This is a note to let you know that I've just added the patch titled
USB: EHCI: tegra: set txfill_tuning
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-ehci-tegra-set-txfill_tuning.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4f2fe2d27472f4a5dbd875888af4fc5175f3fdc5 Mon Sep 17 00:00:00 2001
From: Stephen Warren <swarren@xxxxxxxxxx>
Date: Mon, 14 Apr 2014 15:21:23 -0600
Subject: USB: EHCI: tegra: set txfill_tuning
From: Stephen Warren <swarren@xxxxxxxxxx>
commit 4f2fe2d27472f4a5dbd875888af4fc5175f3fdc5 upstream.
To avoid memory fetch underflows with larger USB transfers, Tegra SoCs
need txfill_tuning's txfifothresh register field set to a non-default
value. Add a custom reset override in order to set this up.
These values are recommended practice for all Tegra chips. However,
I've only noticed practical problems when not setting them this way on
systems using Tegra124. Hence, CC: stable only for recent kernels which
actually support Tegra124.
Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Tested-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/ehci-tegra.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
--- a/drivers/usb/host/ehci-tegra.c
+++ b/drivers/usb/host/ehci-tegra.c
@@ -513,8 +513,31 @@ static struct platform_driver tegra_ehci
}
};
+static int tegra_ehci_reset(struct usb_hcd *hcd)
+{
+ struct ehci_hcd *ehci = hcd_to_ehci(hcd);
+ int retval;
+ int txfifothresh;
+
+ retval = ehci_setup(hcd);
+ if (retval)
+ return retval;
+
+ /*
+ * We should really pull this value out of tegra_ehci_soc_config, but
+ * to avoid needing access to it, make use of the fact that Tegra20 is
+ * the only one so far that needs a value of 10, and Tegra20 is the
+ * only one which doesn't set has_hostpc.
+ */
+ txfifothresh = ehci->has_hostpc ? 0x10 : 10;
+ ehci_writel(ehci, txfifothresh << 16, &ehci->regs->txfill_tuning);
+
+ return 0;
+}
+
static const struct ehci_driver_overrides tegra_overrides __initconst = {
.extra_priv_size = sizeof(struct tegra_ehci_hcd),
+ .reset = tegra_ehci_reset,
};
static int __init ehci_tegra_init(void)
Patches currently in stable-queue which might be from swarren@xxxxxxxxxx are
queue-3.14/usb-ehci-tegra-set-txfill_tuning.patch
queue-3.14/clk-tegra-remove-non-existent-clocks.patch
queue-3.14/dt-tegra-remove-non-existent-clock-ids.patch
queue-3.14/arm-tegra-remove-uart5-uarte-from-tegra124.dtsi.patch
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