[U-Boot] [PATCH v4 1/1] tegra: usb: Fix device enumeration problem of USB1

[Marek Vasut <marek.vasut@gmail.com>]

Dear Jim Lin,

> A known hardware issue of USB1 port where bit 1 (connect status
> change) of PORTSC register will be set after issuing Port Reset
> (like "usb reset" in u-boot command line).
> This will be treated as an error and stops later device enumeration.
> 
> Therefore we clear that bit after Port Reset in order to proceed
> later device enumeration.
> 
> Signed-off-by: Jim Lin <jilin@nvidia.com>
> ---
> To reproduce this issue, you can modify board .dts file to set
> as the following to build u-boot binary.
> "
>  usb0 = "/usb at c5000000";
>  usb1 = "/usb at c5008000";
> "
> Install device on USB1 port (address at 0xc5000000).
> And run "usb reset" in u-boot console to enumerate device.
> 
> Before adding this patch, we could see problem every time.
> After adding, tried 10 times of "usb reset", "usb tree", "usb stop"
> , without seeing issue.
> 
> Changes in v4:
> - Add comment to describe replacing weak function ehci_powerup_fixup of
> ehci-hcd.c - Remove using variable my_reg
> 
> Changes in v3:
> - Move patch for USB1 controller into ehci_powerup_fixup of ehci-tegra.c
> - Update copyright year to 2012
> 
> Changes in v2:
> - Change config name
> - Add a callback function at the end of ehci_submit_root() function
> 
>  drivers/usb/host/ehci-tegra.c |   18 +++++++++++++++++-
>  1 files changed, 17 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c
> index a7e105b..6646d3a 100644
> --- a/drivers/usb/host/ehci-tegra.c
> +++ b/drivers/usb/host/ehci-tegra.c
> @@ -1,5 +1,5 @@
>  /*
> - * Copyright (c) 2009 NVIDIA Corporation
> + * Copyright (c) 2009-2012 NVIDIA Corporation
>   *
>   * See file CREDITS for list of people who contributed to this
>   * project.
> @@ -29,6 +29,22 @@
>  #include <asm/errno.h>
>  #include <asm/arch/usb.h>
> 
> +/*
> + * A known hardware issue where Connect Status Change bit of PORTSC
> register + * of USB1 controller will be set after Port Reset.
> + * We have to clear it in order for later device enumeration to proceed.
> + * This ehci_powerup_fixup overrides the weak function ehci_powerup_fixup
> + * in "ehci-hcd.c".
> + */
> +void ehci_powerup_fixup(uint32_t *status_reg, uint32_t *reg)

So it was even enough to use the already preinstalled callback? :-)

> +{
> +	mdelay(50);
> +	if (((u32) status_reg & 0xFFFFC000) != TEGRA_USB1_BASE)

What's this magic number here?

> +		return;
> +	/* For EHCI_PS_CSC to be cleared in ehci_hcd.c */
> +	if (ehci_readl(status_reg) & EHCI_PS_CSC)
> +		*reg |= EHCI_PS_CSC;

writel()

> +}
> 
>  /*
>   * Create the appropriate control structures to manage

Best regards,
Marek Vasut