ACPI / LPSS: fix system hangup on BYT

index 93d1606..f6b71af 100644
@@ -499,14 +499,15 @@ static void acpi_lpss_set_ltr(struct device *dev, s32 val)
 /**
  * acpi_lpss_save_ctx() - Save the private registers of LPSS device
  * @dev: LPSS device
+ * @pdata: pointer to the private data of the LPSS device
  *
  * Most LPSS devices have private registers which may loose their context when
  * the device is powered down. acpi_lpss_save_ctx() saves those registers into
  * prv_reg_ctx array.
  */
-static void acpi_lpss_save_ctx(struct device *dev)
+static void acpi_lpss_save_ctx(struct device *dev,
+			       struct lpss_private_data *pdata)
 {
-	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
 	unsigned int i;
 
 	for (i = 0; i < LPSS_PRV_REG_COUNT; i++) {

@@ -521,12 +522,13 @@ static void acpi_lpss_save_ctx(struct device *dev)
 /**
  * acpi_lpss_restore_ctx() - Restore the private registers of LPSS device
  * @dev: LPSS device
+ * @pdata: pointer to the private data of the LPSS device
  *
  * Restores the registers that were previously stored with acpi_lpss_save_ctx().
  */
-static void acpi_lpss_restore_ctx(struct device *dev)
+static void acpi_lpss_restore_ctx(struct device *dev,
+				  struct lpss_private_data *pdata)
 {
-	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
 	unsigned int i;
 
 	/*

@@ -549,23 +551,31 @@ static void acpi_lpss_restore_ctx(struct device *dev)
 #ifdef CONFIG_PM_SLEEP
 static int acpi_lpss_suspend_late(struct device *dev)
 {
-	int ret = pm_generic_suspend_late(dev);
+	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+	int ret;
 
+	ret = pm_generic_suspend_late(dev);
 	if (ret)
 		return ret;
 
-	acpi_lpss_save_ctx(dev);
+	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
+		acpi_lpss_save_ctx(dev, pdata);
+
 	return acpi_dev_suspend_late(dev);
 }
 
 static int acpi_lpss_resume_early(struct device *dev)
 {
-	int ret = acpi_dev_resume_early(dev);
+	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+	int ret;
 
+	ret = acpi_dev_resume_early(dev);
 	if (ret)
 		return ret;
 
-	acpi_lpss_restore_ctx(dev);
+	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
+		acpi_lpss_restore_ctx(dev, pdata);
+
 	return pm_generic_resume_early(dev);
 }
 #endif /* CONFIG_PM_SLEEP */

@@ -573,23 +583,31 @@ static int acpi_lpss_resume_early(struct device *dev)
 #ifdef CONFIG_PM_RUNTIME
 static int acpi_lpss_runtime_suspend(struct device *dev)
 {
-	int ret = pm_generic_runtime_suspend(dev);
+	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+	int ret;
 
+	ret = pm_generic_runtime_suspend(dev);
 	if (ret)
 		return ret;
 
-	acpi_lpss_save_ctx(dev);
+	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
+		acpi_lpss_save_ctx(dev, pdata);
+
 	return acpi_dev_runtime_suspend(dev);
 }
 
 static int acpi_lpss_runtime_resume(struct device *dev)
 {
-	int ret = acpi_dev_runtime_resume(dev);
+	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+	int ret;
 
+	ret = acpi_dev_runtime_resume(dev);
 	if (ret)
 		return ret;
 
-	acpi_lpss_restore_ctx(dev);
+	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
+		acpi_lpss_restore_ctx(dev, pdata);
+
 	return pm_generic_runtime_resume(dev);
 }
 #endif /* CONFIG_PM_RUNTIME */

@@ -631,22 +649,21 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb,
 		return 0;
 
 	pdata = acpi_driver_data(adev);
-	if (!pdata || !pdata->mmio_base)
+	if (!pdata)
 		return 0;
 
-	if (pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
+	if (pdata->mmio_base &&
+	    pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
 		dev_err(&pdev->dev, "MMIO size insufficient to access LTR\n");
 		return 0;
 	}
 
 	switch (action) {
 	case BUS_NOTIFY_BOUND_DRIVER:
-		if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
-			pdev->dev.pm_domain = &acpi_lpss_pm_domain;
+		pdev->dev.pm_domain = &acpi_lpss_pm_domain;
 		break;
 	case BUS_NOTIFY_UNBOUND_DRIVER:
-		if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
-			pdev->dev.pm_domain = NULL;
+		pdev->dev.pm_domain = NULL;
 		break;
 	case BUS_NOTIFY_ADD_DEVICE:
 		if (pdata->dev_desc->flags & LPSS_LTR)

index f6b71af..4804ae3 100644
@@ -659,19 +659,17 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb,
 	}
 
 	switch (action) {
-	case BUS_NOTIFY_BOUND_DRIVER:
-		pdev->dev.pm_domain = &acpi_lpss_pm_domain;
-		break;
-	case BUS_NOTIFY_UNBOUND_DRIVER:
-		pdev->dev.pm_domain = NULL;
-		break;
 	case BUS_NOTIFY_ADD_DEVICE:
+		pdev->dev.pm_domain = &acpi_lpss_pm_domain;
 		if (pdata->dev_desc->flags & LPSS_LTR)
 			return sysfs_create_group(&pdev->dev.kobj,
 						  &lpss_attr_group);
+		break;
 	case BUS_NOTIFY_DEL_DEVICE:
 		if (pdata->dev_desc->flags & LPSS_LTR)
 			sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
+		pdev->dev.pm_domain = NULL;
+		break;
 	default:
 		break;
 	}

index 4804ae3..d1dd0ad 100644
@@ -1,7 +1,7 @@
 /*
  * ACPI support for Intel Lynxpoint LPSS.
  *
- * Copyright (C) 2013, Intel Corporation
+ * Copyright (C) 2013, 2014, Intel Corporation
  * Authors: Mika Westerberg <[email protected]>
  *          Rafael J. Wysocki <[email protected]>
  *

@@ -60,6 +60,8 @@ ACPI_MODULE_NAME("acpi_lpss");
 #define LPSS_CLK_DIVIDER		BIT(2)
 #define LPSS_LTR			BIT(3)
 #define LPSS_SAVE_CTX			BIT(4)
+#define LPSS_DEV_PROXY			BIT(5)
+#define LPSS_PROXY_REQ			BIT(6)
 
 struct lpss_private_data;
 

@@ -70,8 +72,10 @@ struct lpss_device_desc {
 	void (*setup)(struct lpss_private_data *pdata);
 };
 
+static struct device *proxy_device;
+
 static struct lpss_device_desc lpss_dma_desc = {
-	.flags = LPSS_CLK,
+	.flags = LPSS_CLK | LPSS_PROXY_REQ,
 };
 
 struct lpss_private_data {

@@ -146,22 +150,24 @@ static struct lpss_device_desc byt_pwm_dev_desc = {
 };
 
 static struct lpss_device_desc byt_uart_dev_desc = {
-	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
+	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX |
+		 LPSS_DEV_PROXY,
 	.prv_offset = 0x800,
 	.setup = lpss_uart_setup,
 };
 
 static struct lpss_device_desc byt_spi_dev_desc = {
-	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
+	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX |
+		 LPSS_DEV_PROXY,
 	.prv_offset = 0x400,
 };
 
 static struct lpss_device_desc byt_sdio_dev_desc = {
-	.flags = LPSS_CLK,
+	.flags = LPSS_CLK | LPSS_DEV_PROXY,
 };
 
 static struct lpss_device_desc byt_i2c_dev_desc = {
-	.flags = LPSS_CLK | LPSS_SAVE_CTX,
+	.flags = LPSS_CLK | LPSS_SAVE_CTX | LPSS_DEV_PROXY,
 	.prv_offset = 0x800,
 	.setup = byt_i2c_setup,
 };

@@ -368,6 +374,8 @@ static int acpi_lpss_create_device(struct acpi_device *adev,
 	adev->driver_data = pdata;
 	pdev = acpi_create_platform_device(adev);
 	if (!IS_ERR_OR_NULL(pdev)) {
+		if (!proxy_device && dev_desc->flags & LPSS_DEV_PROXY)
+			proxy_device = &pdev->dev;
 		return 1;
 	}
 

@@ -593,7 +601,14 @@ static int acpi_lpss_runtime_suspend(struct device *dev)
 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
 		acpi_lpss_save_ctx(dev, pdata);
 
-	return acpi_dev_runtime_suspend(dev);
+	ret = acpi_dev_runtime_suspend(dev);
+	if (ret)
+		return ret;
+
+	if (pdata->dev_desc->flags & LPSS_PROXY_REQ && proxy_device)
+		return pm_runtime_put_sync_suspend(proxy_device);
+
+	return 0;
 }
 
 static int acpi_lpss_runtime_resume(struct device *dev)

@@ -601,6 +616,12 @@ static int acpi_lpss_runtime_resume(struct device *dev)
 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
 	int ret;
 
+	if (pdata->dev_desc->flags & LPSS_PROXY_REQ && proxy_device) {
+		ret = pm_runtime_get_sync(proxy_device);
+		if (ret)
+			return ret;
+	}
+
 	ret = acpi_dev_runtime_resume(dev);
 	if (ret)
 		return ret;

index 2447221..3804785 100644
@@ -22,6 +22,7 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/pm_runtime.h>
 
 #include "../dmaengine.h"
 #include "internal.h"

@@ -1504,6 +1505,9 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 	dw->regs = chip->regs;
 	chip->dw = dw;
 
+	pm_runtime_enable(chip->dev);
+	pm_runtime_get_sync(chip->dev);
+
 	dw_params = dma_read_byaddr(chip->regs, DW_PARAMS);
 	autocfg = dw_params >> DW_PARAMS_EN & 0x1;
 

@@ -1667,11 +1671,14 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 	dev_info(chip->dev, "DesignWare DMA Controller, %d channels\n",
 		 nr_channels);
 
+	pm_runtime_put_sync_suspend(chip->dev);
+
 	return 0;
 
 err_dma_register:
 	free_irq(chip->irq, dw);
 err_pdata:
+	pm_runtime_put_sync_suspend(chip->dev);
 	return err;
 }
 EXPORT_SYMBOL_GPL(dw_dma_probe);

@@ -1681,6 +1688,8 @@ int dw_dma_remove(struct dw_dma_chip *chip)
 	struct dw_dma		*dw = chip->dw;
 	struct dw_dma_chan	*dwc, *_dwc;
 
+	pm_runtime_get_sync(chip->dev);
+
 	dw_dma_off(dw);
 	dma_async_device_unregister(&dw->dma);
 

@@ -1693,6 +1702,8 @@ int dw_dma_remove(struct dw_dma_chip *chip)
 		channel_clear_bit(dw, CH_EN, dwc->mask);
 	}
 
+	pm_runtime_put_sync_suspend(chip->dev);
+	pm_runtime_disable(chip->dev);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(dw_dma_remove);