[PATCH v4 3/4] Watchdog: sp5100_tco: Add initialization using EFCH MMIO

Terry Bowman
2022-01-30T19:13:10Z

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@amd.com>
Signed-off-by: Robert Richter <rrichter@amd.com>
Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Tested-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
---
drivers/watchdog/sp5100_tco.c | 100 +++++++++++++++++++++++++++++++++-
drivers/watchdog/sp5100_tco.h | 5 ++
2 files changed, 104 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index 16e122d5045e..1a5e76d13c3c 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;
}
}

@@ -307,6 +309,99 @@ 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;
+ u32 val;
+
+ res = request_mem_region_muxed(EFCH_PM_ACPI_MMIO_PM_ADDR,
+ EFCH_PM_ACPI_MMIO_PM_SIZE,
+ "sp5100_tco");
+
+ if (!res) {
+ dev_err(dev,
+ "Memory region 0x%08x 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) {
+ dev_err(dev, "Address mapping failed\n");
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ /*
+ * EFCH_PM_DECODEEN_WDT_TMREN is dual purpose. This bitfield
+ * enables sp5100_tco register MMIO space decoding. The bitfield
+ * also starts the timer operation. Enable if not already enabled.
+ */
+ val = efch_read_pm_reg8(addr, EFCH_PM_DECODEEN);
+ if (!(val & EFCH_PM_DECODEEN_WDT_TMREN)) {
+ efch_update_pm_reg8(addr, EFCH_PM_DECODEEN, 0xff,
+ EFCH_PM_DECODEEN_WDT_TMREN);
+ }
+
+ /* Error if the timer could not be enabled */
+ val = efch_read_pm_reg8(addr, EFCH_PM_DECODEEN);
+ if (!(val & EFCH_PM_DECODEEN_WDT_TMREN)) {
+ dev_err(dev, "Failed to enable the timer\n");
+ ret = -EFAULT;
+ goto out;
+ }
+
+ mmio_addr = EFCH_PM_WDT_ADDR;
+
+ /* Determine alternate MMIO base address */
+ val = efch_read_pm_reg8(addr, EFCH_PM_ISACONTROL);
+ if (val & 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);
+ }
+
+out:
+ if (addr)
+ iounmap(addr);
+
+ release_resource(res);
+
+ return ret;
+}
+
static int sp5100_tco_setupdevice(struct device *dev,
struct watchdog_device *wdd)
{
@@ -316,6 +411,9 @@ 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 daee872f9b71..8ca1b215e3ce 100644
--- a/drivers/watchdog/sp5100_tco.h
+++ b/drivers/watchdog/sp5100_tco.h
@@ -83,4 +83,9 @@
#define EFCH_PM_ISACONTROL_MMIOEN BIT(1)

#define EFCH_PM_ACPI_MMIO_ADDR 0xfed80000
+#define EFCH_PM_ACPI_MMIO_PM_OFFSET 0x00000300
#define EFCH_PM_ACPI_MMIO_WDT_OFFSET 0x00000b00
+
+#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
--
2.30.2