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Date: Wed, 3 Nov 2021 11:15:20 -0500
From: Terry Bowman <terry.bowman@....com>
To: <linux-watchdog@...r.kernel.org>
CC: <terry.bowman@....com>, <rrichter@....com>,
<linux-kernel@...r.kernel.org>, <wim@...ux-watchdog.org>,
<linux@...ck-us.net>, <ssg.sos.patches@....com>,
<sudheesh.mavila@....com>
Subject: [PATCH v2 3/4] Watchdog: sp5100_tco: Add EFCH SMBus controller initialization using MMIO
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@....com>
Signed-off-by: Robert Richter <rrichter@....com>
Signed-off-by: Terry Bowman <terry.bowman@....com>
To: linux-watchdog@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Cc: Wim Van Sebroeck <wim@...ux-watchdog.org>
Cc: Guenter Roeck <linux@...ck-us.net>
Cc: Robert Richter <rrichter@....com>
---
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;
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
+
--
2.25.1
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