[PATCH 4/4] watchdog: add support for Intel TCO watchdog timer
Ahmad Fatoum
ahmad at a3f.at
Fri Apr 16 07:24:36 BST 2021
Variants of the iTCO are integrated into many Intel southbridges.
They are most often accessed via PCI. Add a driver for the variant
found in the q35 QEMU machine.
It should be straight forward to extend the itco_chipset_info array
to support more variants in future as the need arises. To test, use:
qemu-system-x86_64 -M q35 -global ICH9-LPC.noreboot=false
The last option corresponds to a pin strap option, which can't be
influenced from within the VM.
Signed-off-by: Ahmad Fatoum <ahmad at a3f.at>
---
arch/x86/configs/efi_defconfig | 1 +
drivers/watchdog/Kconfig | 17 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/itco_wdt.c | 346 +++++++++++++++++++++++++++++++++
4 files changed, 365 insertions(+)
create mode 100644 drivers/watchdog/itco_wdt.c
diff --git a/arch/x86/configs/efi_defconfig b/arch/x86/configs/efi_defconfig
index e007bf8a0150..73614dd4b466 100644
--- a/arch/x86/configs/efi_defconfig
+++ b/arch/x86/configs/efi_defconfig
@@ -87,6 +87,7 @@ CONFIG_STATE_DRV=y
CONFIG_WATCHDOG=y
CONFIG_WATCHDOG_EFI=y
CONFIG_F71808E_WDT=y
+CONFIG_ITCO_WDT=y
# CONFIG_PINCTRL is not set
CONFIG_PCI_EFI=y
CONFIG_FS_EXT4=y
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index cf83b6a15bd4..76c1a89edc19 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -117,4 +117,21 @@ config F71808E_WDT
F71862FG, F71868, F71869, F71882FG, F71889FG, F81865 and F81866
Super I/O controllers.
+config ITCO_WDT
+ bool "Intel TCO Timer/Watchdog"
+ depends on X86
+ depends on PCI
+ help
+ Hardware driver for the intel TCO timer based watchdog devices.
+ These drivers are included in the Intel 82801 I/O Controller
+ Hub family (from ICH0 up to ICH10) and in the Intel 63xxESB
+ controller hub.
+
+ The TCO (Total Cost of Ownership) timer is a watchdog timer
+ that will reboot the machine after its second expiration.
+
+ On some motherboards the driver may fail to reset the chipset's
+ NO_REBOOT flag which prevents the watchdog from rebooting the
+ machine.
+
endif
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index dc9842770a62..b55c58cf3cb3 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -16,3 +16,4 @@ obj-$(CONFIG_RAVE_SP_WATCHDOG) += rave-sp-wdt.o
obj-$(CONFIG_STM32_IWDG_WATCHDOG) += stm32_iwdg.o
obj-$(CONFIG_STPMIC1_WATCHDOG) += stpmic1_wdt.o
obj-$(CONFIG_F71808E_WDT) += f71808e_wdt.o
+obj-$(CONFIG_ITCO_WDT) += itco_wdt.o
diff --git a/drivers/watchdog/itco_wdt.c b/drivers/watchdog/itco_wdt.c
new file mode 100644
index 000000000000..e7bd0fc99bbb
--- /dev/null
+++ b/drivers/watchdog/itco_wdt.c
@@ -0,0 +1,346 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * EFI Boot Guard, iTCO support (Version 3 and later)
+ *
+ * Copyright (c) 2006-2011 Wim Van Sebroeck <wim at iguana.be>.
+ * Copyright (c) 2019 Siemens AG
+ * Copyright (c) 2019 Ahmad Fatoum, Pengutronix
+ *
+ * Authors:
+ * Jan Kiszka <jan.kiszka at siemens.com>
+ * Christian Storm <christian.storm at siemens.com>
+ */
+
+#include <common.h>
+#include <init.h>
+#include <efi.h>
+#include <linux/pci.h>
+#include <watchdog.h>
+
+#define ACPIBASE 0x40
+#define ACPICTRL_PMCBASE 0x44
+
+#define PMBASE_ADDRMASK 0x0000ff80
+#define PMCBASE_ADDRMASK 0xfffffe00
+
+#define ACPIBASE_GCS_OFF 0x3410
+
+#define ACPIBASE_SMI_OFF 0x30
+#define ACPIBASE_SMI_END 0x33
+#define ACPIBASE_PMC_OFF 0x08
+#define ACPIBASE_PMC_END 0x0c
+#define ACPIBASE_TCO_OFF 0x60
+#define ACPIBASE_TCO_END 0x7f
+
+#define SMI_TCO_MASK (1 << 13)
+
+#define TCO_TMR_HLT_MASK (1 << 11)
+
+/* SMI Control and Enable Register */
+#define SMI_EN(itco) ((itco)->smibase)
+/* TCO base address */
+#define TCOBASE(itco) ((itco)->tcobase)
+
+#define TCO_RLD(p) (TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */
+#define TCOv1_TMR(p) (TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/
+#define TCO_DAT_IN(p) (TCOBASE(p) + 0x02) /* TCO Data In Register */
+#define TCO_DAT_OUT(p) (TCOBASE(p) + 0x03) /* TCO Data Out Register */
+#define TCO1_STS(p) (TCOBASE(p) + 0x04) /* TCO1 Status Register */
+#define TCO2_STS(p) (TCOBASE(p) + 0x06) /* TCO2 Status Register */
+#define TCO1_CNT(p) (TCOBASE(p) + 0x08) /* TCO1 Control Register */
+#define TCO2_CNT(p) (TCOBASE(p) + 0x0a) /* TCO2 Control Register */
+#define TCOv2_TMR(p) (TCOBASE(p) + 0x12) /* TCOv2 Timer Initial Value*/
+
+#define PMC_NO_REBOOT_MASK (1 << 4)
+
+#define RCBABASE 0xf0
+
+#define PCI_ID_ITCO_INTEL_ICH9 0x2918
+
+struct itco_priv;
+
+struct itco_info {
+ u32 pci_id;
+ const char *name;
+ u32 pmbase;
+ u32 smireg;
+ int (*update_no_reboot_bit)(struct itco_priv *itco, bool set);
+ unsigned version;
+};
+
+struct itco_priv {
+ struct pci_dev *pdev;
+ struct watchdog wdd;
+ void __iomem *io;
+ u32 smibase;
+ u32 tcobase;
+ void __iomem *gcs_pmc;
+ struct itco_info *info;
+ unsigned timeout;
+};
+
+static u32 itco_get_pmbase(struct itco_priv *itco)
+{
+ u32 pmbase = itco->info->pmbase;
+
+ if (!pmbase)
+ pci_read_config_dword(itco->pdev, ACPIBASE, &pmbase);
+
+ return pmbase & PMBASE_ADDRMASK;
+}
+
+static inline struct itco_priv *to_itco_priv(struct watchdog *wdd)
+{
+ return container_of(wdd, struct itco_priv, wdd);
+}
+
+static void itco_wdt_ping(struct itco_priv *itco)
+{
+ /* Reload the timer by writing to the TCO Timer Counter register */
+ outw(0x0001, TCO_RLD(itco));
+}
+
+static inline unsigned int seconds_to_ticks(struct itco_priv *itco, int secs)
+{
+ return itco->info->version == 3 ? secs : (secs * 10) / 6;
+}
+
+static inline unsigned int ticks_to_seconds(struct itco_priv *itco, int ticks)
+{
+ return itco->info->version == 3 ? ticks : (ticks * 6) / 10;
+}
+
+
+static int itco_wdt_start(struct itco_priv *itco, unsigned int timeout)
+{
+ unsigned tmrval;
+ u32 value;
+ int ret;
+
+ tmrval = seconds_to_ticks(itco, timeout);
+
+ /* Enable TCO SMIs */
+ value = inl(SMI_EN(itco)) | SMI_TCO_MASK;
+ outl(value, SMI_EN(itco));
+
+ /* Set timer value */
+ value = inw(TCOv2_TMR(itco));
+
+ value &= 0xfc00;
+ value |= tmrval & 0x3ff;
+
+ outw(value, TCOv2_TMR(itco));
+ value = inw(TCOv2_TMR(itco));
+
+ if ((value & 0x3ff) != tmrval)
+ return -EINVAL;
+
+ /* Force reloading of timer value */
+ outw(1, TCO_RLD(itco));
+
+ /* Clear NO_REBOOT flag */
+ ret = itco->info->update_no_reboot_bit(itco, false);
+ if (ret)
+ return ret;
+
+ /* Clear HLT flag to start timer */
+ value = inw(TCO1_CNT(itco)) & ~TCO_TMR_HLT_MASK;
+ outw(value, TCO1_CNT(itco));
+ value = inw(TCO1_CNT(itco));
+
+ if (value & 0x0800)
+ return -EIO;
+
+ return 0;
+}
+
+static int itco_wdt_stop(struct itco_priv *itco)
+{
+ u32 val;
+
+ /* Bit 11: TCO Timer Halt -> 1 = The TCO timer is disabled */
+ val = inw(TCO1_CNT(itco)) | 0x0800;
+ outw(val, TCO1_CNT(itco));
+ val = inb(TCO1_CNT(itco));
+
+ /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
+ itco->info->update_no_reboot_bit(itco, true);
+
+ if ((val & 0x0800) == 0)
+ return -EIO;
+ return 0;
+}
+
+static int itco_wdt_set_timeout(struct watchdog *wdd, unsigned int timeout)
+{
+ struct itco_priv *itco = to_itco_priv(wdd);
+ int ret;
+
+ if (!timeout)
+ return itco_wdt_stop(itco);
+
+ /* from the specs: */
+ /* "Values of 0h-3h are ignored and should not be attempted" */
+ if (timeout < 0x04)
+ return -EINVAL;
+
+ if (itco->timeout != timeout) {
+ ret = itco_wdt_start(itco, timeout);
+ if (ret) {
+ dev_err(wdd->hwdev, "Fail to (re)start watchdog\n");
+ return ret;
+ }
+ }
+
+ itco_wdt_ping(itco);
+ return 0;
+}
+
+static inline u32 no_reboot_bit(unsigned version)
+{
+ u32 enable_bit;
+
+ switch (version) {
+ case 5:
+ case 3:
+ enable_bit = 0x00000010;
+ break;
+ case 2:
+ enable_bit = 0x00000020;
+ break;
+ case 4:
+ case 1:
+ default:
+ enable_bit = 0x00000002;
+ break;
+ }
+
+ return enable_bit;
+}
+
+
+static int update_no_reboot_bit(struct itco_priv *itco, bool set)
+{
+ u32 val32 = 0, newval32 = 0;
+
+ val32 = readl(itco->gcs_pmc);
+ if (set)
+ val32 |= no_reboot_bit(itco->info->version);
+ else
+ val32 &= ~no_reboot_bit(itco->info->version);
+ writel(val32, itco->gcs_pmc);
+ newval32 = readl(itco->gcs_pmc);
+
+ /* make sure the update is successful */
+ if (val32 != newval32)
+ return -EPERM;
+
+ return 0;
+}
+
+static void lpc_ich_enable_acpi_space(struct itco_priv *itco)
+{
+ u8 reg_save;
+
+ pci_read_config_byte(itco->pdev, ACPICTRL_PMCBASE, ®_save);
+ pci_write_config_byte(itco->pdev, ACPICTRL_PMCBASE, reg_save | 0x80);
+}
+
+enum itco_chipsets {
+ ITCO_INTEL_ICH9,
+};
+
+/* version 1 not supported! */
+static struct itco_info itco_chipset_info[] = {
+ [ITCO_INTEL_ICH9] = {
+ .pci_id = PCI_ID_ITCO_INTEL_ICH9,
+ .name = "ICH9", /* QEmu machine q35 */
+ .smireg = 0x30,
+ .update_no_reboot_bit = update_no_reboot_bit,
+ .version = 2,
+ },
+};
+
+static int itco_wdt_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+ struct itco_priv *itco;
+ struct watchdog *wdd;
+ u32 rcba_base_cfg;
+ u32 pmbase;
+ int ret;
+ int i;
+
+ pci_enable_device(pdev);
+ pci_set_master(pdev);
+
+ itco = xzalloc(sizeof(*itco));
+
+ itco->pdev = pdev;
+
+ for (i = 0; i < ARRAY_SIZE(itco_chipset_info); i++) {
+ if (id->device == itco_chipset_info[i].pci_id) {
+ itco->info = &itco_chipset_info[i];
+ break;
+ }
+ }
+
+ if (!itco->info)
+ return -ENODEV;
+
+
+ pci_read_config_dword(itco->pdev, RCBABASE, &rcba_base_cfg);
+ if (!(rcba_base_cfg & 1)) {
+ dev_notice(&pdev->dev, "RCBA is disabled by hardware/BIOS, device disabled\n");
+ return -ENODEV;
+ }
+
+ pmbase = itco_get_pmbase(itco);
+ if (!pmbase) {
+ dev_notice(&itco->pdev->dev, "I/O space for ACPI uninitialized\n");
+ return -ENODEV;
+ }
+
+ itco->smibase = pmbase + ACPIBASE_SMI_OFF;
+ itco->tcobase = pmbase + ACPIBASE_TCO_OFF;
+
+ lpc_ich_enable_acpi_space(itco);
+
+ itco->gcs_pmc = IOMEM(rcba_base_cfg & 0xffffc000UL) + ACPIBASE_GCS_OFF;
+
+
+ dev_notice(&pdev->dev, "gcs_pmc = 0x%p, smibase = 0x%x, tcobase = 0x%x\n",
+ itco->gcs_pmc, itco->smibase, itco->tcobase);
+
+ wdd = &itco->wdd;
+ wdd->hwdev = &pdev->dev;
+ wdd->set_timeout = itco_wdt_set_timeout;
+
+ wdd->timeout_max = ticks_to_seconds(itco, 0x3ff);
+
+ outw(0x0008, TCO1_STS(itco)); /* Clear the Time Out Status bit */
+ outw(0x0002, TCO2_STS(itco)); /* Clear SECOND_TO_STS bit */
+ outw(0x0004, TCO2_STS(itco)); /* Clear BOOT_STS bit */
+
+ ret = watchdog_register(wdd);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to register watchdog device\n");
+ return ret;
+ }
+
+ dev_info(&pdev->dev, "probed Intel TCO %s watchdog\n", itco->info->name);
+
+ return 0;
+}
+
+
+static DEFINE_PCI_DEVICE_TABLE(itco_wdt_pci_tbl) = {
+ { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ID_ITCO_INTEL_ICH9) },
+ { /* sentinel */ },
+};
+
+static struct pci_driver itco_wdt_driver = {
+ .name = "itco_wdt",
+ .id_table = itco_wdt_pci_tbl,
+ .probe = itco_wdt_probe,
+};
+device_pci_driver(itco_wdt_driver);
--
2.31.0
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