diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl
index 8f6e3b2403c717f1d6df409440773b898f5af31c..4d4ce0e61e424708a94db666e0496d7c0f3fc253 100644
--- a/Documentation/DocBook/uio-howto.tmpl
+++ b/Documentation/DocBook/uio-howto.tmpl
@@ -25,6 +25,10 @@
2006-2008
Hans-Jürgen Koch.
+
+ 2009
+ Red Hat Inc, Michael S. Tsirkin (mst@redhat.com)
+
@@ -41,6 +45,13 @@ GPL version 2.
+
+ 0.9
+ 2009-07-16
+ mst
+ Added generic pci driver
+
+
0.8
2008-12-24
@@ -809,6 +820,158 @@ framework to set up sysfs files for this region. Simply leave it alone.
+
+
+Generic PCI UIO driver
+
+ The generic driver is a kernel module named uio_pci_generic.
+ It can work with any device compliant to PCI 2.3 (circa 2002) and
+ any compliant PCI Express device. Using this, you only need to
+ write the userspace driver, removing the need to write
+ a hardware-specific kernel module.
+
+
+
+Making the driver recognize the device
+
+Since the driver does not declare any device ids, it will not get loaded
+automatically and will not automatically bind to any devices, you must load it
+and allocate id to the driver yourself. For example:
+
+ modprobe uio_pci_generic
+ echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id
+
+
+
+If there already is a hardware specific kernel driver for your device, the
+generic driver still won't bind to it, in this case if you want to use the
+generic driver (why would you?) you'll have to manually unbind the hardware
+specific driver and bind the generic driver, like this:
+
+ echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
+ echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind
+
+
+
+You can verify that the device has been bound to the driver
+by looking for it in sysfs, for example like the following:
+
+ ls -l /sys/bus/pci/devices/0000:00:19.0/driver
+
+Which if successful should print
+
+ .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic
+
+Note that the generic driver will not bind to old PCI 2.2 devices.
+If binding the device failed, run the following command:
+
+ dmesg
+
+and look in the output for failure reasons
+
+
+
+
+Things to know about uio_pci_generic
+
+Interrupts are handled using the Interrupt Disable bit in the PCI command
+register and Interrupt Status bit in the PCI status register. All devices
+compliant to PCI 2.3 (circa 2002) and all compliant PCI Express devices should
+support these bits. uio_pci_generic detects this support, and won't bind to
+devices which do not support the Interrupt Disable Bit in the command register.
+
+
+On each interrupt, uio_pci_generic sets the Interrupt Disable bit.
+This prevents the device from generating further interrupts
+until the bit is cleared. The userspace driver should clear this
+bit before blocking and waiting for more interrupts.
+
+
+
+Writing userspace driver using uio_pci_generic
+
+Userspace driver can use pci sysfs interface, or the
+libpci libray that wraps it, to talk to the device and to
+re-enable interrupts by writing to the command register.
+
+
+
+Example code using uio_pci_generic
+
+Here is some sample userspace driver code using uio_pci_generic:
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+
+int main()
+{
+ int uiofd;
+ int configfd;
+ int err;
+ int i;
+ unsigned icount;
+ unsigned char command_high;
+
+ uiofd = open("/dev/uio0", O_RDONLY);
+ if (uiofd < 0) {
+ perror("uio open:");
+ return errno;
+ }
+ configfd = open("/sys/class/uio/uio0/device/config", O_RDWR);
+ if (uiofd < 0) {
+ perror("config open:");
+ return errno;
+ }
+
+ /* Read and cache command value */
+ err = pread(configfd, &command_high, 1, 5);
+ if (err != 1) {
+ perror("command config read:");
+ return errno;
+ }
+ command_high &= ~0x4;
+
+ for(i = 0;; ++i) {
+ /* Print out a message, for debugging. */
+ if (i == 0)
+ fprintf(stderr, "Started uio test driver.\n");
+ else
+ fprintf(stderr, "Interrupts: %d\n", icount);
+
+ /****************************************/
+ /* Here we got an interrupt from the
+ device. Do something to it. */
+ /****************************************/
+
+ /* Re-enable interrupts. */
+ err = pwrite(configfd, &command_high, 1, 5);
+ if (err != 1) {
+ perror("config write:");
+ break;
+ }
+
+ /* Wait for next interrupt. */
+ err = read(uiofd, &icount, 4);
+ if (err != 4) {
+ perror("uio read:");
+ break;
+ }
+
+ }
+ return errno;
+}
+
+
+
+
+
+
+
Further information
diff --git a/MAINTAINERS b/MAINTAINERS
index 837b5985ac40eea5490e85bb2cc5587be6220ef4..01193a4fe30e339feff943c538349ad447f04aaf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2218,6 +2218,13 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git
S: Maintained
F: include/asm-generic
+GENERIC UIO DRIVER FOR PCI DEVICES
+M: Michael S. Tsirkin
+L: kvm@vger.kernel.org
+L: linux-kernel@vger.kernel.org
+S: Supported
+F: drivers/uio/uio_pci_generic.c
+
GFS2 FILE SYSTEM
M: Steven Whitehouse
L: cluster-devel@redhat.com
diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
index 45200fd68534f67dc45f1395d18f7e21808f3b6d..8aa1955f35ed5f0099609565c0cdc89022f13396 100644
--- a/drivers/uio/Kconfig
+++ b/drivers/uio/Kconfig
@@ -84,4 +84,14 @@ config UIO_SERCOS3
If you compile this as a module, it will be called uio_sercos3.
+config UIO_PCI_GENERIC
+ tristate "Generic driver for PCI 2.3 and PCI Express cards"
+ depends on PCI
+ default n
+ help
+ Generic driver that you can bind, dynamically, to any
+ PCI 2.3 compliant and PCI Express card. It is useful,
+ primarily, for virtualization scenarios.
+ If you compile this as a module, it will be called uio_pci_generic.
+
endif
diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile
index 5c2586d75797685e8bb4aebeeee8a6d08ce2db8b..73b2e7516729eae8d882309273ce385540fb4188 100644
--- a/drivers/uio/Makefile
+++ b/drivers/uio/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_UIO_PDRV_GENIRQ) += uio_pdrv_genirq.o
obj-$(CONFIG_UIO_SMX) += uio_smx.o
obj-$(CONFIG_UIO_AEC) += uio_aec.o
obj-$(CONFIG_UIO_SERCOS3) += uio_sercos3.o
+obj-$(CONFIG_UIO_PCI_GENERIC) += uio_pci_generic.o
diff --git a/drivers/uio/uio_pci_generic.c b/drivers/uio/uio_pci_generic.c
new file mode 100644
index 0000000000000000000000000000000000000000..313da35984afece38a4614e427431d5ab4be6772
--- /dev/null
+++ b/drivers/uio/uio_pci_generic.c
@@ -0,0 +1,207 @@
+/* uio_pci_generic - generic UIO driver for PCI 2.3 devices
+ *
+ * Copyright (C) 2009 Red Hat, Inc.
+ * Author: Michael S. Tsirkin
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ *
+ * Since the driver does not declare any device ids, you must allocate
+ * id and bind the device to the driver yourself. For example:
+ *
+ * # echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id
+ * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
+ * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind
+ * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
+ * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic
+ *
+ * Driver won't bind to devices which do not support the Interrupt Disable Bit
+ * in the command register. All devices compliant to PCI 2.3 (circa 2002) and
+ * all compliant PCI Express devices should support this bit.
+ */
+
+#include
+#include
+#include
+#include
+#include
+
+#define DRIVER_VERSION "0.01.0"
+#define DRIVER_AUTHOR "Michael S. Tsirkin "
+#define DRIVER_DESC "Generic UIO driver for PCI 2.3 devices"
+
+struct uio_pci_generic_dev {
+ struct uio_info info;
+ struct pci_dev *pdev;
+ spinlock_t lock; /* guards command register accesses */
+};
+
+static inline struct uio_pci_generic_dev *
+to_uio_pci_generic_dev(struct uio_info *info)
+{
+ return container_of(info, struct uio_pci_generic_dev, info);
+}
+
+/* Interrupt handler. Read/modify/write the command register to disable
+ * the interrupt. */
+static irqreturn_t irqhandler(int irq, struct uio_info *info)
+{
+ struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
+ struct pci_dev *pdev = gdev->pdev;
+ irqreturn_t ret = IRQ_NONE;
+ u32 cmd_status_dword;
+ u16 origcmd, newcmd, status;
+
+ /* We do a single dword read to retrieve both command and status.
+ * Document assumptions that make this possible. */
+ BUILD_BUG_ON(PCI_COMMAND % 4);
+ BUILD_BUG_ON(PCI_COMMAND + 2 != PCI_STATUS);
+
+ spin_lock_irq(&gdev->lock);
+ pci_block_user_cfg_access(pdev);
+
+ /* Read both command and status registers in a single 32-bit operation.
+ * Note: we could cache the value for command and move the status read
+ * out of the lock if there was a way to get notified of user changes
+ * to command register through sysfs. Should be good for shared irqs. */
+ pci_read_config_dword(pdev, PCI_COMMAND, &cmd_status_dword);
+ origcmd = cmd_status_dword;
+ status = cmd_status_dword >> 16;
+
+ /* Check interrupt status register to see whether our device
+ * triggered the interrupt. */
+ if (!(status & PCI_STATUS_INTERRUPT))
+ goto done;
+
+ /* We triggered the interrupt, disable it. */
+ newcmd = origcmd | PCI_COMMAND_INTX_DISABLE;
+ if (newcmd != origcmd)
+ pci_write_config_word(pdev, PCI_COMMAND, newcmd);
+
+ /* UIO core will signal the user process. */
+ ret = IRQ_HANDLED;
+done:
+
+ pci_unblock_user_cfg_access(pdev);
+ spin_unlock_irq(&gdev->lock);
+ return ret;
+}
+
+/* Verify that the device supports Interrupt Disable bit in command register,
+ * per PCI 2.3, by flipping this bit and reading it back: this bit was readonly
+ * in PCI 2.2. */
+static int __devinit verify_pci_2_3(struct pci_dev *pdev)
+{
+ u16 orig, new;
+ int err = 0;
+
+ pci_block_user_cfg_access(pdev);
+ pci_read_config_word(pdev, PCI_COMMAND, &orig);
+ pci_write_config_word(pdev, PCI_COMMAND,
+ orig ^ PCI_COMMAND_INTX_DISABLE);
+ pci_read_config_word(pdev, PCI_COMMAND, &new);
+ /* There's no way to protect against
+ * hardware bugs or detect them reliably, but as long as we know
+ * what the value should be, let's go ahead and check it. */
+ if ((new ^ orig) & ~PCI_COMMAND_INTX_DISABLE) {
+ err = -EBUSY;
+ dev_err(&pdev->dev, "Command changed from 0x%x to 0x%x: "
+ "driver or HW bug?\n", orig, new);
+ goto err;
+ }
+ if (!((new ^ orig) & PCI_COMMAND_INTX_DISABLE)) {
+ dev_warn(&pdev->dev, "Device does not support "
+ "disabling interrupts: unable to bind.\n");
+ err = -ENODEV;
+ goto err;
+ }
+ /* Now restore the original value. */
+ pci_write_config_word(pdev, PCI_COMMAND, orig);
+err:
+ pci_unblock_user_cfg_access(pdev);
+ return err;
+}
+
+static int __devinit probe(struct pci_dev *pdev,
+ const struct pci_device_id *id)
+{
+ struct uio_pci_generic_dev *gdev;
+ int err;
+
+ if (!pdev->irq) {
+ dev_warn(&pdev->dev, "No IRQ assigned to device: "
+ "no support for interrupts?\n");
+ return -ENODEV;
+ }
+
+ err = pci_enable_device(pdev);
+ if (err) {
+ dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n",
+ __func__, err);
+ return err;
+ }
+
+ err = verify_pci_2_3(pdev);
+ if (err)
+ goto err_verify;
+
+ gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL);
+ if (!gdev) {
+ err = -ENOMEM;
+ goto err_alloc;
+ }
+
+ gdev->info.name = "uio_pci_generic";
+ gdev->info.version = DRIVER_VERSION;
+ gdev->info.irq = pdev->irq;
+ gdev->info.irq_flags = IRQF_SHARED;
+ gdev->info.handler = irqhandler;
+ gdev->pdev = pdev;
+ spin_lock_init(&gdev->lock);
+
+ if (uio_register_device(&pdev->dev, &gdev->info))
+ goto err_register;
+ pci_set_drvdata(pdev, gdev);
+
+ return 0;
+err_register:
+ kfree(gdev);
+err_alloc:
+err_verify:
+ pci_disable_device(pdev);
+ return err;
+}
+
+static void remove(struct pci_dev *pdev)
+{
+ struct uio_pci_generic_dev *gdev = pci_get_drvdata(pdev);
+
+ uio_unregister_device(&gdev->info);
+ pci_disable_device(pdev);
+ kfree(gdev);
+}
+
+static struct pci_driver driver = {
+ .name = "uio_pci_generic",
+ .id_table = NULL, /* only dynamic id's */
+ .probe = probe,
+ .remove = remove,
+};
+
+static int __init init(void)
+{
+ pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
+ return pci_register_driver(&driver);
+}
+
+static void __exit cleanup(void)
+{
+ pci_unregister_driver(&driver);
+}
+
+module_init(init);
+module_exit(cleanup);
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index fcaee42c7ac2a308676f30429dc98d02f9538225..dd0bed4f1cf00ffd00f5b2eace8103a25d606432 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -42,6 +42,7 @@
#define PCI_COMMAND_INTX_DISABLE 0x400 /* INTx Emulation Disable */
#define PCI_STATUS 0x06 /* 16 bits */
+#define PCI_STATUS_INTERRUPT 0x08 /* Interrupt status */
#define PCI_STATUS_CAP_LIST 0x10 /* Support Capability List */
#define PCI_STATUS_66MHZ 0x20 /* Support 66 Mhz PCI 2.1 bus */
#define PCI_STATUS_UDF 0x40 /* Support User Definable Features [obsolete] */