HID: intel-ish-hid: ipc: set NO_D3 flag only when needed

Currently, the NO_D3 flag is set in ish_probe(), and cleared in
ish_remove(). So even if the system goes into S3, ISH is still
in D0i3 state. It makes more sense that put ISH into D3 as system
goes into S3 and put ISH into D0i3 as system goes into suspend-to-idle.
I remove the NO_D3 setting in ish_probe(), so that ISH can enter
D3 state when system enters S3. Only set N0_D3 flag when system
enters the suspend-to-idle or platform specified, and clear it
when system resume.

When the ISH enters D3, the FW will check the DMA bit status.
If the DMA bit is set, the FW will reset automatically. So the
DMA bit need be clear before putting ISH into D3 state.

Signed-off-by: Zhang Lixu <lixu.zhang@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/intel-ish-hid/ipc/hw-ish.h

@@ -77,5 +77,6 @@ irqreturn_t ish_irq_handler(int irq, void *dev_id);
 struct ishtp_device *ish_dev_init(struct pci_dev *pdev);
 int ish_hw_start(struct ishtp_device *dev);
 void ish_device_disable(struct ishtp_device *dev);
+int ish_disable_dma(struct ishtp_device *dev);
 
 #endif /* _ISHTP_HW_ISH_H_ */

drivers/hid/intel-ish-hid/ipc/ipc.c

@@ -672,7 +672,7 @@ eoi:
  *
  * Return: 0 for success else error code.
  */
-static int ish_disable_dma(struct ishtp_device *dev)
+int ish_disable_dma(struct ishtp_device *dev)
 {
 	unsigned int	dma_delay;
 

drivers/hid/intel-ish-hid/ipc/pci-ish.c

@@ -14,6 +14,7 @@
 #include <linux/types.h>
 #include <linux/pci.h>
 #include <linux/sched.h>
+#include <linux/suspend.h>
 #include <linux/interrupt.h>
 #include <linux/workqueue.h>
 #define CREATE_TRACE_POINTS
@@ -97,6 +98,11 @@ static const struct pci_device_id ish_invalid_pci_ids[] = {
 	{}
 };
 
+static inline bool ish_should_enter_d0i3(struct pci_dev *pdev)
+{
+	return !pm_suspend_via_firmware() || pdev->device == CHV_DEVICE_ID;
+}
+
 /**
  * ish_probe() - PCI driver probe callback
  * @pdev:	pci device
@@ -147,7 +153,6 @@ static int ish_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	/* mapping IO device memory */
 	hw->mem_addr = pcim_iomap_table(pdev)[0];
 	ishtp->pdev = pdev;
-	pdev->dev_flags |= PCI_DEV_FLAGS_NO_D3;
 
 	/* request and enable interrupt */
 	ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
@@ -184,7 +189,6 @@ static void ish_remove(struct pci_dev *pdev)
 	struct ishtp_device *ishtp_dev = pci_get_drvdata(pdev);
 
 	ishtp_bus_remove_all_clients(ishtp_dev, false);
-	pdev->dev_flags &= ~PCI_DEV_FLAGS_NO_D3;
 	ish_device_disable(ishtp_dev);
 }
 
@@ -209,6 +213,8 @@ static void __maybe_unused ish_resume_handler(struct work_struct *work)
 	uint32_t fwsts;
 	int ret;
 
+	pdev->dev_flags &= ~PCI_DEV_FLAGS_NO_D3;
+
 	/* Get ISH FW status */
 	fwsts = IPC_GET_ISH_FWSTS(dev->ops->get_fw_status(dev));
 
@@ -267,6 +273,17 @@ static int __maybe_unused ish_suspend(struct device *device)
 						 !dev->suspend_flag,
 						  msecs_to_jiffies(25));
 
+	if (ish_should_enter_d0i3(pdev)) {
+		/* Set the NO_D3 flag, the ISH would enter D0i3 */
+		pdev->dev_flags |= PCI_DEV_FLAGS_NO_D3;
+	} else {
+		/*
+		 * Clear the DMA bit before putting ISH into D3,
+		 * or ISH FW would reset automatically.
+		 */
+		ish_disable_dma(dev);
+	}
+
 	return 0;
 }