On 2/26/20 5:21 AM, Mika Westerberg wrote:
> Martin noticed that nct6775 driver does not load properly on his system
> in v5.4+ kernels. The issue was bisected to commit b84398d6d7f9 ("i2c:
> i801: Use iTCO version 6 in Cannon Lake PCH and beyond") but it is
> likely not the culprit because the faulty code has been in the driver
> already since commit 9424693035a5 ("i2c: i801: Create iTCO device on
> newer Intel PCHs"). So more likely some commit that added PCI IDs of
> recent chipsets made the driver to create the iTCO_wdt device on Martins
> system.
>
> The issue was debugged to be PCI configuration access to the PMC device
> that is not present. This returns all 1's when read and this caused the
> iTCO_wdt driver to accidentally request resourses used by nct6775.
>
> It turns out that the SMI resource is only required for some ancient
> systems, not the ones supported by this driver. For this reason do not
> populate the SMI resource at all and drop all the related code. The
> driver now always populates the main I/O resource and only in case of SPT
> (Intel Sunrisepoint) compatible devices it adds another resource for the
> NO_REBOOT bit. These two resources are of different types so
> platform_get_resource() used by the iTCO_wdt driver continues to find
> the both resources at index 0.
>
> Link: https://lore.kernel.org/linux-hwmon/CAM1AHpQ4196tyD=HhBu-2donSsuogabkfP03v1YF26Q7_BgvgA@xxxxxxxxxxxxxx/
> Fixes: 9424693035a5 ("i2c: i801: Create iTCO device on newer Intel PCHs")
> Reported-by: Martin Volf <martin.volf.42@xxxxxxxxx>
> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-i801.c | 45 ++++++++++-------------------------
> 1 file changed, 12 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index ca4f096fef74..a9c03f5c3482 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -132,11 +132,6 @@
> #define TCOBASE 0x050
> #define TCOCTL 0x054
>
> -#define ACPIBASE 0x040
> -#define ACPIBASE_SMI_OFF 0x030
> -#define ACPICTRL 0x044
> -#define ACPICTRL_EN 0x080
> -
> #define SBREG_BAR 0x10
> #define SBREG_SMBCTRL 0xc6000c
> #define SBREG_SMBCTRL_DNV 0xcf000c
> @@ -1553,7 +1548,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev,
> pci_bus_write_config_byte(pci_dev->bus, devfn, 0xe1, hidden);
> spin_unlock(&p2sb_spinlock);
>
> - res = &tco_res[ICH_RES_MEM_OFF];
> + res = &tco_res[1];
> if (pci_dev->device == PCI_DEVICE_ID_INTEL_DNV_SMBUS)
> res->start = (resource_size_t)base64_addr + SBREG_SMBCTRL_DNV;
> else
> @@ -1563,7 +1558,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev,
> res->flags = IORESOURCE_MEM;
>
> return platform_device_register_resndata(&pci_dev->dev, "iTCO_wdt", -1,
> - tco_res, 3, &spt_tco_platform_data,
> + tco_res, 2, &spt_tco_platform_data,
> sizeof(spt_tco_platform_data));
> }
>
> @@ -1576,17 +1571,16 @@ static struct platform_device *
> i801_add_tco_cnl(struct i801_priv *priv, struct pci_dev *pci_dev,
> struct resource *tco_res)
> {
> - return platform_device_register_resndata(&pci_dev->dev, "iTCO_wdt", -1,
> - tco_res, 2, &cnl_tco_platform_data,
> - sizeof(cnl_tco_platform_data));
> + return platform_device_register_resndata(&pci_dev->dev,
> + "iTCO_wdt", -1, tco_res, 1, &cnl_tco_platform_data,
> + sizeof(cnl_tco_platform_data));
> }
>
> static void i801_add_tco(struct i801_priv *priv)
> {
> - u32 base_addr, tco_base, tco_ctl, ctrl_val;
> struct pci_dev *pci_dev = priv->pci_dev;
> - struct resource tco_res[3], *res;
> - unsigned int devfn;
> + struct resource tco_res[2], *res;
> + u32 tco_base, tco_ctl;
>
> /* If we have ACPI based watchdog use that instead */
> if (acpi_has_watchdog())
> @@ -1601,30 +1595,15 @@ static void i801_add_tco(struct i801_priv *priv)
> return;
>
> memset(tco_res, 0, sizeof(tco_res));
> -
> - res = &tco_res[ICH_RES_IO_TCO];
> - res->start = tco_base & ~1;
> - res->end = res->start + 32 - 1;
> - res->flags = IORESOURCE_IO;
> -
> /*
> - * Power Management registers.
> + * Always populate the main iTCO IO resource here. The second entry
> + * for NO_REBOOT MMIO is filled by the SPT specific function.
> */
> - devfn = PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 2);
> - pci_bus_read_config_dword(pci_dev->bus, devfn, ACPIBASE, &base_addr);
> -
> - res = &tco_res[ICH_RES_IO_SMI];
> - res->start = (base_addr & ~1) + ACPIBASE_SMI_OFF;
> - res->end = res->start + 3;
> + res = &tco_res[0];
> + res->start = tco_base & ~1;
> + res->end = res->start + 32 - 1;
> res->flags = IORESOURCE_IO;
>
> - /*
> - * Enable the ACPI I/O space.
> - */
> - pci_bus_read_config_dword(pci_dev->bus, devfn, ACPICTRL, &ctrl_val);
> - ctrl_val |= ACPICTRL_EN;
> - pci_bus_write_config_dword(pci_dev->bus, devfn, ACPICTRL, ctrl_val);
> -
> if (priv->features & FEATURE_TCO_CNL)
> priv->tco_pdev = i801_add_tco_cnl(priv, pci_dev, tco_res);
> else
>
