dma: dw: Add suspend and resume handling for PCI mode DW_DMAC.

This is to disable/enable DW_DMAC hw during late suspend/early resume.
Since DMA is providing service to other clients (eg: SPI, HSUART),
we need to ensure DMA suspends after the clients and resume
before the clients are active.

Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/dw/pci.c

@@ -75,6 +75,36 @@ static void dw_pci_remove(struct pci_dev *pdev)
 		dev_warn(&pdev->dev, "can't remove device properly: %d\n", ret);
 }
 
+#ifdef CONFIG_PM_SLEEP
+
+static int dw_pci_suspend_late(struct device *dev)
+{
+	struct pci_dev *pci = to_pci_dev(dev);
+	struct dw_dma_chip *chip = pci_get_drvdata(pci);
+
+	return dw_dma_suspend(chip);
+};
+
+static int dw_pci_resume_early(struct device *dev)
+{
+	struct pci_dev *pci = to_pci_dev(dev);
+	struct dw_dma_chip *chip = pci_get_drvdata(pci);
+
+	return dw_dma_resume(chip);
+};
+
+#else /* !CONFIG_PM_SLEEP */
+
+#define dw_pci_suspend_late	NULL
+#define dw_pci_resume_early	NULL
+
+#endif /* !CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops dw_pci_dev_pm_ops = {
+	.suspend_late = dw_pci_suspend_late,
+	.resume_early = dw_pci_resume_early,
+};
+
 static DEFINE_PCI_DEVICE_TABLE(dw_pci_id_table) = {
 	/* Medfield */
 	{ PCI_VDEVICE(INTEL, 0x0827), (kernel_ulong_t)&dw_pci_pdata },
@@ -95,6 +125,9 @@ static struct pci_driver dw_pci_driver = {
 	.id_table	= dw_pci_id_table,
 	.probe		= dw_pci_probe,
 	.remove		= dw_pci_remove,
+	.driver	= {
+		.pm	= &dw_pci_dev_pm_ops,
+	},
 };
 
 module_pci_driver(dw_pci_driver);