This patch adds a driver for my shared memory PCI device using the uio_pci
interface. The driver has three memory regions. The first memory region is for
device registers for sending interrupts. The second BAR is for receiving MSI-X
interrupts and the third memory region maps the shared memory. The device only
exports the first and third memory regions to userspace.
This driver supports MSI-X and regular pin interrupts. Currently, the number
of MSI vectors is set to 1 but it could easily be increased. If MSI is not
available, then regular interrupts will be used.
---
drivers/uio/Kconfig | 8 ++
drivers/uio/Makefile | 1 +
drivers/uio/uio_ivshmem.c | 252 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 261 insertions(+), 0 deletions(-)
create mode 100644 drivers/uio/uio_ivshmem.c
diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
index 1da73ec..b92cded 100644
--- a/drivers/uio/Kconfig
+++ b/drivers/uio/Kconfig
@@ -74,6 +74,14 @@ config UIO_SERCOS3
If you compile this as a module, it will be called uio_sercos3.
+config UIO_IVSHMEM
+ tristate "KVM shared memory PCI driver"
+ default n
+ help
+ Userspace I/O interface for the KVM shared memory device. This
+ driver will make available two memory regions, the first is
+ registers and the second is a region for sharing between VMs.
+
config UIO_PCI_GENERIC
tristate "Generic driver for PCI 2.3 and PCI Express cards"
depends on PCI
diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile
index 18fd818..25c1ca5 100644
--- a/drivers/uio/Makefile
+++ b/drivers/uio/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_UIO_AEC) += uio_aec.o
obj-$(CONFIG_UIO_SERCOS3) += uio_sercos3.o
obj-$(CONFIG_UIO_PCI_GENERIC) += uio_pci_generic.o
obj-$(CONFIG_UIO_NETX) += uio_netx.o
+obj-$(CONFIG_UIO_IVSHMEM) += uio_ivshmem.o
diff --git a/drivers/uio/uio_ivshmem.c b/drivers/uio/uio_ivshmem.c
new file mode 100644
index 0000000..95be1e0
--- /dev/null
+++ b/drivers/uio/uio_ivshmem.c
@@ -0,0 +1,252 @@
+/*
+ * UIO IVShmem Driver
+ *
+ * (C) 2009 Cam Macdonell
+ * based on Hilscher CIF card driver (C) 2007 Hans J. Koch <hjk@xxxxxxxxxxxxx>
+ *
+ * Licensed under GPL version 2 only.
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/uio_driver.h>
+
+#include <asm/io.h>
+
+#define IntrStatus 0x04
+#define IntrMask 0x00
+
+struct ivshmem_info {
+ struct uio_info *uio;
+ struct pci_dev *dev;
+ char (*msix_names)[256];
+ struct msix_entry *msix_entries;
+ int nvectors;
+};
+
+static irqreturn_t ivshmem_handler(int irq, struct uio_info *dev_info)
+{
+
+ void __iomem *plx_intscr = dev_info->mem[0].internal_addr
+ + IntrStatus;
+ u32 val;
+
+ val = readl(plx_intscr);
+ if (val == 0)
+ return IRQ_NONE;
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t ivshmem_msix_handler(int irq, void *opaque)
+{
+
+ struct uio_info * dev_info = (struct uio_info *) opaque;
+
+ /* we have to do this explicitly when using MSI-X */
+ uio_event_notify(dev_info);
+ return IRQ_HANDLED;
+}
+
+static void free_msix_vectors(struct ivshmem_info *ivs_info,
+ const int max_vector)
+{
+ int i;
+
+ for (i = 0; i < max_vector; i++)
+ free_irq(ivs_info->msix_entries[i].vector, ivs_info->uio);
+}
+
+static int request_msix_vectors(struct ivshmem_info *ivs_info, int nvectors)
+{
+ int i, err;
+ const char *name = "ivshmem";
+
+ ivs_info->nvectors = nvectors;
+
+ ivs_info->msix_entries = kmalloc(nvectors * sizeof *
+ ivs_info->msix_entries,
+ GFP_KERNEL);
+ if (ivs_info->msix_entries == NULL)
+ return -ENOSPC;
+
+ ivs_info->msix_names = kmalloc(nvectors * sizeof *ivs_info->msix_names,
+ GFP_KERNEL);
+ if (ivs_info->msix_names == NULL) {
+ kfree(ivs_info->msix_entries);
+ return -ENOSPC;
+ }
+
+ for (i = 0; i < nvectors; ++i)
+ ivs_info->msix_entries[i].entry = i;
+
+ err = pci_enable_msix(ivs_info->dev, ivs_info->msix_entries,
+ ivs_info->nvectors);
+ if (err > 0) {
+ ivs_info->nvectors = err; /* msi-x positive error code
+ returns the number available*/
+ err = pci_enable_msix(ivs_info->dev, ivs_info->msix_entries,
+ ivs_info->nvectors);
+ if (err) {
+ printk(KERN_INFO "no MSI (%d). Back to INTx.\n", err);
+ goto error;
+ }
+ }
+
+ if (err)
+ goto error;
+
+ for (i = 0; i < ivs_info->nvectors; i++) {
+
+ snprintf(ivs_info->msix_names[i], sizeof *ivs_info->msix_names,
+ "%s-config", name);
+
+ err = request_irq(ivs_info->msix_entries[i].vector,
+ ivshmem_msix_handler, 0,
+ ivs_info->msix_names[i], ivs_info->uio);
+
+ if (err) {
+ free_msix_vectors(ivs_info, i - 1);
+ goto error;
+ }
+
+ }
+
+ return 0;
+error:
+ kfree(ivs_info->msix_entries);
+ kfree(ivs_info->msix_names);
+ return err;
+
+}
+
+static int __devinit ivshmem_pci_probe(struct pci_dev *dev,
+ const struct pci_device_id *id)
+{
+ struct uio_info *info;
+ struct ivshmem_info * ivshmem_info;
+ int nvectors = 1;
+
+ info = kzalloc(sizeof(struct uio_info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ ivshmem_info = kzalloc(sizeof(struct ivshmem_info), GFP_KERNEL);
+ if (!ivshmem_info) {
+ kfree(info);
+ return -ENOMEM;
+ }
+
+ if (pci_enable_device(dev))
+ goto out_free;
+
+ if (pci_request_regions(dev, "ivshmem"))
+ goto out_disable;
+
+ info->mem[0].addr = pci_resource_start(dev, 0);
+ if (!info->mem[0].addr)
+ goto out_release;
+
+ info->mem[0].size = pci_resource_len(dev, 0);
+ info->mem[0].internal_addr = pci_ioremap_bar(dev, 0);
+ if (!info->mem[0].internal_addr) {
+ goto out_release;
+ }
+
+ info->mem[0].memtype = UIO_MEM_PHYS;
+
+ info->mem[1].addr = pci_resource_start(dev, 2);
+ if (!info->mem[1].addr)
+ goto out_unmap;
+ info->mem[1].internal_addr = pci_ioremap_bar(dev, 2);
+ if (!info->mem[1].internal_addr)
+ goto out_unmap;
+
+ info->mem[1].size = pci_resource_len(dev, 2);
+ info->mem[1].memtype = UIO_MEM_PHYS;
+
+ ivshmem_info->uio = info;
+ ivshmem_info->dev = dev;
+
+ if (request_msix_vectors(ivshmem_info, nvectors) != 0) {
+ printk(KERN_INFO "regular IRQs\n");
+ info->irq = dev->irq;
+ info->irq_flags = IRQF_SHARED;
+ info->handler = ivshmem_handler;
+ writel(0xffffffff, info->mem[0].internal_addr + IntrMask);
+ } else {
+ printk(KERN_INFO "MSI-X enabled\n");
+ info->irq = -1;
+ }
+
+ info->name = "ivshmem";
+ info->version = "0.0.1";
+
+ if (uio_register_device(&dev->dev, info))
+ goto out_unmap2;
+
+ pci_set_drvdata(dev, info);
+
+
+ return 0;
+out_unmap2:
+ iounmap(info->mem[2].internal_addr);
+out_unmap:
+ iounmap(info->mem[0].internal_addr);
+out_release:
+ pci_release_regions(dev);
+out_disable:
+ pci_disable_device(dev);
+out_free:
+ kfree (info);
+ return -ENODEV;
+}
+
+static void ivshmem_pci_remove(struct pci_dev *dev)
+{
+ struct uio_info *info = pci_get_drvdata(dev);
+
+ uio_unregister_device(info);
+ pci_release_regions(dev);
+ pci_disable_device(dev);
+ pci_set_drvdata(dev, NULL);
+ iounmap(info->mem[0].internal_addr);
+
+ kfree (info);
+}
+
+static struct pci_device_id ivshmem_pci_ids[] __devinitdata = {
+ {
+ .vendor = 0x1af4,
+ .device = 0x1110,
+ .subvendor = PCI_ANY_ID,
+ .subdevice = PCI_ANY_ID,
+ },
+ { 0, }
+};
+
+static struct pci_driver ivshmem_pci_driver = {
+ .name = "uio_ivshmem",
+ .id_table = ivshmem_pci_ids,
+ .probe = ivshmem_pci_probe,
+ .remove = ivshmem_pci_remove,
+};
+
+static int __init ivshmem_init_module(void)
+{
+ return pci_register_driver(&ivshmem_pci_driver);
+}
+
+static void __exit ivshmem_exit_module(void)
+{
+ pci_unregister_driver(&ivshmem_pci_driver);
+}
+
+module_init(ivshmem_init_module);
+module_exit(ivshmem_exit_module);
+
+MODULE_DEVICE_TABLE(pci, ivshmem_pci_ids);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Cam Macdonell");
--
1.6.3.2.198.g6096d
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