linux-kernel - Re: [PATCH] sp5100_tco: properly check for new register layouts

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Date:	Tue, 3 May 2016 19:43:33 -0700
From:	Guenter Roeck <linux@...ck-us.net>
To:	Lucas Stach <dev@...xeye.de>, Wim Van Sebroeck <wim@...ana.be>
Cc:	linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] sp5100_tco: properly check for new register layouts

On 05/03/2016 10:15 AM, Lucas Stach wrote:
> Commits 190aa4304de6 (Add AMD Mullins platform support) and
> cca118fa2a0a94 (Add AMD Carrizo platform support) enabled the
> driver on a lot more devices, but the following commit missed
> a single location in the code when checking if the SB800 register
> offsets should be used. This leads to the wrong register being
> written which in turn causes ACPI to go haywire.
>
> Fix this by introducing a helper function to check for the new
> register layout and use this consistently.
>
> https://bugzilla.kernel.org/show_bug.cgi?id=114201
> https://bugzilla.redhat.com/show_bug.cgi?id=1329910
> Fixes: bdecfcdb5461 (sp5100_tco: fix the device check for SB800
> and later chipsets)
> Cc: stable@...r.kernel.org (4.5+)
> Signed-off-by: Lucas Stach <dev@...xeye.de>

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>   drivers/watchdog/sp5100_tco.c | 15 ++++++++++-----
>   1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
> index 6467b91..028618c 100644
> --- a/drivers/watchdog/sp5100_tco.c
> +++ b/drivers/watchdog/sp5100_tco.c
> @@ -73,6 +73,13 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started."
>   /*
>    * Some TCO specific functions
>    */
> +
> +static bool tco_has_sp5100_reg_layout(struct pci_dev *dev)
> +{
> +	return dev->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS &&
> +	       dev->revision < 0x40;
> +}
> +
>   static void tco_timer_start(void)
>   {
>   	u32 val;
> @@ -129,7 +136,7 @@ static void tco_timer_enable(void)
>   {
>   	int val;
>
> -	if (sp5100_tco_pci->revision >= 0x40) {
> +	if (!tco_has_sp5100_reg_layout(sp5100_tco_pci)) {
>   		/* For SB800 or later */
>   		/* Set the Watchdog timer resolution to 1 sec */
>   		outb(SB800_PM_WATCHDOG_CONFIG, SB800_IO_PM_INDEX_REG);
> @@ -342,8 +349,7 @@ static unsigned char sp5100_tco_setupdevice(void)
>   	/*
>   	 * Determine type of southbridge chipset.
>   	 */
> -	if (sp5100_tco_pci->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS &&
> -	    sp5100_tco_pci->revision < 0x40) {
> +	if (tco_has_sp5100_reg_layout(sp5100_tco_pci)) {
>   		dev_name = SP5100_DEVNAME;
>   		index_reg = SP5100_IO_PM_INDEX_REG;
>   		data_reg = SP5100_IO_PM_DATA_REG;
> @@ -388,8 +394,7 @@ static unsigned char sp5100_tco_setupdevice(void)
>   	 * Secondly, Find the watchdog timer MMIO address
>   	 * from SBResource_MMIO register.
>   	 */
> -	if (sp5100_tco_pci->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS &&
> -	    sp5100_tco_pci->revision < 0x40) {
> +	if (tco_has_sp5100_reg_layout(sp5100_tco_pci)) {
>   		/* Read SBResource_MMIO from PCI config(PCI_Reg: 9Ch) */
>   		pci_read_config_dword(sp5100_tco_pci,
>   				      SP5100_SB_RESOURCE_MMIO_BASE, &val);
>