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Date: Mon, 24 Jan 2022 16:36:33 -0600
From: Terry Bowman <Terry.Bowman@....com>
To: Jean Delvare <jdelvare@...e.de>
Cc: linux@...ck-us.net, linux-watchdog@...r.kernel.org,
linux-i2c@...r.kernel.org, wsa@...nel.org,
andy.shevchenko@...il.com, rafael.j.wysocki@...el.com,
linux-kernel@...r.kernel.org, wim@...ux-watchdog.org,
rrichter@....com, thomas.lendacky@....com,
Nehal-bakulchandra.Shah@....com, Basavaraj.Natikar@....com,
Shyam-sundar.S-k@....com, Mario.Limonciello@....com
Subject: Re: [PATCH v3 3/4] Watchdog: sp5100_tco: Add initialization using
EFCH MMIO
On 1/24/22 11:36 AM, Jean Delvare wrote:
> Hi Terry,
>
> On Tue, 18 Jan 2022 14:22:33 -0600, 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. It is recommended to replace the cd6h/cd7h
>> port I/O with MMIO.
>>
>> Co-developed-by: Robert Richter <rrichter@....com>
>> Signed-off-by: Robert Richter <rrichter@....com>
>> Signed-off-by: Terry Bowman <terry.bowman@....com>
>> To: Guenter Roeck <linux@...ck-us.net>
>> To: linux-watchdog@...r.kernel.org
>> To: Jean Delvare <jdelvare@...e.com>
>> To: linux-i2c@...r.kernel.org
>> To: Wolfram Sang <wsa@...nel.org>
>> To: Andy Shevchenko <andy.shevchenko@...il.com>
>> To: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>> Cc: linux-kernel@...r.kernel.org
>> Cc: Wim Van Sebroeck <wim@...ux-watchdog.org>
>> Cc: Robert Richter <rrichter@....com>
>> Cc: Thomas Lendacky <thomas.lendacky@....com>
>> ---
>> drivers/watchdog/sp5100_tco.c | 88 ++++++++++++++++++++++++++++++++++-
>> drivers/watchdog/sp5100_tco.h | 5 ++
>> 2 files changed, 92 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
>> index 64ecebd93403..36519a992ca1 100644
>> --- a/drivers/watchdog/sp5100_tco.c
>> +++ b/drivers/watchdog/sp5100_tco.c
>> @@ -49,7 +49,7 @@
>> /* internal variables */
>>
>> enum tco_reg_layout {
>> - sp5100, sb800, efch
>> + sp5100, sb800, efch, efch_mmio
>> };
>>
>> struct sp5100_tco {
>> @@ -209,6 +209,8 @@ static void tco_timer_enable(struct sp5100_tco *tco)
>> ~EFCH_PM_WATCHDOG_DISABLE,
>> EFCH_PM_DECODEEN_SECOND_RES);
>> break;
>> + default:
>> + break;
>> }
>> }
>>
>> @@ -318,6 +320,87 @@ static int sp5100_tco_timer_init(struct sp5100_tco *tco)
>> return 0;
>> }
>>
>> +static u8 efch_read_pm_reg8(void __iomem *addr, u8 index)
>> +{
>> + return readb(addr + index);
>> +}
>> +
>> +static void efch_update_pm_reg8(void __iomem *addr, u8 index, u8 reset, u8 set)
>> +{
>> + u8 val;
>> +
>> + val = readb(addr + index);
>> + val &= reset;
>> + val |= set;
>> + writeb(val, addr + index);
>> +}
>> +
>> +static void tco_timer_enable_mmio(void __iomem *addr)
>> +{
>> + efch_update_pm_reg8(addr, EFCH_PM_DECODEEN3,
>> + ~EFCH_PM_WATCHDOG_DISABLE,
>> + EFCH_PM_DECODEEN_SECOND_RES);
>> +}
>> +
>> +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;
>> + struct resource *res;
>> + void __iomem *addr;
>> + int ret;
>> +
>> + 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",
>
> SMB -> SMBus
>
>> + 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");
>
> SMB -> SMBus
>
>> + return -ENOMEM;
>> + }
>> +
>
> A short comment saying what the next command is doing would be
> appreciated.
>
>> + if (!(efch_read_pm_reg8(addr, EFCH_PM_DECODEEN) &
>> + EFCH_PM_DECODEEN_WDT_TMREN)) {
>
> I find such splits hard to read. If checkpatch complains when you don't
> split it (but I think it no longer does, right?) then just introduce a
> local variable to store the register value. Same for the 2 occurrences
> below.
>
>> + efch_update_pm_reg8(addr, EFCH_PM_DECODEEN,
>> + 0xff,
>> + EFCH_PM_DECODEEN_WDT_TMREN);
>
> Easily fits in one fewer line.
>
>> + }
>> +
>> + /* Determine MMIO base address */
>> + if (efch_read_pm_reg8(addr, EFCH_PM_DECODEEN) &
>> + EFCH_PM_DECODEEN_WDT_TMREN)
>> + mmio_addr = EFCH_PM_WDT_ADDR;
>> +
>> + /* Determine alternate MMIO base address */
>> + if (efch_read_pm_reg8(addr, 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) {
>> + tco_timer_enable_mmio(addr);
>> + ret = sp5100_tco_timer_init(tco);
>> + }
>> +
>> + iounmap(addr);
>> + release_resource(res);
>> +
>> + return ret;
>> +}
>> +
>> static int sp5100_tco_setupdevice(struct device *dev,
>> struct watchdog_device *wdd)
>> {
>> @@ -327,6 +410,9 @@ 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..2df8f8b2c55b 100644
>> --- a/drivers/watchdog/sp5100_tco.h
>> +++ b/drivers/watchdog/sp5100_tco.h
>> @@ -83,3 +83,8 @@
>>
>> #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
>
> Other than these minor details, patch looks good to me, thanks.
>
> Tested-by: Jean Delvare <jdelvare@...e.de>
>
Hi Jean,
Is your "Tested-by" for patch 3/4 or the sp5100_tco series?
Regards,
Terry
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