virtio-mmio: Devices parameter parsing

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 Signed-off-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio-mmio: Devices parameter parsing
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 Signed-off-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Pawel Moll · Rusty Russell
1 parent f65ca1dc6a
Showing 3 changed files with 191 additions and 0 deletions Side-by-side Diff
Documentation/kernel-parameters.txt
drivers/virtio/Kconfig
drivers/virtio/virtio_mmio.c
@@ -110,6 +110,7 @@
 	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.
@@ -2846,6 +2847,22 @@
  
 	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
@@ -46,5 +46,16 @@
  
  	 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
@@ -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 @@
  
  
  
+/* 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 void __exit virtio_mmio_exit(void)
 {
 	platform_driver_unregister(&virtio_mmio_driver);
+	vm_unregister_cmdline_devices();
 }
  
 module_init(virtio_mmio_init);
...	...	@@ -110,6 +110,7 @@
110	110	USB USB support is enabled.
111	111	USBHID USB Human Interface Device support is enabled.
112	112	V4L Video For Linux support is enabled.
	113	+ VMMIO Driver for memory mapped virtio devices is enabled.
113	114	VGA The VGA console has been enabled.
114	115	VT Virtual terminal support is enabled.
115	116	WDT Watchdog support is enabled.
...	...	@@ -2846,6 +2847,22 @@
2846	2847
2847	2848	video= [FB] Frame buffer configuration
2848	2849	See Documentation/fb/modedb.txt.
	2850	+
	2851	+ virtio_mmio.device=
	2852	+ [VMMIO] Memory mapped virtio (platform) device.
	2853	+
	2854	+ <size>@<baseaddr>:<irq>[:<id>]
	2855	+ where:
	2856	+ <size> := size (can use standard suffixes
	2857	+ like K, M and G)
	2858	+ <baseaddr> := physical base address
	2859	+ <irq> := interrupt number (as passed to
	2860	+ request_irq())
	2861	+ <id> := (optional) platform device id
	2862	+ example:
	2863	+ virtio_mmio.device=1K@0x100b0000:48:7
	2864	+
	2865	+ Can be used multiple times for multiple devices.
2849	2866
2850	2867	vga= [BOOT,X86-32] Select a particular video mode
2851	2868	See Documentation/x86/boot.txt and
...	...	@@ -46,5 +46,16 @@
46	46
47	47	If unsure, say N.
48	48
	49	+config VIRTIO_MMIO_CMDLINE_DEVICES
	50	+ bool "Memory mapped virtio devices parameter parsing"
	51	+ depends on VIRTIO_MMIO
	52	+ ---help---
	53	+ Allow virtio-mmio devices instantiation via the kernel command line
	54	+ or module parameters. Be aware that using incorrect parameters (base
	55	+ address in particular) can crash your system - you have been warned.
	56	+ See Documentation/kernel-parameters.txt for details.
	57	+
	58	+ If unsure, say 'N'.
	59	+
49	60	endmenu
...	...	@@ -6,6 +6,50 @@
6	6	* This module allows virtio devices to be used over a virtual, memory mapped
7	7	* platform device.
8	8	*
	9	+ * The guest device(s) may be instantiated in one of three equivalent ways:
	10	+ *
	11	+ * 1. Static platform device in board's code, eg.:
	12	+ *
	13	+ * static struct platform_device v2m_virtio_device = {
	14	+ * .name = "virtio-mmio",
	15	+ * .id = -1,
	16	+ * .num_resources = 2,
	17	+ * .resource = (struct resource []) {
	18	+ * {
	19	+ * .start = 0x1001e000,
	20	+ * .end = 0x1001e0ff,
	21	+ * .flags = IORESOURCE_MEM,
	22	+ * }, {
	23	+ * .start = 42 + 32,
	24	+ * .end = 42 + 32,
	25	+ * .flags = IORESOURCE_IRQ,
	26	+ * },
	27	+ * }
	28	+ * };
	29	+ *
	30	+ * 2. Device Tree node, eg.:
	31	+ *
	32	+ * virtio_block@1e000 {
	33	+ * compatible = "virtio,mmio";
	34	+ * reg = <0x1e000 0x100>;
	35	+ * interrupts = <42>;
	36	+ * }
	37	+ *
	38	+ * 3. Kernel module (or command line) parameter. Can be used more than once -
	39	+ * one device will be created for each one. Syntax:
	40	+ *
	41	+ * [virtio_mmio.]device=<size>@<baseaddr>:<irq>[:<id>]
	42	+ * where:
	43	+ * <size> := size (can use standard suffixes like K, M or G)
	44	+ * <baseaddr> := physical base address
	45	+ * <irq> := interrupt number (as passed to request_irq())
	46	+ * <id> := (optional) platform device id
	47	+ * eg.:
	48	+ * virtio_mmio.device=0x100@0x100b0000:48 \
	49	+ * virtio_mmio.device=1K@0x1001e000:74
	50	+ *
	51	+ *
	52	+ *
9	53	* Registers layout (all 32-bit wide):
10	54	*
11	55	* offset d. name description
...	...	@@ -42,6 +86,8 @@
42	86	* See the COPYING file in the top-level directory.
43	87	*/
44	88
	89	+#define pr_fmt(fmt) "virtio-mmio: " fmt
	90	+
45	91	#include <linux/highmem.h>
46	92	#include <linux/interrupt.h>
47	93	#include <linux/io.h>
...	...	@@ -449,6 +495,122 @@
449	495
450	496
451	497
	498	+/* Devices list parameter */
	499	+
	500	+#if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
	501	+
	502	+static struct device vm_cmdline_parent = {
	503	+ .init_name = "virtio-mmio-cmdline",
	504	+};
	505	+
	506	+static int vm_cmdline_parent_registered;
	507	+static int vm_cmdline_id;
	508	+
	509	+static int vm_cmdline_set(const char *device,
	510	+ const struct kernel_param *kp)
	511	+{
	512	+ int err;
	513	+ struct resource resources[2] = {};
	514	+ char *str;
	515	+ long long int base;
	516	+ int processed, consumed = 0;
	517	+ struct platform_device *pdev;
	518	+
	519	+ resources[0].flags = IORESOURCE_MEM;
	520	+ resources[1].flags = IORESOURCE_IRQ;
	521	+
	522	+ resources[0].end = memparse(device, &str) - 1;
	523	+
	524	+ processed = sscanf(str, "@%lli:%u%n:%d%n",
	525	+ &base, &resources[1].start, &consumed,
	526	+ &vm_cmdline_id, &consumed);
	527	+
	528	+ if (processed < 2 \|\| processed > 3 \|\| str[consumed])
	529	+ return -EINVAL;
	530	+
	531	+ resources[0].start = base;
	532	+ resources[0].end += base;
	533	+ resources[1].end = resources[1].start;
	534	+
	535	+ if (!vm_cmdline_parent_registered) {
	536	+ err = device_register(&vm_cmdline_parent);
	537	+ if (err) {
	538	+ pr_err("Failed to register parent device!\n");
	539	+ return err;
	540	+ }
	541	+ vm_cmdline_parent_registered = 1;
	542	+ }
	543	+
	544	+ pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
	545	+ vm_cmdline_id,
	546	+ (unsigned long long)resources[0].start,
	547	+ (unsigned long long)resources[0].end,
	548	+ (int)resources[1].start);
	549	+
	550	+ pdev = platform_device_register_resndata(&vm_cmdline_parent,
	551	+ "virtio-mmio", vm_cmdline_id++,
	552	+ resources, ARRAY_SIZE(resources), NULL, 0);
	553	+ if (IS_ERR(pdev))
	554	+ return PTR_ERR(pdev);
	555	+
	556	+ return 0;
	557	+}
	558	+
	559	+static int vm_cmdline_get_device(struct device dev, void data)
	560	+{
	561	+ char *buffer = data;
	562	+ unsigned int len = strlen(buffer);
	563	+ struct platform_device *pdev = to_platform_device(dev);
	564	+
	565	+ snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
	566	+ pdev->resource[0].end - pdev->resource[0].start + 1ULL,
	567	+ (unsigned long long)pdev->resource[0].start,
	568	+ (unsigned long long)pdev->resource[1].start,
	569	+ pdev->id);
	570	+ return 0;
	571	+}
	572	+
	573	+static int vm_cmdline_get(char buffer, const struct kernel_param kp)
	574	+{
	575	+ buffer[0] = '\0';
	576	+ device_for_each_child(&vm_cmdline_parent, buffer,
	577	+ vm_cmdline_get_device);
	578	+ return strlen(buffer) + 1;
	579	+}
	580	+
	581	+static struct kernel_param_ops vm_cmdline_param_ops = {
	582	+ .set = vm_cmdline_set,
	583	+ .get = vm_cmdline_get,
	584	+};
	585	+
	586	+device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
	587	+
	588	+static int vm_unregister_cmdline_device(struct device *dev,
	589	+ void *data)
	590	+{
	591	+ platform_device_unregister(to_platform_device(dev));
	592	+
	593	+ return 0;
	594	+}
	595	+
	596	+static void vm_unregister_cmdline_devices(void)
	597	+{
	598	+ if (vm_cmdline_parent_registered) {
	599	+ device_for_each_child(&vm_cmdline_parent, NULL,
	600	+ vm_unregister_cmdline_device);
	601	+ device_unregister(&vm_cmdline_parent);
	602	+ vm_cmdline_parent_registered = 0;
	603	+ }
	604	+}
	605	+
	606	+#else
	607	+
	608	+static void vm_unregister_cmdline_devices(void)
	609	+{
	610	+}
	611	+
	612	+#endif
	613	+
452	614	/* Platform driver */
453	615
454	616	static struct of_device_id virtio_mmio_match[] = {
...	...	@@ -475,6 +637,7 @@
475	637	static void __exit virtio_mmio_exit(void)
476	638	{
477	639	platform_driver_unregister(&virtio_mmio_driver);
	640	+ vm_unregister_cmdline_devices();
478	641	}
479	642
480	643	module_init(virtio_mmio_init);