This patch adds an option to instantiate guest virtio-mmio devices
basing on a kernel command line (or module) parameter, for example:
virtio_mmio.devices=0x100 at 0x100b0000:48
Signed-off-by: Pawel Moll <pawel.moll at arm.com>
---
Hi Rusty,
As the param changes are in now, could you queue this
long-time-forgotten patch for 3.5?
Cheers!
Pawel
PS. Congratulations once again and see you in HK.
Documentation/kernel-parameters.txt | 17 ++++
drivers/virtio/Kconfig | 11 +++
drivers/virtio/virtio_mmio.c | 163 +++++++++++++++++++++++++++++++++++
3 files changed, 191 insertions(+), 0 deletions(-)
diff --git a/Documentation/kernel-parameters.txt
b/Documentation/kernel-parameters.txt
index c1601e5..8b35051 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -110,6 +110,7 @@ parameter is applicable:
USB USB support is enabled.
USBHID USB Human Interface Device support is enabled.
V4L Video For Linux support is enabled.
+ VMMIO Driver for memory mapped virtio devices is enabled.
VGA The VGA console has been enabled.
VT Virtual terminal support is enabled.
WDT Watchdog support is enabled.
@@ -2847,6 +2848,22 @@ bytes respectively. Such letter suffixes can also be
entirely omitted.
video= [FB] Frame buffer configuration
See Documentation/fb/modedb.txt.
+ virtio_mmio.device+ [VMMIO] Memory mapped virtio (platform) device.
+
+ <size>@<baseaddr>:<irq>[:<id>]
+ where:
+ <size> := size (can use standard suffixes
+ like K, M and G)
+ <baseaddr> := physical base address
+ <irq> := interrupt number (as passed to
+ request_irq())
+ <id> := (optional) platform device id
+ example:
+ virtio_mmio.device=1K at 0x100b0000:48:7
+
+ Can be used multiple times for multiple devices.
+
vga= [BOOT,X86-32] Select a particular video mode
See Documentation/x86/boot.txt and
Documentation/svga.txt.
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index 1a61939..f38b17a 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -46,4 +46,15 @@ config VIRTIO_BALLOON
If unsure, say N.
+config VIRTIO_MMIO_CMDLINE_DEVICES
+ bool "Memory mapped virtio devices parameter parsing"
+ depends on VIRTIO_MMIO
+ ---help---
+ Allow virtio-mmio devices instantiation via the kernel command line
+ or module parameters. Be aware that using incorrect parameters (base
+ address in particular) can crash your system - you have been warned.
+ See Documentation/kernel-parameters.txt for details.
+
+ If unsure, say 'N'.
+
endmenu
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 01d6dc2..453db0c 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -6,6 +6,50 @@
* This module allows virtio devices to be used over a virtual, memory mapped
* platform device.
*
+ * The guest device(s) may be instantiated in one of three equivalent ways:
+ *
+ * 1. Static platform device in board's code, eg.:
+ *
+ * static struct platform_device v2m_virtio_device = {
+ * .name = "virtio-mmio",
+ * .id = -1,
+ * .num_resources = 2,
+ * .resource = (struct resource []) {
+ * {
+ * .start = 0x1001e000,
+ * .end = 0x1001e0ff,
+ * .flags = IORESOURCE_MEM,
+ * }, {
+ * .start = 42 + 32,
+ * .end = 42 + 32,
+ * .flags = IORESOURCE_IRQ,
+ * },
+ * }
+ * };
+ *
+ * 2. Device Tree node, eg.:
+ *
+ * virtio_block at 1e000 {
+ * compatible = "virtio,mmio";
+ * reg = <0x1e000 0x100>;
+ * interrupts = <42>;
+ * }
+ *
+ * 3. Kernel module (or command line) parameter. Can be used more than once -
+ * one device will be created for each one. Syntax:
+ *
+ * [virtio_mmio.]device=<size>@<baseaddr>:<irq>[:<id>]
+ * where:
+ * <size> := size (can use standard suffixes like K, M or G)
+ * <baseaddr> := physical base address
+ * <irq> := interrupt number (as passed to request_irq())
+ * <id> := (optional) platform device id
+ * eg.:
+ * virtio_mmio.device=0x100 at 0x100b0000:48 \
+ * virtio_mmio.device=1K at 0x1001e000:74
+ *
+ *
+ *
* Registers layout (all 32-bit wide):
*
* offset d. name description
@@ -42,6 +86,8 @@
* See the COPYING file in the top-level directory.
*/
+#define pr_fmt(fmt) "virtio-mmio: " fmt
+
#include <linux/highmem.h>
#include <linux/interrupt.h>
#include <linux/io.h>
@@ -449,6 +495,122 @@ static int __devexit virtio_mmio_remove(struct
platform_device *pdev)
+/* Devices list parameter */
+
+#if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
+
+static struct device vm_cmdline_parent = {
+ .init_name = "virtio-mmio-cmdline",
+};
+
+static int vm_cmdline_parent_registered;
+static int vm_cmdline_id;
+
+static int vm_cmdline_set(const char *device,
+ const struct kernel_param *kp)
+{
+ int err;
+ struct resource resources[2] = {};
+ char *str;
+ long long int base;
+ int processed, consumed = 0;
+ struct platform_device *pdev;
+
+ resources[0].flags = IORESOURCE_MEM;
+ resources[1].flags = IORESOURCE_IRQ;
+
+ resources[0].end = memparse(device, &str) - 1;
+
+ processed = sscanf(str, "@%lli:%u%n:%d%n",
+ &base, &resources[1].start, &consumed,
+ &vm_cmdline_id, &consumed);
+
+ if (processed < 2 || processed > 3 || str[consumed])
+ return -EINVAL;
+
+ resources[0].start = base;
+ resources[0].end += base;
+ resources[1].end = resources[1].start;
+
+ if (!vm_cmdline_parent_registered) {
+ err = device_register(&vm_cmdline_parent);
+ if (err) {
+ pr_err("Failed to register parent device!\n");
+ return err;
+ }
+ vm_cmdline_parent_registered = 1;
+ }
+
+ pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ
%d.\n",
+ vm_cmdline_id,
+ (unsigned long long)resources[0].start,
+ (unsigned long long)resources[0].end,
+ (int)resources[1].start);
+
+ pdev = platform_device_register_resndata(&vm_cmdline_parent,
+ "virtio-mmio", vm_cmdline_id++,
+ resources, ARRAY_SIZE(resources), NULL, 0);
+ if (IS_ERR(pdev))
+ return PTR_ERR(pdev);
+
+ return 0;
+}
+
+static int vm_cmdline_get_device(struct device *dev, void *data)
+{
+ char *buffer = data;
+ unsigned int len = strlen(buffer);
+ struct platform_device *pdev = to_platform_device(dev);
+
+ snprintf(buffer + len, PAGE_SIZE - len, "0x%llx at
0x%llx:%llu:%d\n",
+ pdev->resource[0].end - pdev->resource[0].start + 1ULL,
+ (unsigned long long)pdev->resource[0].start,
+ (unsigned long long)pdev->resource[1].start,
+ pdev->id);
+ return 0;
+}
+
+static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
+{
+ buffer[0] = '\0';
+ device_for_each_child(&vm_cmdline_parent, buffer,
+ vm_cmdline_get_device);
+ return strlen(buffer) + 1;
+}
+
+static struct kernel_param_ops vm_cmdline_param_ops = {
+ .set = vm_cmdline_set,
+ .get = vm_cmdline_get,
+};
+
+device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
+
+static int vm_unregister_cmdline_device(struct device *dev,
+ void *data)
+{
+ platform_device_unregister(to_platform_device(dev));
+
+ return 0;
+}
+
+static void vm_unregister_cmdline_devices(void)
+{
+ if (vm_cmdline_parent_registered) {
+ device_for_each_child(&vm_cmdline_parent, NULL,
+ vm_unregister_cmdline_device);
+ device_unregister(&vm_cmdline_parent);
+ vm_cmdline_parent_registered = 0;
+ }
+}
+
+#else
+
+static void vm_unregister_cmdline_devices(void)
+{
+}
+
+#endif
+
/* Platform driver */
static struct of_device_id virtio_mmio_match[] = {
@@ -475,6 +637,7 @@ static int __init virtio_mmio_init(void)
static void __exit virtio_mmio_exit(void)
{
platform_driver_unregister(&virtio_mmio_driver);
+ vm_unregister_cmdline_devices();
}
module_init(virtio_mmio_init);
--
1.7.5.4