Merge branch 'pci/switchtec'

- Remove status check after submitting Switchtec MRPC Firmware Download
    commands to avoid Completion Timeouts (Kelvin Cao)

  - Set Switchtec coherent DMA mask to allow 64-bit DMA (Boris Glimcher)

  - Fix Switchtec SWITCHTEC_IOCTL_EVENT_IDX_ALL flag overwrite issue (Joey
    Zhang)

  - Enable write combining for Switchtec MRPC Input buffers (Kelvin Cao)

  - Add Switchtec MRPC DMA mode support (Wesley Sheng)

* pci/switchtec:
  switchtec: Add MRPC DMA mode support
  switchtec: Improve MRPC efficiency by enabling write combining
  switchtec: Fix SWITCHTEC_IOCTL_EVENT_IDX_ALL flags overwrite
  switchtec: Set DMA coherent mask
  switchtec: Remove immediate status check after submitting MRPC command

drivers/pci/switch/switchtec.c

@@ -13,7 +13,7 @@
 #include <linux/uaccess.h>
 #include <linux/poll.h>
 #include <linux/wait.h>
-
+#include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/nospec.h>
 
 MODULE_DESCRIPTION("Microsemi Switchtec(tm) PCIe Management Driver");
@@ -25,6 +25,11 @@ static int max_devices = 16;
 module_param(max_devices, int, 0644);
 MODULE_PARM_DESC(max_devices, "max number of switchtec device instances");
 
+static bool use_dma_mrpc = 1;
+module_param(use_dma_mrpc, bool, 0644);
+MODULE_PARM_DESC(use_dma_mrpc,
+		 "Enable the use of the DMA MRPC feature");
+
 static dev_t switchtec_devt;
 static DEFINE_IDA(switchtec_minor_ida);
 
@@ -113,6 +118,19 @@ static void stuser_set_state(struct switchtec_user *stuser,
 
 static void mrpc_complete_cmd(struct switchtec_dev *stdev);
 
+static void flush_wc_buf(struct switchtec_dev *stdev)
+{
+	struct ntb_dbmsg_regs __iomem *mmio_dbmsg;
+
+	/*
+	 * odb (outbound doorbell) register is processed by low latency
+	 * hardware and w/o side effect
+	 */
+	mmio_dbmsg = (void __iomem *)stdev->mmio_ntb +
+		SWITCHTEC_NTB_REG_DBMSG_OFFSET;
+	ioread32(&mmio_dbmsg->odb);
+}
+
 static void mrpc_cmd_submit(struct switchtec_dev *stdev)
 {
 	/* requires the mrpc_mutex to already be held when called */
@@ -128,16 +146,18 @@ static void mrpc_cmd_submit(struct switchtec_dev *stdev)
 	stuser = list_entry(stdev->mrpc_queue.next, struct switchtec_user,
 			    list);
 
+	if (stdev->dma_mrpc) {
+		stdev->dma_mrpc->status = SWITCHTEC_MRPC_STATUS_INPROGRESS;
+		memset(stdev->dma_mrpc->data, 0xFF, SWITCHTEC_MRPC_PAYLOAD_SIZE);
+	}
+
 	stuser_set_state(stuser, MRPC_RUNNING);
 	stdev->mrpc_busy = 1;
 	memcpy_toio(&stdev->mmio_mrpc->input_data,
 		    stuser->data, stuser->data_len);
+	flush_wc_buf(stdev);
 	iowrite32(stuser->cmd, &stdev->mmio_mrpc->cmd);
 
-	stuser->status = ioread32(&stdev->mmio_mrpc->status);
-	if (stuser->status != SWITCHTEC_MRPC_STATUS_INPROGRESS)
-		mrpc_complete_cmd(stdev);
-
 	schedule_delayed_work(&stdev->mrpc_timeout,
 			      msecs_to_jiffies(500));
 }
@@ -170,7 +190,11 @@ static void mrpc_complete_cmd(struct switchtec_dev *stdev)
 	stuser = list_entry(stdev->mrpc_queue.next, struct switchtec_user,
 			    list);
 
-	stuser->status = ioread32(&stdev->mmio_mrpc->status);
+	if (stdev->dma_mrpc)
+		stuser->status = stdev->dma_mrpc->status;
+	else
+		stuser->status = ioread32(&stdev->mmio_mrpc->status);
+
 	if (stuser->status == SWITCHTEC_MRPC_STATUS_INPROGRESS)
 		return;
 
@@ -180,13 +204,19 @@ static void mrpc_complete_cmd(struct switchtec_dev *stdev)
 	if (stuser->status != SWITCHTEC_MRPC_STATUS_DONE)
 		goto out;
 
-	stuser->return_code = ioread32(&stdev->mmio_mrpc->ret_value);
+	if (stdev->dma_mrpc)
+		stuser->return_code = stdev->dma_mrpc->rtn_code;
+	else
+		stuser->return_code = ioread32(&stdev->mmio_mrpc->ret_value);
 	if (stuser->return_code != 0)
 		goto out;
 
-	memcpy_fromio(stuser->data, &stdev->mmio_mrpc->output_data,
+	if (stdev->dma_mrpc)
-		      stuser->read_len);
+		memcpy(stuser->data, &stdev->dma_mrpc->data,
-
+			      stuser->read_len);
+	else
+		memcpy_fromio(stuser->data, &stdev->mmio_mrpc->output_data,
+			      stuser->read_len);
 out:
 	complete_all(&stuser->comp);
 	list_del_init(&stuser->list);
@@ -221,7 +251,10 @@ static void mrpc_timeout_work(struct work_struct *work)
 
 	mutex_lock(&stdev->mrpc_mutex);
 
-	status = ioread32(&stdev->mmio_mrpc->status);
+	if (stdev->dma_mrpc)
+		status = stdev->dma_mrpc->status;
+	else
+		status = ioread32(&stdev->mmio_mrpc->status);
 	if (status == SWITCHTEC_MRPC_STATUS_INPROGRESS) {
 		schedule_delayed_work(&stdev->mrpc_timeout,
 				      msecs_to_jiffies(500));
@@ -229,7 +262,6 @@ static void mrpc_timeout_work(struct work_struct *work)
 	}
 
 	mrpc_complete_cmd(stdev);
-
 out:
 	mutex_unlock(&stdev->mrpc_mutex);
 }
@@ -800,6 +832,7 @@ static int ioctl_event_ctl(struct switchtec_dev *stdev,
 {
 	int ret;
 	int nr_idxs;
+	unsigned int event_flags;
 	struct switchtec_ioctl_event_ctl ctl;
 
 	if (copy_from_user(&ctl, uctl, sizeof(ctl)))
@@ -821,7 +854,9 @@ static int ioctl_event_ctl(struct switchtec_dev *stdev,
 		else
 			return -EINVAL;
 
+		event_flags = ctl.flags;
 		for (ctl.index = 0; ctl.index < nr_idxs; ctl.index++) {
+			ctl.flags = event_flags;
 			ret = event_ctl(stdev, &ctl);
 			if (ret < 0)
 				return ret;
@@ -1017,10 +1052,24 @@ static void enable_link_state_events(struct switchtec_dev *stdev)
 	}
 }
 
+static void enable_dma_mrpc(struct switchtec_dev *stdev)
+{
+	writeq(stdev->dma_mrpc_dma_addr, &stdev->mmio_mrpc->dma_addr);
+	flush_wc_buf(stdev);
+	iowrite32(SWITCHTEC_DMA_MRPC_EN, &stdev->mmio_mrpc->dma_en);
+}
+
 static void stdev_release(struct device *dev)
 {
 	struct switchtec_dev *stdev = to_stdev(dev);
 
+	if (stdev->dma_mrpc) {
+		iowrite32(0, &stdev->mmio_mrpc->dma_en);
+		flush_wc_buf(stdev);
+		writeq(0, &stdev->mmio_mrpc->dma_addr);
+		dma_free_coherent(&stdev->pdev->dev, sizeof(*stdev->dma_mrpc),
+				stdev->dma_mrpc, stdev->dma_mrpc_dma_addr);
+	}
 	kfree(stdev);
 }
 
@@ -1176,10 +1225,27 @@ static irqreturn_t switchtec_event_isr(int irq, void *dev)
 	return ret;
 }
 
+
+static irqreturn_t switchtec_dma_mrpc_isr(int irq, void *dev)
+{
+	struct switchtec_dev *stdev = dev;
+	irqreturn_t ret = IRQ_NONE;
+
+	iowrite32(SWITCHTEC_EVENT_CLEAR |
+		  SWITCHTEC_EVENT_EN_IRQ,
+		  &stdev->mmio_part_cfg->mrpc_comp_hdr);
+	schedule_work(&stdev->mrpc_work);
+
+	ret = IRQ_HANDLED;
+	return ret;
+}
+
 static int switchtec_init_isr(struct switchtec_dev *stdev)
 {
 	int nvecs;
 	int event_irq;
+	int dma_mrpc_irq;
+	int rc;
 
 	nvecs = pci_alloc_irq_vectors(stdev->pdev, 1, 4,
 				      PCI_IRQ_MSIX | PCI_IRQ_MSI);
@@ -1194,9 +1260,29 @@ static int switchtec_init_isr(struct switchtec_dev *stdev)
 	if (event_irq < 0)
 		return event_irq;
 
-	return devm_request_irq(&stdev->pdev->dev, event_irq,
+	rc = devm_request_irq(&stdev->pdev->dev, event_irq,
 				switchtec_event_isr, 0,
 				KBUILD_MODNAME, stdev);
+
+	if (rc)
+		return rc;
+
+	if (!stdev->dma_mrpc)
+		return rc;
+
+	dma_mrpc_irq = ioread32(&stdev->mmio_mrpc->dma_vector);
+	if (dma_mrpc_irq < 0 || dma_mrpc_irq >= nvecs)
+		return -EFAULT;
+
+	dma_mrpc_irq  = pci_irq_vector(stdev->pdev, dma_mrpc_irq);
+	if (dma_mrpc_irq < 0)
+		return dma_mrpc_irq;
+
+	rc = devm_request_irq(&stdev->pdev->dev, dma_mrpc_irq,
+				switchtec_dma_mrpc_isr, 0,
+				KBUILD_MODNAME, stdev);
+
+	return rc;
 }
 
 static void init_pff(struct switchtec_dev *stdev)
@@ -1232,19 +1318,38 @@ static int switchtec_init_pci(struct switchtec_dev *stdev,
 			      struct pci_dev *pdev)
 {
 	int rc;
+	void __iomem *map;
+	unsigned long res_start, res_len;
 
 	rc = pcim_enable_device(pdev);
 	if (rc)
 		return rc;
 
-	rc = pcim_iomap_regions(pdev, 0x1, KBUILD_MODNAME);
+	rc = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64));
 	if (rc)
 		return rc;
 
 	pci_set_master(pdev);
 
-	stdev->mmio = pcim_iomap_table(pdev)[0];
+	res_start = pci_resource_start(pdev, 0);
-	stdev->mmio_mrpc = stdev->mmio + SWITCHTEC_GAS_MRPC_OFFSET;
+	res_len = pci_resource_len(pdev, 0);
+
+	if (!devm_request_mem_region(&pdev->dev, res_start,
+				     res_len, KBUILD_MODNAME))
+		return -EBUSY;
+
+	stdev->mmio_mrpc = devm_ioremap_wc(&pdev->dev, res_start,
+					   SWITCHTEC_GAS_TOP_CFG_OFFSET);
+	if (!stdev->mmio_mrpc)
+		return -ENOMEM;
+
+	map = devm_ioremap(&pdev->dev,
+			   res_start + SWITCHTEC_GAS_TOP_CFG_OFFSET,
+			   res_len - SWITCHTEC_GAS_TOP_CFG_OFFSET);
+	if (!map)
+		return -ENOMEM;
+
+	stdev->mmio = map - SWITCHTEC_GAS_TOP_CFG_OFFSET;
 	stdev->mmio_sw_event = stdev->mmio + SWITCHTEC_GAS_SW_EVENT_OFFSET;
 	stdev->mmio_sys_info = stdev->mmio + SWITCHTEC_GAS_SYS_INFO_OFFSET;
 	stdev->mmio_flash_info = stdev->mmio + SWITCHTEC_GAS_FLASH_INFO_OFFSET;
@@ -1262,6 +1367,19 @@ static int switchtec_init_pci(struct switchtec_dev *stdev,
 
 	pci_set_drvdata(pdev, stdev);
 
+	if (!use_dma_mrpc)
+		return 0;
+
+	if (ioread32(&stdev->mmio_mrpc->dma_ver) == 0)
+		return 0;
+
+	stdev->dma_mrpc = dma_zalloc_coherent(&stdev->pdev->dev,
+					      sizeof(*stdev->dma_mrpc),
+					      &stdev->dma_mrpc_dma_addr,
+					      GFP_KERNEL);
+	if (stdev->dma_mrpc == NULL)
+		return -ENOMEM;
+
 	return 0;
 }
 
@@ -1293,6 +1411,9 @@ static int switchtec_pci_probe(struct pci_dev *pdev,
 		  &stdev->mmio_part_cfg->mrpc_comp_hdr);
 	enable_link_state_events(stdev);
 
+	if (stdev->dma_mrpc)
+		enable_dma_mrpc(stdev);
+
 	rc = cdev_device_add(&stdev->cdev, &stdev->dev);
 	if (rc)
 		goto err_devadd;
@@ -1318,7 +1439,6 @@ static void switchtec_pci_remove(struct pci_dev *pdev)
 	cdev_device_del(&stdev->cdev, &stdev->dev);
 	ida_simple_remove(&switchtec_minor_ida, MINOR(stdev->dev.devt));
 	dev_info(&stdev->dev, "unregistered.\n");
-
 	stdev_kill(stdev);
 	put_device(&stdev->dev);
 }

include/linux/switchtec.h

@@ -29,6 +29,7 @@
 #define SWITCHTEC_EVENT_EN_IRQ   BIT(3)
 #define SWITCHTEC_EVENT_FATAL    BIT(4)
 
+#define SWITCHTEC_DMA_MRPC_EN	BIT(0)
 enum {
 	SWITCHTEC_GAS_MRPC_OFFSET       = 0x0000,
 	SWITCHTEC_GAS_TOP_CFG_OFFSET    = 0x1000,
@@ -46,6 +47,10 @@ struct mrpc_regs {
 	u32 cmd;
 	u32 status;
 	u32 ret_value;
+	u32 dma_en;
+	u64 dma_addr;
+	u32 dma_vector;
+	u32 dma_ver;
 } __packed;
 
 enum mrpc_status {
@@ -342,6 +347,14 @@ struct pff_csr_regs {
 
 struct switchtec_ntb;
 
+struct dma_mrpc_output {
+	u32 status;
+	u32 cmd_id;
+	u32 rtn_code;
+	u32 output_size;
+	u8 data[SWITCHTEC_MRPC_PAYLOAD_SIZE];
+};
+
 struct switchtec_dev {
 	struct pci_dev *pdev;
 	struct device dev;
@@ -381,6 +394,9 @@ struct switchtec_dev {
 	u8 link_event_count[SWITCHTEC_MAX_PFF_CSR];
 
 	struct switchtec_ntb *sndev;
+
+	struct dma_mrpc_output *dma_mrpc;
+	dma_addr_t dma_mrpc_dma_addr;
 };
 
 static inline struct switchtec_dev *to_stdev(struct device *dev)