsigned	suspended:1;
 	unsigned	already_suspended:1;
 	unsigned        has_fsl_erratum_a007792:1;
+	unsigned        has_fsl_erratum_a005275:1;
 	unsigned        check_phy_clk_valid:1;
 
 	/* register save area for suspend/resume */
-- 
2.1.0

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