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@0x100b0000:48,1K@0x1001e000:74
Signed-off-by: Pawel Moll <pawel.moll@xxxxxxx>
---
drivers/virtio/Kconfig | 31 +++++++
drivers/virtio/virtio_mmio.c | 181 +++++++++++++++++++++++++++++++++++++++++-
2 files changed, 211 insertions(+), 1 deletions(-)
Hi Rusty,
This version adds the "first_id" parameter I mentioned yesterday,
but still using single charp parameter instead of the _cb version.
And unless you are really (_really_) against it, I'd rather see
this variant.
Cheers!
Paweł
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index 816ed08..00f2c82 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -46,4 +46,35 @@ 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 parameter. Be aware that using incorrect parameters (base
+ address in particular) can crash your system - you have been warned.
+
+ The format for the parameter is as follows:
+
+ [virtio_mmio.]devices=<device>[<delim><device>]
+
+ where:
+ <device> := <size>@<baseaddr>:<irq>
+ <delim> := ',' or ';'
+ <size> := size (can use standard suffixes like K or M)
+ <baseaddr> := physical base address
+ <irq> := interrupt number (as passed to request_irq())
+
+ Example kernel command line parameter:
+
+ virtio_mmio.devices=0x100@0x100b0000:48,1K@0x1001e000:74
+
+ This will register platform devices virtio_mmio.<id>, where <id>
+ values are consecutive integer numbers starting from 0 by default.
+ The first id value can be changed with "first_id" parameter:
+
+ [virtio_mmio.]first_id=<id>
+
+ If unsure, say 'N'.
+
endmenu
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index acc5e43..05b39c1 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -6,6 +6,55 @@
* 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@1e000 {
+ * compatible = "virtio,mmio";
+ * reg = <0x1e000 0x100>;
+ * interrupts = <42>;
+ * }
+ *
+ * 3. Kernel module (or command line) parameter:
+ *
+ * [virtio_mmio.]devices=<device>[<delim><device>]
+ * where:
+ * <device> := <size>@<baseaddr>:<irq>
+ * <delim> := ',' or ';'
+ * <size> := size (can use standard suffixes like K or M)
+ * <baseaddr> := physical base address
+ * <irq> := interrupt number (as passed to request_irq())
+ * eg.:
+ * virtio_mmio.devices=0x100@0x100b0000:48,1K@0x1001e000:74
+ *
+ * This will register platform devices virtio_mmio.<id>, where <id>
+ * values are consecutive integer numbers starting from 0 by default.
+ * The first id value can be changed with "first_id" parameter:
+ *
+ * [virtio_mmio.]first_id=<id>
+ *
+ *
+ *
* Registers layout (all 32-bit wide):
*
* offset d. name description
@@ -42,6 +91,8 @@
* 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>
@@ -443,6 +494,130 @@ static int __devexit virtio_mmio_remove(struct platform_device *pdev)
+/* Devices list parameter */
+
+#if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
+
+static char *virtio_mmio_cmdline_devices;
+module_param_named(devices, virtio_mmio_cmdline_devices, charp, 0);
+
+static int virtio_mmio_cmdline_id;
+module_param_named(first_id, virtio_mmio_cmdline_id, int, 0);
+
+static struct device virtio_mmio_cmdline_parent = {
+ .init_name = "virtio-mmio-cmdline",
+};
+
+static int virtio_mmio_register_cmdline_devices(void)
+{
+ int err;
+ char *device;
+ char *token = NULL;
+
+ err = device_register(&virtio_mmio_cmdline_parent);
+ if (err) {
+ pr_err("Failed to register %s!\n",
+ virtio_mmio_cmdline_parent.init_name);
+ return err;
+ }
+
+ /* Split colon-or-semicolon-separated devices */
+ while ((device = strsep(&virtio_mmio_cmdline_devices, ",;")) != NULL) {
+ struct resource resources[] = {
+ {
+ .flags = IORESOURCE_IRQ,
+ }, {
+ .flags = IORESOURCE_MEM,
+ }
+ };
+ char *size, *base;
+ unsigned long long val;
+
+ if (!*device)
+ continue;
+
+ kfree(token);
+ token = kstrdup(device, GFP_KERNEL);
+
+ /* Split memory and IRQ resources */
+ base = strsep(&token, ":");
+ if (base == token || !token || !*token) {
+ pr_err("No IRQ in '%s'!\n", device);
+ continue;
+ }
+
+ /* Get IRQ */
+ if (kstrtoull(token, 0, &val) != 0) {
+ pr_err("Wrong IRQ in '%s'!\n", device);
+ continue;
+ }
+ resources[0].start = val;
+ resources[0].end = val;
+
+ /* Split base address and size */
+ size = strsep(&base, "@");
+ if (size == base || !base || !*base) {
+ pr_err("No base in '%s'!\n", device);
+ continue;
+ }
+
+ /* Get base address */
+ if (kstrtoull(base, 0, &val) != 0) {
+ pr_err("Wrong base in '%s'!\n", device);
+ continue;
+ }
+ resources[1].start = val;
+ resources[1].end = val;
+
+ /* Get size */
+ resources[1].end += memparse(size, &token) - 1;
+ if (size == token || *token) {
+ pr_err("Wrong size in '%s'!\n", device);
+ continue;
+ }
+
+ pr_info("Registering device %d at 0x%x-0x%x, IRQ %u.\n",
+ virtio_mmio_cmdline_id, resources[1].start,
+ resources[1].end, resources[0].start);
+
+ platform_device_register_resndata(&virtio_mmio_cmdline_parent,
+ "virtio-mmio", virtio_mmio_cmdline_id++,
+ resources, ARRAY_SIZE(resources), NULL, 0);
+ }
+
+ kfree(token);
+
+ return 0;
+}
+
+static int virtio_mmio_unregister_cmdline_device(struct device *dev,
+ void *data)
+{
+ platform_device_unregister(to_platform_device(dev));
+
+ return 0;
+}
+
+static void virtio_mmio_unregister_cmdline_devices(void)
+{
+ device_for_each_child(&virtio_mmio_cmdline_parent, NULL,
+ virtio_mmio_unregister_cmdline_device);
+ device_unregister(&virtio_mmio_cmdline_parent);
+}
+
+#else
+
+static int virtio_mmio_register_cmdline_devices(void)
+{
+ return 0;
+}
+
+static void virtio_mmio_unregister_cmdline_devices(void)
+{
+}
+
+#endif
+
/* Platform driver */
static struct of_device_id virtio_mmio_match[] = {
@@ -463,11 +638,15 @@ static struct platform_driver virtio_mmio_driver = {
static int __init virtio_mmio_init(void)
{
- return platform_driver_register(&virtio_mmio_driver);
+ int err = virtio_mmio_register_cmdline_devices();
+
+ return err ? err : platform_driver_register(&virtio_mmio_driver);
}
static void __exit virtio_mmio_exit(void)
{
+ virtio_mmio_unregister_cmdline_devices();
+
platform_driver_unregister(&virtio_mmio_driver);
}
--
1.6.3.3
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