misc: mic: MIC host and card driver changes to enable VOP

This patch modifies the MIC host and card drivers to start using the
VOP driver. The MIC host and card drivers now implement the VOP bus
operations and register a VOP device on the VOP bus. MIC driver stack
documentation is also updated to include the new VOP driver.

Reviewed-by: Ashutosh Dixit <[e-mail]>
Signed-off-by: Sudeep Dutt <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/mic/mic_overview.txt

···
 
 Since it is a PCIe card, it does not have the ability to host hardware
 devices for networking, storage and console. We provide these devices
-on X100 coprocessors thus enabling a self-bootable equivalent environment
-for applications. A key benefit of our solution is that it leverages
-the standard virtio framework for network, disk and console devices,
-though in our case the virtio framework is used across a PCIe bus.
+on X100 coprocessors thus enabling a self-bootable equivalent
+environment for applications. A key benefit of our solution is that it
+leverages the standard virtio framework for network, disk and console
+devices, though in our case the virtio framework is used across a PCIe
+bus. A Virtio Over PCIe (VOP) driver allows creating user space
+backends or devices on the host which are used to probe virtio drivers
+for these devices on the MIC card. The existing VRINGH infrastructure
+in the kernel is used to access virtio rings from the host. The card
+VOP driver allows card virtio drivers to communicate with their user
+space backends on the host via a device page. Ring 3 apps on the host
+can add, remove and configure virtio devices. A thin MIC specific
+virtio_config_ops is implemented which is borrowed heavily from
+previous similar implementations in lguest and s390.
 
 MIC PCIe card has a dma controller with 8 channels. These channels are
 shared between the host s/w and the card s/w. 0 to 3 are used by host
···
 the host to initiate DMA's to/from the card using the MIC DMA engine and
 the fact that the virtio block storage backend can only be on the host.
 
-                                      |
                +----------+           |             +----------+
                | Card OS  |           |             | Host OS  |
                +----------+           |             +----------+
···
         | Virtio| |Virtio  | |Virtio| | |Virtio   |  |Virtio  | |Virtio  |
         | Net   | |Console | |Block | | |Net      |  |Console | |Block   |
         | Driver| |Driver  | |Driver| | |backend  |  |backend | |backend |
-        +-------+ +--------+ +------+ | +---------+  +--------+ +--------+
+        +---+---+ +---+----+ +--+---+ | +---------+  +----+---+ +--------+
             |         |         |     |      |            |         |
             |         |         |     |User  |            |         |
-            |         |         |     |------|------------|---------|-------
-            +-------------------+     |Kernel +--------------------------+
-                      |               |       | Virtio over PCIe IOCTLs  |
-                      |               |       +--------------------------+
-+-----------+         |               |                   |  +-----------+
-| MIC DMA   |         |      +------+ | +------+ +------+ |  | MIC DMA   |
-| Driver    |         |      | SCIF | | | SCIF | | COSM | |  | Driver    |
-+-----------+         |      +------+ | +------+ +--+---+ |  +-----------+
-      |               |         |     |    |        |     |        |
-+---------------+     |      +------+ | +--+---+ +--+---+ | +----------------+
-|MIC virtual Bus|     |      |SCIF  | | |SCIF  | | COSM | | |MIC virtual Bus |
-+---------------+     |      |HW Bus| | |HW Bus| | Bus  | | +----------------+
-      |               |      +------+ | +--+---+ +------+ |              |
-      |               |         |     |       |     |     |              |
-      |   +-----------+---+     |     |       |    +---------------+     |
-      |   |Intel MIC      |     |     |       |    |Intel MIC      |     |
-      +---|Card Driver    |     |     |       |    |Host Driver    |     |
-          +------------+--------+     |       +----+---------------+-----+
+            |         |         |     |------|------------|--+------|-------
+            +---------+---------+     |Kernel                |
+                      |               |                      |
+  +---------+     +---+----+ +------+ | +------+ +------+ +--+---+  +-------+
+  |MIC DMA  |     |  VOP   | | SCIF | | | SCIF | | COSM | | VOP  |  |MIC DMA|
+  +---+-----+     +---+----+ +--+---+ | +--+---+ +--+---+ +------+  +----+--+
+      |               |         |     |    |        |                    |
+  +---+-----+     +---+----+ +--+---+ | +--+---+ +--+---+ +------+  +----+--+
+  |MIC      |     |  VOP   | |SCIF  | | |SCIF  | | COSM | | VOP  |  | MIC   |
+  |HW Bus   |     |  HW Bus| |HW Bus| | |HW Bus| | Bus  | |HW Bus|  |HW Bus |
+  +---------+     +--------+ +--+---+ | +--+---+ +------+ +------+  +-------+
+      |               |         |     |       |     |                    |
+      |   +-----------+--+      |     |       |    +---------------+     |
+      |   |Intel MIC     |      |     |       |    |Intel MIC      |     |
+      |   |Card Driver   |      |     |       |    |Host Driver    |     |
+      +---+--------------+------+     |       +----+---------------+-----+
                  |                    |                   |
              +-------------------------------------------------------------+
              |                                                             |

Documentation/mic/mpssd/mpss

···
 
 exec=/usr/sbin/mpssd
 sysfs="/sys/class/mic"
-mic_modules="mic_host mic_x100_dma scif"
+mic_modules="mic_host mic_x100_dma scif vop"
 
 start()
 {

Documentation/mic/mpssd/mpssd.c

···
 	char path[PATH_MAX];
 	int fd, err;
 
-	snprintf(path, PATH_MAX, "/dev/mic%d", mic->id);
+	snprintf(path, PATH_MAX, "/dev/vop_virtio%d", mic->id);
 	fd = open(path, O_RDWR);
 	if (fd < 0) {
 		mpsslog("Could not open %s %s\n", path, strerror(errno));

drivers/misc/mic/Kconfig

···
 
 config INTEL_MIC_HOST
 	tristate "Intel MIC Host Driver"
-	depends on 64BIT && PCI && X86 && INTEL_MIC_BUS && SCIF_BUS && MIC_COSM
-	select VHOST_RING
+	depends on 64BIT && PCI && X86
+	depends on INTEL_MIC_BUS && SCIF_BUS && MIC_COSM && VOP_BUS
 	help
 	  This enables Host Driver support for the Intel Many Integrated
 	  Core (MIC) family of PCIe form factor coprocessor devices that
···
 
 config INTEL_MIC_CARD
 	tristate "Intel MIC Card Driver"
-	depends on 64BIT && X86 && INTEL_MIC_BUS && SCIF_BUS && MIC_COSM
+	depends on 64BIT && X86
+	depends on INTEL_MIC_BUS && SCIF_BUS && MIC_COSM && VOP_BUS
 	select VIRTIO
 	help
 	  This enables card driver support for the Intel Many Integrated

drivers/misc/mic/card/mic_device.c

···
 	.iounmap = ___mic_iounmap,
 };
 
+static inline struct mic_driver *vpdev_to_mdrv(struct vop_device *vpdev)
+{
+	return dev_get_drvdata(vpdev->dev.parent);
+}
+
+static struct mic_irq *
+__mic_request_irq(struct vop_device *vpdev,
+		  irqreturn_t (*func)(int irq, void *data),
+		   const char *name, void *data, int intr_src)
+{
+	return mic_request_card_irq(func, NULL, name, data, intr_src);
+}
+
+static void __mic_free_irq(struct vop_device *vpdev,
+			   struct mic_irq *cookie, void *data)
+{
+	return mic_free_card_irq(cookie, data);
+}
+
+static void __mic_ack_interrupt(struct vop_device *vpdev, int num)
+{
+	struct mic_driver *mdrv = vpdev_to_mdrv(vpdev);
+
+	mic_ack_interrupt(&mdrv->mdev);
+}
+
+static int __mic_next_db(struct vop_device *vpdev)
+{
+	return mic_next_card_db();
+}
+
+static void __iomem *__mic_get_remote_dp(struct vop_device *vpdev)
+{
+	struct mic_driver *mdrv = vpdev_to_mdrv(vpdev);
+
+	return mdrv->dp;
+}
+
+static void __mic_send_intr(struct vop_device *vpdev, int db)
+{
+	struct mic_driver *mdrv = vpdev_to_mdrv(vpdev);
+
+	mic_send_intr(&mdrv->mdev, db);
+}
+
+static void __iomem *__mic_ioremap(struct vop_device *vpdev,
+				   dma_addr_t pa, size_t len)
+{
+	struct mic_driver *mdrv = vpdev_to_mdrv(vpdev);
+
+	return mic_card_map(&mdrv->mdev, pa, len);
+}
+
+static void __mic_iounmap(struct vop_device *vpdev, void __iomem *va)
+{
+	struct mic_driver *mdrv = vpdev_to_mdrv(vpdev);
+
+	mic_card_unmap(&mdrv->mdev, va);
+}
+
+static struct vop_hw_ops vop_hw_ops = {
+	.request_irq = __mic_request_irq,
+	.free_irq = __mic_free_irq,
+	.ack_interrupt = __mic_ack_interrupt,
+	.next_db = __mic_next_db,
+	.get_remote_dp = __mic_get_remote_dp,
+	.send_intr = __mic_send_intr,
+	.ioremap = __mic_ioremap,
+	.iounmap = __mic_iounmap,
+};
+
 static int mic_request_dma_chans(struct mic_driver *mdrv)
 {
 	dma_cap_mask_t mask;
 	struct dma_chan *chan;
 
-	request_module("mic_x100_dma");
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_MEMCPY, mask);
 
···
 		rc = -ENODEV;
 		goto irq_uninit;
 	}
+	mdrv->vpdev = vop_register_device(mdrv->dev, VOP_DEV_TRNSP,
+					  NULL, &vop_hw_ops, 0,
+					  NULL, mdrv->dma_ch[0]);
+	if (IS_ERR(mdrv->vpdev)) {
+		rc = PTR_ERR(mdrv->vpdev);
+		goto dma_free;
+	}
 	bootparam = mdrv->dp;
 	node_id = ioread8(&bootparam->node_id);
 	mdrv->scdev = scif_register_device(mdrv->dev, MIC_SCIF_DEV,
···
 					   mdrv->num_dma_ch, true);
 	if (IS_ERR(mdrv->scdev)) {
 		rc = PTR_ERR(mdrv->scdev);
-		goto dma_free;
+		goto vop_remove;
 	}
 	mic_create_card_debug_dir(mdrv);
 done:
 	return rc;
+vop_remove:
+	vop_unregister_device(mdrv->vpdev);
 dma_free:
 	mic_free_dma_chans(mdrv);
 irq_uninit:
···
 {
 	mic_delete_card_debug_dir(mdrv);
 	scif_unregister_device(mdrv->scdev);
+	vop_unregister_device(mdrv->vpdev);
 	mic_free_dma_chans(mdrv);
 	mic_uninit_irq();
 	mic_dp_uninit();

drivers/misc/mic/card/mic_device.h

···
 #include <linux/interrupt.h>
 #include <linux/mic_bus.h>
 #include "../bus/scif_bus.h"
+#include "../bus/vop_bus.h"
 
 /**
  * struct mic_intr_info - Contains h/w specific interrupt sources info
···
  * @dma_ch - Array of DMA channels
  * @num_dma_ch - Number of DMA channels available
  * @scdev: SCIF device on the SCIF virtual bus.
+ * @vpdev: Virtio over PCIe device on the VOP virtual bus.
  */
 struct mic_driver {
 	char name[20];
···
 	struct dma_chan *dma_ch[MIC_MAX_DMA_CHAN];
 	int num_dma_ch;
 	struct scif_hw_dev *scdev;
+	struct vop_device *vpdev;
 };
 
 /**

drivers/misc/mic/card/mic_x100.c

···
 		goto done;
 	}
 
+	request_module("mic_x100_dma");
 	mic_init_card_debugfs();
 	ret = platform_device_register(&mic_platform_dev);
 	if (ret) {

drivers/misc/mic/host/mic_boot.c

···
 #include <linux/mic_common.h>
 #include <linux/mic_bus.h>
 #include "../bus/scif_bus.h"
+#include "../bus/vop_bus.h"
 #include "../common/mic_dev.h"
 #include "mic_device.h"
 #include "mic_smpt.h"
+
+static inline struct mic_device *vpdev_to_mdev(struct device *dev)
+{
+	return dev_get_drvdata(dev->parent);
+}
+
+static dma_addr_t
+_mic_dma_map_page(struct device *dev, struct page *page,
+		  unsigned long offset, size_t size,
+		  enum dma_data_direction dir, struct dma_attrs *attrs)
+{
+	void *va = phys_to_virt(page_to_phys(page)) + offset;
+	struct mic_device *mdev = vpdev_to_mdev(dev);
+
+	return mic_map_single(mdev, va, size);
+}
+
+static void _mic_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
+				size_t size, enum dma_data_direction dir,
+				struct dma_attrs *attrs)
+{
+	struct mic_device *mdev = vpdev_to_mdev(dev);
+
+	mic_unmap_single(mdev, dma_addr, size);
+}
+
+static const struct dma_map_ops _mic_dma_ops = {
+	.map_page = _mic_dma_map_page,
+	.unmap_page = _mic_dma_unmap_page,
+};
+
+static struct mic_irq *
+__mic_request_irq(struct vop_device *vpdev,
+		  irqreturn_t (*func)(int irq, void *data),
+		  const char *name, void *data, int intr_src)
+{
+	struct mic_device *mdev = vpdev_to_mdev(&vpdev->dev);
+
+	return mic_request_threaded_irq(mdev, func, NULL, name, data,
+					intr_src, MIC_INTR_DB);
+}
+
+static void __mic_free_irq(struct vop_device *vpdev,
+			   struct mic_irq *cookie, void *data)
+{
+	struct mic_device *mdev = vpdev_to_mdev(&vpdev->dev);
+
+	return mic_free_irq(mdev, cookie, data);
+}
+
+static void __mic_ack_interrupt(struct vop_device *vpdev, int num)
+{
+	struct mic_device *mdev = vpdev_to_mdev(&vpdev->dev);
+
+	mdev->ops->intr_workarounds(mdev);
+}
+
+static int __mic_next_db(struct vop_device *vpdev)
+{
+	struct mic_device *mdev = vpdev_to_mdev(&vpdev->dev);
+
+	return mic_next_db(mdev);
+}
+
+static void *__mic_get_dp(struct vop_device *vpdev)
+{
+	struct mic_device *mdev = vpdev_to_mdev(&vpdev->dev);
+
+	return mdev->dp;
+}
+
+static void __iomem *__mic_get_remote_dp(struct vop_device *vpdev)
+{
+	return NULL;
+}
+
+static void __mic_send_intr(struct vop_device *vpdev, int db)
+{
+	struct mic_device *mdev = vpdev_to_mdev(&vpdev->dev);
+
+	mdev->ops->send_intr(mdev, db);
+}
+
+static void __iomem *__mic_ioremap(struct vop_device *vpdev,
+				   dma_addr_t pa, size_t len)
+{
+	struct mic_device *mdev = vpdev_to_mdev(&vpdev->dev);
+
+	return mdev->aper.va + pa;
+}
+
+static void __mic_iounmap(struct vop_device *vpdev, void __iomem *va)
+{
+	/* nothing to do */
+}
+
+static struct vop_hw_ops vop_hw_ops = {
+	.request_irq = __mic_request_irq,
+	.free_irq = __mic_free_irq,
+	.ack_interrupt = __mic_ack_interrupt,
+	.next_db = __mic_next_db,
+	.get_dp = __mic_get_dp,
+	.get_remote_dp = __mic_get_remote_dp,
+	.send_intr = __mic_send_intr,
+	.ioremap = __mic_ioremap,
+	.iounmap = __mic_iounmap,
+};
 
 static inline struct mic_device *scdev_to_mdev(struct scif_hw_dev *scdev)
 {
···
 	dma_cap_mask_t mask;
 	struct dma_chan *chan;
 
-	request_module("mic_x100_dma");
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_MEMCPY, mask);
 
···
 		goto dma_free;
 	}
 
+	mdev->vpdev = vop_register_device(&mdev->pdev->dev,
+					  VOP_DEV_TRNSP, &_mic_dma_ops,
+					  &vop_hw_ops, id + 1, &mdev->aper,
+					  mdev->dma_ch[0]);
+	if (IS_ERR(mdev->vpdev)) {
+		rc = PTR_ERR(mdev->vpdev);
+		goto scif_remove;
+	}
+
 	rc = mdev->ops->load_mic_fw(mdev, NULL);
 	if (rc)
-		goto scif_remove;
+		goto vop_remove;
 	mic_smpt_restore(mdev);
 	mic_intr_restore(mdev);
 	mdev->intr_ops->enable_interrupts(mdev);
···
 	mdev->ops->write_spad(mdev, MIC_DPHI_SPAD, mdev->dp_dma_addr >> 32);
 	mdev->ops->send_firmware_intr(mdev);
 	goto unlock_ret;
+vop_remove:
+	vop_unregister_device(mdev->vpdev);
 scif_remove:
 	scif_unregister_device(mdev->scdev);
 dma_free:
···
 	 * will be the first to be registered and the last to be
 	 * unregistered.
 	 */
+	vop_unregister_device(mdev->vpdev);
 	scif_unregister_device(mdev->scdev);
 	mic_free_dma_chans(mdev);
 	mbus_unregister_device(mdev->dma_mbdev);

drivers/misc/mic/host/mic_device.h

···
 #include <linux/miscdevice.h>
 #include <linux/mic_bus.h>
 #include "../bus/scif_bus.h"
+#include "../bus/vop_bus.h"
 #include "../bus/cosm_bus.h"
 #include "mic_intr.h"
 
···
  * @dma_ch - Array of DMA channels
  * @num_dma_ch - Number of DMA channels available
  * @scdev: SCIF device on the SCIF virtual bus.
+ * @vpdev: Virtio over PCIe device on the VOP virtual bus.
  * @cosm_dev: COSM device
  */
 struct mic_device {
···
 	struct dma_chan *dma_ch[MIC_MAX_DMA_CHAN];
 	int num_dma_ch;
 	struct scif_hw_dev *scdev;
+	struct vop_device *vpdev;
 	struct cosm_device *cosm_dev;
 };
 

drivers/misc/mic/host/mic_main.c

···
 {
 	int ret;
 
+	request_module("mic_x100_dma");
 	mic_init_debugfs();
 	ida_init(&g_mic_ida);
 	ret = pci_register_driver(&mic_driver);