virtio-mmio: Devices parameter parsing (81a054ce) · Commits · 戴 / test

Documentation/kernel-parameters.txt

+17 −0

Original line number	Diff line number	Diff line
		@@ -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@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.

drivers/virtio/Kconfig

+11 −0

Original line number	Diff line number	Diff line
		@@ -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

drivers/virtio/virtio_mmio.c

+163 −0

Original line number	Diff line number	Diff line
		@@ -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@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@0x100b0000:48 \
		* virtio_mmio.device=1K@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@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);

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