+ Tom Lendacky
On 1/6/22 12:18 PM, Guenter Roeck wrote:
> On Wed, Nov 03, 2021 at 11:15:20AM -0500, Terry Bowman wrote:
>> cd6h/cd7h port I/O can be disabled on recent AMD hardware. Read accesses to
>> disabled cd6h/cd7h port I/O will return F's and written data is dropped.
>>
>> The recommended workaround to handle disabled cd6h/cd7h port I/O is
>> replacing port I/O with MMIO accesses. The MMIO access method has been
>> available since at least SMBus controllers using PCI revision 0x59.
>>
>> The EFCH MMIO path is enabled in later patch.
>>
>> Co-developed-by: Robert Richter <rrichter@xxxxxxx>
>> Signed-off-by: Robert Richter <rrichter@xxxxxxx>
>> Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>
>> To: linux-watchdog@xxxxxxxxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Cc: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>
>> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
>> Cc: Robert Richter <rrichter@xxxxxxx>
>> ---
>> drivers/watchdog/sp5100_tco.c | 104 +++++++++++++++++++++++++++++++++-
>> drivers/watchdog/sp5100_tco.h | 6 ++
>> 2 files changed, 109 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
>> index 80ae42ae7aaa..4777e672a8ad 100644
>> --- a/drivers/watchdog/sp5100_tco.c
>> +++ b/drivers/watchdog/sp5100_tco.c
>> @@ -48,12 +48,14 @@
>> /* internal variables */
>>
>> enum tco_reg_layout {
>> - sp5100, sb800, efch
>> + sp5100, sb800, efch, efch_mmio
>> };
>>
>> struct sp5100_tco {
>> struct watchdog_device wdd;
>> void __iomem *tcobase;
>> + void __iomem *addr;
>> + struct resource *res;
>
> I must admit that I really don't like this code. Both res and
> addr are only used during initialization, yet their presence suggests
> runtime usage. Any chance to reqork this to not require those variables ?
>
> Guenter
>
Hi Guenter,
Yes, v3 will include refactoring to remove 'res' and 'addr'. I will also
correct the trailing newline you mentioned in an earlier email.
Regards,
Terry
>> enum tco_reg_layout tco_reg_layout;
>> };
>>
>> @@ -161,6 +163,59 @@ static void sp5100_tco_update_pm_reg8(u8 index, u8 reset, u8 set)
>> outb(val, SP5100_IO_PM_DATA_REG);
>> }
>>
>> +static int sp5100_request_region_mmio(struct device *dev,
>> + struct watchdog_device *wdd)
>> +{
>> + struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
>> + struct resource *res;
>> + void __iomem *addr;
>> +
>> + res = request_mem_region(EFCH_PM_ACPI_MMIO_PM_ADDR,
>> + EFCH_PM_ACPI_MMIO_PM_SIZE,
>> + "sp5100_tco");
>> +
>> + if (!res) {
>> + dev_err(dev,
>> + "SMB base address memory region 0x%x already in use.\n",
>> + EFCH_PM_ACPI_MMIO_PM_ADDR);
>> + return -EBUSY;
>> + }
>> +
>> + addr = ioremap(EFCH_PM_ACPI_MMIO_PM_ADDR,
>> + EFCH_PM_ACPI_MMIO_PM_SIZE);
>> + if (!addr) {
>> + release_resource(res);
>> + dev_err(dev, "SMB base address mapping failed.\n");
>> + return -ENOMEM;
>> + }
>> +
>> + tco->res = res;
>> + tco->addr = addr;
>> + return 0;
>> +}
>> +
>> +static void sp5100_release_region_mmio(struct sp5100_tco *tco)
>> +{
>> + iounmap(tco->addr);
>> + release_resource(tco->res);
>> +}
>> +
>> +static u8 efch_read_pm_reg8(struct sp5100_tco *tco, u8 index)
>> +{
>> + return readb(tco->addr + index);
>> +}
>> +
>> +static void efch_update_pm_reg8(struct sp5100_tco *tco,
>> + u8 index, u8 reset, u8 set)
>> +{
>> + u8 val;
>> +
>> + val = readb(tco->addr + index);
>> + val &= reset;
>> + val |= set;
>> + writeb(val, tco->addr + index);
>> +}
>> +
>> static void tco_timer_enable(struct sp5100_tco *tco)
>> {
>> u32 val;
>> @@ -201,6 +256,12 @@ static void tco_timer_enable(struct sp5100_tco *tco)
>> ~EFCH_PM_WATCHDOG_DISABLE,
>> EFCH_PM_DECODEEN_SECOND_RES);
>> break;
>> + case efch_mmio:
>> + /* Set the Watchdog timer resolution to 1 sec and enable */
>> + efch_update_pm_reg8(tco, EFCH_PM_DECODEEN3,
>> + ~EFCH_PM_WATCHDOG_DISABLE,
>> + EFCH_PM_DECODEEN_SECOND_RES);
>> + break;
>> }
>> }
>>
>> @@ -313,6 +374,44 @@ static int sp5100_tco_timer_init(struct sp5100_tco *tco)
>> return 0;
>> }
>>
>> +static int sp5100_tco_setupdevice_mmio(struct device *dev,
>> + struct watchdog_device *wdd)
>> +{
>> + struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
>> + const char *dev_name = SB800_DEVNAME;
>> + u32 mmio_addr = 0, alt_mmio_addr = 0;
>> + int ret;
>> +
>> + ret = sp5100_request_region_mmio(dev, wdd);
>> + if (ret)
>> + return ret;
>> +
>> + /* Determine MMIO base address */
>> + if (!(efch_read_pm_reg8(tco, EFCH_PM_DECODEEN) &
>> + EFCH_PM_DECODEEN_WDT_TMREN)) {
>> + efch_update_pm_reg8(tco, EFCH_PM_DECODEEN,
>> + 0xff,
>> + EFCH_PM_DECODEEN_WDT_TMREN);
>> + }
>> +
>> + if (efch_read_pm_reg8(tco, EFCH_PM_DECODEEN) &
>> + EFCH_PM_DECODEEN_WDT_TMREN)
>> + mmio_addr = EFCH_PM_WDT_ADDR;
>> +
>> + /* Determine alternate MMIO base address */
>> + if (efch_read_pm_reg8(tco, EFCH_PM_ISACONTROL) &
>> + EFCH_PM_ISACONTROL_MMIOEN)
>> + alt_mmio_addr = EFCH_PM_ACPI_MMIO_ADDR +
>> + EFCH_PM_ACPI_MMIO_WDT_OFFSET;
>> +
>> + ret = sp5100_tco_prepare_base(tco, mmio_addr, alt_mmio_addr, dev_name);
>> + if (!ret)
>> + ret = sp5100_tco_timer_init(tco);
>> +
>> + sp5100_release_region_mmio(tco);
>> + return ret;
>> +}
>> +
>> static int sp5100_tco_setupdevice(struct device *dev,
>> struct watchdog_device *wdd)
>> {
>> @@ -322,6 +421,9 @@ static int sp5100_tco_setupdevice(struct device *dev,
>> u32 alt_mmio_addr = 0;
>> int ret;
>>
>> + if (tco->tco_reg_layout == efch_mmio)
>> + return sp5100_tco_setupdevice_mmio(dev, wdd);
>> +
>> /* Request the IO ports used by this driver */
>> if (!request_muxed_region(SP5100_IO_PM_INDEX_REG,
>> SP5100_PM_IOPORTS_SIZE, "sp5100_tco")) {
>> diff --git a/drivers/watchdog/sp5100_tco.h b/drivers/watchdog/sp5100_tco.h
>> index adf015aa4126..73f179a1d6e5 100644
>> --- a/drivers/watchdog/sp5100_tco.h
>> +++ b/drivers/watchdog/sp5100_tco.h
>> @@ -83,3 +83,9 @@
>>
>> #define EFCH_PM_ACPI_MMIO_ADDR 0xfed80000
>> #define EFCH_PM_ACPI_MMIO_WDT_OFFSET 0x00000b00
>> +#define EFCH_PM_ACPI_MMIO_PM_OFFSET 0x00000300
>> +
>> +#define EFCH_PM_ACPI_MMIO_PM_ADDR (EFCH_PM_ACPI_MMIO_ADDR + \
>> + EFCH_PM_ACPI_MMIO_PM_OFFSET)
>> +#define EFCH_PM_ACPI_MMIO_PM_SIZE 8
>> +
