mfd: lpc_ich: Add support for iTCO v3

Some newer Atom CPUs, eg Avoton and Bay Trail, use slightly different
register layouts for the iTCO than the current v1 and v2 iTCO.
Differences from previous iTCO versions include:
- The ACPI space is enabled in the "ACPI base address" register instead
  of the "ACPI control register"

- The "no reboot" functionality is set in the "Power Management
  Configuration" register instead of the "General Control and Status"
  (GCS) register or PCI configuration space.

- The "ACPI Control Register" is not present on v3.  The "Power
  Management Configuration Base Address" register resides at the same
  address is Avoton/Bay Trail.

To differentiate these newer chipsets create a new v3 iTCO version and
update the MFD driver to support them.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Tested-by: Rajat Jain <rajatjain@juniper.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/lpc_ich.c

@@ -71,9 +71,11 @@
 #define ACPIBASE_GPE_END	0x2f
 #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 ACPICTRL		0x44
+#define ACPICTRL_PMCBASE	0x44
 
 #define ACPIBASE_GCS_OFF	0x3410
 #define ACPIBASE_GCS_END	0x3414
@@ -93,11 +95,12 @@ struct lpc_ich_priv {
 	int chipset;
 
 	int abase;		/* ACPI base */
-	int actrl;		/* ACPI control or PMC base */
+	int actrl_pbase;	/* ACPI control or PMC base */
 	int gbase;		/* GPIO base */
 	int gctrl;		/* GPIO control */
 
-	int actrl_save;		/* Cached ACPI control base value */
+	int abase_save;		/* Cached ACPI base value */
+	int actrl_pbase_save;		/* Cached ACPI control or PMC base value */
 	int gctrl_save;		/* Cached GPIO control value */
 };
 
@@ -110,7 +113,7 @@ static struct resource wdt_ich_res[] = {
 	{
 		.flags = IORESOURCE_IO,
 	},
-	/* GCS */
+	/* GCS or PMC */
 	{
 		.flags = IORESOURCE_MEM,
 	},
@@ -742,9 +745,15 @@ static void lpc_ich_restore_config_space(struct pci_dev *dev)
 {
 	struct lpc_ich_priv *priv = pci_get_drvdata(dev);
 
-	if (priv->actrl_save >= 0) {
-		pci_write_config_byte(dev, priv->actrl, priv->actrl_save);
-		priv->actrl_save = -1;
+	if (priv->abase_save >= 0) {
+		pci_write_config_byte(dev, priv->abase, priv->abase_save);
+		priv->abase_save = -1;
+	}
+
+	if (priv->actrl_pbase_save >= 0) {
+		pci_write_config_byte(dev, priv->actrl_pbase,
+			priv->actrl_pbase_save);
+		priv->actrl_pbase_save = -1;
 	}
 
 	if (priv->gctrl_save >= 0) {
@@ -758,9 +767,26 @@ static void lpc_ich_enable_acpi_space(struct pci_dev *dev)
 	struct lpc_ich_priv *priv = pci_get_drvdata(dev);
 	u8 reg_save;
 
-	pci_read_config_byte(dev, priv->actrl, &reg_save);
-	pci_write_config_byte(dev, priv->actrl, reg_save | 0x80);
-	priv->actrl_save = reg_save;
+	switch (lpc_chipset_info[priv->chipset].iTCO_version) {
+	case 3:
+		/*
+		 * Some chipsets (eg Avoton) enable the ACPI space in the
+		 * ACPI BASE register.
+		 */
+		pci_read_config_byte(dev, priv->abase, &reg_save);
+		pci_write_config_byte(dev, priv->abase, reg_save | 0x2);
+		priv->abase_save = reg_save;
+		break;
+	default:
+		/*
+		 * Most chipsets enable the ACPI space in the ACPI control
+		 * register.
+		 */
+		pci_read_config_byte(dev, priv->actrl_pbase, &reg_save);
+		pci_write_config_byte(dev, priv->actrl_pbase, reg_save | 0x80);
+		priv->actrl_pbase_save = reg_save;
+		break;
+	}
 }
 
 static void lpc_ich_enable_gpio_space(struct pci_dev *dev)
@@ -773,6 +799,17 @@ static void lpc_ich_enable_gpio_space(struct pci_dev *dev)
 	priv->gctrl_save = reg_save;
 }
 
+static void lpc_ich_enable_pmc_space(struct pci_dev *dev)
+{
+	struct lpc_ich_priv *priv = pci_get_drvdata(dev);
+	u8 reg_save;
+
+	pci_read_config_byte(dev, priv->actrl_pbase, &reg_save);
+	pci_write_config_byte(dev, priv->actrl_pbase, reg_save | 0x2);
+
+	priv->actrl_pbase_save = reg_save;
+}
+
 static void lpc_ich_finalize_cell(struct pci_dev *dev, struct mfd_cell *cell)
 {
 	struct lpc_ich_priv *priv = pci_get_drvdata(dev);
@@ -910,14 +947,20 @@ static int lpc_ich_init_wdt(struct pci_dev *dev)
 	lpc_ich_enable_acpi_space(dev);
 
 	/*
+	 * iTCO v2:
 	 * Get the Memory-Mapped GCS register. To get access to it
 	 * we have to read RCBA from PCI Config space 0xf0 and use
 	 * it as base. GCS = RCBA + ICH6_GCS(0x3410).
+	 *
+	 * iTCO v3:
+	 * Get the Power Management Configuration register.  To get access
+	 * to it we have to read the PMC BASE from config space and address
+	 * the register at offset 0x8.
 	 */
 	if (lpc_chipset_info[priv->chipset].iTCO_version == 1) {
 		/* Don't register iomem for TCO ver 1 */
 		lpc_ich_cells[LPC_WDT].num_resources--;
-	} else {
+	} else if (lpc_chipset_info[priv->chipset].iTCO_version == 2) {
 		pci_read_config_dword(dev, RCBABASE, &base_addr_cfg);
 		base_addr = base_addr_cfg & 0xffffc000;
 		if (!(base_addr_cfg & 1)) {
@@ -926,9 +969,17 @@ static int lpc_ich_init_wdt(struct pci_dev *dev)
 			ret = -ENODEV;
 			goto wdt_done;
 		}
-		res = wdt_mem_res(ICH_RES_MEM_GCS);
+		res = wdt_mem_res(ICH_RES_MEM_GCS_PMC);
 		res->start = base_addr + ACPIBASE_GCS_OFF;
 		res->end = base_addr + ACPIBASE_GCS_END;
+	} else if (lpc_chipset_info[priv->chipset].iTCO_version == 3) {
+		lpc_ich_enable_pmc_space(dev);
+		pci_read_config_dword(dev, ACPICTRL_PMCBASE, &base_addr_cfg);
+		base_addr = base_addr_cfg & 0xfffffe00;
+
+		res = wdt_mem_res(ICH_RES_MEM_GCS_PMC);
+		res->start = base_addr + ACPIBASE_PMC_OFF;
+		res->end = base_addr + ACPIBASE_PMC_END;
 	}
 
 	lpc_ich_finalize_cell(dev, &lpc_ich_cells[LPC_WDT]);
@@ -953,9 +1004,11 @@ static int lpc_ich_probe(struct pci_dev *dev,
 
 	priv->chipset = id->driver_data;
 
-	priv->actrl_save = -1;
+	priv->actrl_pbase_save = -1;
+	priv->abase_save = -1;
+
 	priv->abase = ACPIBASE;
-	priv->actrl = ACPICTRL;
+	priv->actrl_pbase = ACPICTRL_PMCBASE;
 
 	priv->gctrl_save = -1;
 	if (priv->chipset <= LPC_ICH5) {

include/linux/mfd/lpc_ich.h

@@ -21,10 +21,10 @@
 #define LPC_ICH_H
 
 /* Watchdog resources */
-#define ICH_RES_IO_TCO	0
-#define ICH_RES_IO_SMI	1
-#define ICH_RES_MEM_OFF	2
-#define ICH_RES_MEM_GCS	0
+#define ICH_RES_IO_TCO		0
+#define ICH_RES_IO_SMI		1
+#define ICH_RES_MEM_OFF		2
+#define ICH_RES_MEM_GCS_PMC	0
 
 /* GPIO resources */
 #define ICH_RES_GPIO	0