drivers/misc/aspeed-lpc-ctrl.c - arm/linux - Git at Google

 /*
  * Copyright 2017 IBM Corporation
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */

 #include <linux/mfd/syscon.h>
 #include <linux/miscdevice.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
 #include <linux/poll.h>
 #include <linux/regmap.h>

 #include <linux/aspeed-lpc-ctrl.h>

 #define DEVICE_NAME	"aspeed-lpc-ctrl"

 #define HICR7 0x8
 #define HICR8 0xc

 struct aspeed_lpc_ctrl {
 	struct miscdevice	miscdev;
 	struct regmap		*regmap;
 	phys_addr_t		mem_base;
 	resource_size_t		mem_size;
 	u32		pnor_size;
 	u32		pnor_base;
 };

 static struct aspeed_lpc_ctrl *file_aspeed_lpc_ctrl(struct file *file)
 {
 	return container_of(file->private_data, struct aspeed_lpc_ctrl,
 			miscdev);
 }

 static int aspeed_lpc_ctrl_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
 	unsigned long vsize = vma->vm_end - vma->vm_start;
 	pgprot_t prot = vma->vm_page_prot;

 	if (vma->vm_pgoff + vsize > lpc_ctrl->mem_base + lpc_ctrl->mem_size)
 		return -EINVAL;

 	/* ast2400/2500 AHB accesses are not cache coherent */
 	prot = pgprot_noncached(prot);

 	if (remap_pfn_range(vma, vma->vm_start,
 		(lpc_ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff,
 		vsize, prot))
 		return -EAGAIN;

 	return 0;
 }

 static long aspeed_lpc_ctrl_ioctl(struct file *file, unsigned int cmd,
 		unsigned long param)
 {
 	struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
 	void __user *p = (void __user *)param;
 	struct aspeed_lpc_ctrl_mapping map;
 	u32 addr;
 	u32 size;
 	long rc;

 	if (copy_from_user(&map, p, sizeof(map)))
 		return -EFAULT;

 	if (map.flags != 0)
 		return -EINVAL;

 	switch (cmd) {
 	case ASPEED_LPC_CTRL_IOCTL_GET_SIZE:
 		/* The flash windows don't report their size */
 		if (map.window_type != ASPEED_LPC_CTRL_WINDOW_MEMORY)
 			return -EINVAL;

 		/* Support more than one window id in the future */
 		if (map.window_id != 0)
 			return -EINVAL;

 		map.size = lpc_ctrl->mem_size;

 		return copy_to_user(p, &map, sizeof(map)) ? -EFAULT : 0;
 	case ASPEED_LPC_CTRL_IOCTL_MAP:

 		/*
 		 * The top half of HICR7 is the MSB of the BMC address of the
 		 * mapping.
 		 * The bottom half of HICR7 is the MSB of the HOST LPC
 		 * firmware space address of the mapping.
 		 *
 		 * The 1 bits in the top of half of HICR8 represent the bits
 		 * (in the requested address) that should be ignored and
 		 * replaced with those from the top half of HICR7.
 		 * The 1 bits in the bottom half of HICR8 represent the bits
 		 * (in the requested address) that should be kept and pass
 		 * into the BMC address space.
 		 */

 		/*
 		 * It doesn't make sense to talk about a size or offset with
 		 * low 16 bits set. Both HICR7 and HICR8 talk about the top 16
 		 * bits of addresses and sizes.
 		 */

 		if ((map.size & 0x0000ffff) || (map.offset & 0x0000ffff))
 			return -EINVAL;

 		/*
 		 * Because of the way the masks work in HICR8 offset has to
 		 * be a multiple of size.
 		 */
 		if (map.offset & (map.size - 1))
 			return -EINVAL;

 		if (map.window_type == ASPEED_LPC_CTRL_WINDOW_FLASH) {
 			addr = lpc_ctrl->pnor_base;
 			size = lpc_ctrl->pnor_size;
 		} else if (map.window_type == ASPEED_LPC_CTRL_WINDOW_MEMORY) {
 			addr = lpc_ctrl->mem_base;
 			size = lpc_ctrl->mem_size;
 		} else {
 			return -EINVAL;
 		}

 		/* Check overflow first! */
 		if (map.offset + map.size < map.offset ||
 			map.offset + map.size > size)
 			return -EINVAL;

 		if (map.size == 0 || map.size > size)
 			return -EINVAL;

 		addr += map.offset;

 		/*
 		 * addr (host lpc address) is safe regardless of values. This
 		 * simply changes the address the host has to request on its
 		 * side of the LPC bus. This cannot impact the hosts own
 		 * memory space by surprise as LPC specific accessors are
 		 * required. The only strange thing that could be done is
 		 * setting the lower 16 bits but the shift takes care of that.
 		 */

 		rc = regmap_write(lpc_ctrl->regmap, HICR7,
 				(addr | (map.addr >> 16)));
 		if (rc)
 			return rc;

 		return regmap_write(lpc_ctrl->regmap, HICR8,
 			(~(map.size - 1)) | ((map.size >> 16) - 1));
 	}

 	return -EINVAL;
 }

 static const struct file_operations aspeed_lpc_ctrl_fops = {
 	.owner		= THIS_MODULE,
 	.mmap		= aspeed_lpc_ctrl_mmap,
 	.unlocked_ioctl	= aspeed_lpc_ctrl_ioctl,
 };

 static int aspeed_lpc_ctrl_probe(struct platform_device *pdev)
 {
 	struct aspeed_lpc_ctrl *lpc_ctrl;
 	struct device_node *node;
 	struct resource resm;
 	struct device *dev;
 	int rc;

 	dev = &pdev->dev;

 	lpc_ctrl = devm_kzalloc(dev, sizeof(*lpc_ctrl), GFP_KERNEL);
 	if (!lpc_ctrl)
 		return -ENOMEM;

 	node = of_parse_phandle(dev->of_node, "flash", 0);
 	if (!node) {
 		dev_err(dev, "Didn't find host pnor flash node\n");
 		return -ENODEV;
 	}

 	rc = of_address_to_resource(node, 1, &resm);
 	of_node_put(node);
 	if (rc) {
 		dev_err(dev, "Couldn't address to resource for flash\n");
 		return rc;
 	}

 	lpc_ctrl->pnor_size = resource_size(&resm);
 	lpc_ctrl->pnor_base = resm.start;

 	dev_set_drvdata(&pdev->dev, lpc_ctrl);

 	node = of_parse_phandle(dev->of_node, "memory-region", 0);
 	if (!node) {
 		dev_err(dev, "Didn't find reserved memory\n");
 		return -EINVAL;
 	}

 	rc = of_address_to_resource(node, 0, &resm);
 	of_node_put(node);
 	if (rc) {
 		dev_err(dev, "Couldn't address to resource for reserved memory\n");
 		return -ENOMEM;
 	}

 	lpc_ctrl->mem_size = resource_size(&resm);
 	lpc_ctrl->mem_base = resm.start;

 	lpc_ctrl->regmap = syscon_node_to_regmap(
 			pdev->dev.parent->of_node);
 	if (IS_ERR(lpc_ctrl->regmap)) {
 		dev_err(dev, "Couldn't get regmap\n");
 		return -ENODEV;
 	}

 	lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
 	lpc_ctrl->miscdev.name = DEVICE_NAME;
 	lpc_ctrl->miscdev.fops = &aspeed_lpc_ctrl_fops;
 	lpc_ctrl->miscdev.parent = dev;
 	rc = misc_register(&lpc_ctrl->miscdev);
 	if (rc)
 		dev_err(dev, "Unable to register device\n");
 	else
 		dev_info(dev, "Loaded at %pr\n", &resm);

 	return rc;
 }

 static int aspeed_lpc_ctrl_remove(struct platform_device *pdev)
 {
 	struct aspeed_lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);

 	misc_deregister(&lpc_ctrl->miscdev);

 	return 0;
 }

 static const struct of_device_id aspeed_lpc_ctrl_match[] = {
 	{ .compatible = "aspeed,ast2400-lpc-ctrl" },
 	{ .compatible = "aspeed,ast2500-lpc-ctrl" },
 	{ },
 };

 static struct platform_driver aspeed_lpc_ctrl_driver = {
 	.driver = {
 		.name		= DEVICE_NAME,
 		.of_match_table = aspeed_lpc_ctrl_match,
 	},
 	.probe = aspeed_lpc_ctrl_probe,
 	.remove = aspeed_lpc_ctrl_remove,
 };

 module_platform_driver(aspeed_lpc_ctrl_driver);

 MODULE_DEVICE_TABLE(of, aspeed_lpc_ctrl_match);
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Cyril Bur <cyrilbur@gmail.com>");
 MODULE_DESCRIPTION("Control for aspeed 2400/2500 LPC HOST to BMC mappings");
	/*
	* Copyright 2017 IBM Corporation
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/

	#include <linux/mfd/syscon.h>
	#include <linux/miscdevice.h>
	#include <linux/mm.h>
	#include <linux/module.h>
	#include <linux/of_address.h>
	#include <linux/platform_device.h>
	#include <linux/poll.h>
	#include <linux/regmap.h>

	#include <linux/aspeed-lpc-ctrl.h>

	#define DEVICE_NAME "aspeed-lpc-ctrl"

	#define HICR7 0x8
	#define HICR8 0xc

	struct aspeed_lpc_ctrl {
	struct miscdevice miscdev;
	struct regmap *regmap;
	phys_addr_t mem_base;
	resource_size_t mem_size;
	u32 pnor_size;
	u32 pnor_base;
	};

	static struct aspeed_lpc_ctrl file_aspeed_lpc_ctrl(struct file file)
	{
	return container_of(file->private_data, struct aspeed_lpc_ctrl,
	miscdev);
	}

	static int aspeed_lpc_ctrl_mmap(struct file file, struct vm_area_struct vma)
	{
	struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
	unsigned long vsize = vma->vm_end - vma->vm_start;
	pgprot_t prot = vma->vm_page_prot;

	if (vma->vm_pgoff + vsize > lpc_ctrl->mem_base + lpc_ctrl->mem_size)
	return -EINVAL;

	/* ast2400/2500 AHB accesses are not cache coherent */
	prot = pgprot_noncached(prot);

	if (remap_pfn_range(vma, vma->vm_start,
	(lpc_ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff,
	vsize, prot))
	return -EAGAIN;

	return 0;
	}

	static long aspeed_lpc_ctrl_ioctl(struct file *file, unsigned int cmd,
	unsigned long param)
	{
	struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
	void __user p = (void __user )param;
	struct aspeed_lpc_ctrl_mapping map;
	u32 addr;
	u32 size;
	long rc;

	if (copy_from_user(&map, p, sizeof(map)))
	return -EFAULT;

	if (map.flags != 0)
	return -EINVAL;

	switch (cmd) {
	case ASPEED_LPC_CTRL_IOCTL_GET_SIZE:
	/* The flash windows don't report their size */
	if (map.window_type != ASPEED_LPC_CTRL_WINDOW_MEMORY)
	return -EINVAL;

	/* Support more than one window id in the future */
	if (map.window_id != 0)
	return -EINVAL;

	map.size = lpc_ctrl->mem_size;

	return copy_to_user(p, &map, sizeof(map)) ? -EFAULT : 0;
	case ASPEED_LPC_CTRL_IOCTL_MAP:

	/*
	* The top half of HICR7 is the MSB of the BMC address of the
	* mapping.
	* The bottom half of HICR7 is the MSB of the HOST LPC
	* firmware space address of the mapping.
	*
	* The 1 bits in the top of half of HICR8 represent the bits
	* (in the requested address) that should be ignored and
	* replaced with those from the top half of HICR7.
	* The 1 bits in the bottom half of HICR8 represent the bits
	* (in the requested address) that should be kept and pass
	* into the BMC address space.
	*/

	/*
	* It doesn't make sense to talk about a size or offset with
	* low 16 bits set. Both HICR7 and HICR8 talk about the top 16
	* bits of addresses and sizes.
	*/

	if ((map.size & 0x0000ffff) \|\| (map.offset & 0x0000ffff))
	return -EINVAL;

	/*
	* Because of the way the masks work in HICR8 offset has to
	* be a multiple of size.
	*/
	if (map.offset & (map.size - 1))
	return -EINVAL;

	if (map.window_type == ASPEED_LPC_CTRL_WINDOW_FLASH) {
	addr = lpc_ctrl->pnor_base;
	size = lpc_ctrl->pnor_size;
	} else if (map.window_type == ASPEED_LPC_CTRL_WINDOW_MEMORY) {
	addr = lpc_ctrl->mem_base;
	size = lpc_ctrl->mem_size;
	} else {
	return -EINVAL;
	}

	/* Check overflow first! */
	if (map.offset + map.size < map.offset \|\|
	map.offset + map.size > size)
	return -EINVAL;

	if (map.size == 0 \|\| map.size > size)
	return -EINVAL;

	addr += map.offset;

	/*
	* addr (host lpc address) is safe regardless of values. This
	* simply changes the address the host has to request on its
	* side of the LPC bus. This cannot impact the hosts own
	* memory space by surprise as LPC specific accessors are
	* required. The only strange thing that could be done is
	* setting the lower 16 bits but the shift takes care of that.
	*/

	rc = regmap_write(lpc_ctrl->regmap, HICR7,
	(addr \| (map.addr >> 16)));
	if (rc)
	return rc;

	return regmap_write(lpc_ctrl->regmap, HICR8,
	(~(map.size - 1)) \| ((map.size >> 16) - 1));
	}

	return -EINVAL;
	}

	static const struct file_operations aspeed_lpc_ctrl_fops = {
	.owner = THIS_MODULE,
	.mmap = aspeed_lpc_ctrl_mmap,
	.unlocked_ioctl = aspeed_lpc_ctrl_ioctl,
	};

	static int aspeed_lpc_ctrl_probe(struct platform_device *pdev)
	{
	struct aspeed_lpc_ctrl *lpc_ctrl;
	struct device_node *node;
	struct resource resm;
	struct device *dev;
	int rc;

	dev = &pdev->dev;

	lpc_ctrl = devm_kzalloc(dev, sizeof(*lpc_ctrl), GFP_KERNEL);
	if (!lpc_ctrl)
	return -ENOMEM;

	node = of_parse_phandle(dev->of_node, "flash", 0);
	if (!node) {
	dev_err(dev, "Didn't find host pnor flash node\n");
	return -ENODEV;
	}

	rc = of_address_to_resource(node, 1, &resm);
	of_node_put(node);
	if (rc) {
	dev_err(dev, "Couldn't address to resource for flash\n");
	return rc;
	}

	lpc_ctrl->pnor_size = resource_size(&resm);
	lpc_ctrl->pnor_base = resm.start;

	dev_set_drvdata(&pdev->dev, lpc_ctrl);

	node = of_parse_phandle(dev->of_node, "memory-region", 0);
	if (!node) {
	dev_err(dev, "Didn't find reserved memory\n");
	return -EINVAL;
	}

	rc = of_address_to_resource(node, 0, &resm);
	of_node_put(node);
	if (rc) {
	dev_err(dev, "Couldn't address to resource for reserved memory\n");
	return -ENOMEM;
	}

	lpc_ctrl->mem_size = resource_size(&resm);
	lpc_ctrl->mem_base = resm.start;

	lpc_ctrl->regmap = syscon_node_to_regmap(
	pdev->dev.parent->of_node);
	if (IS_ERR(lpc_ctrl->regmap)) {
	dev_err(dev, "Couldn't get regmap\n");
	return -ENODEV;
	}

	lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
	lpc_ctrl->miscdev.name = DEVICE_NAME;
	lpc_ctrl->miscdev.fops = &aspeed_lpc_ctrl_fops;
	lpc_ctrl->miscdev.parent = dev;
	rc = misc_register(&lpc_ctrl->miscdev);
	if (rc)
	dev_err(dev, "Unable to register device\n");
	else
	dev_info(dev, "Loaded at %pr\n", &resm);

	return rc;
	}

	static int aspeed_lpc_ctrl_remove(struct platform_device *pdev)
	{
	struct aspeed_lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);

	misc_deregister(&lpc_ctrl->miscdev);

	return 0;
	}

	static const struct of_device_id aspeed_lpc_ctrl_match[] = {
	{ .compatible = "aspeed,ast2400-lpc-ctrl" },
	{ .compatible = "aspeed,ast2500-lpc-ctrl" },
	{ },
	};

	static struct platform_driver aspeed_lpc_ctrl_driver = {
	.driver = {
	.name = DEVICE_NAME,
	.of_match_table = aspeed_lpc_ctrl_match,
	},
	.probe = aspeed_lpc_ctrl_probe,
	.remove = aspeed_lpc_ctrl_remove,
	};

	module_platform_driver(aspeed_lpc_ctrl_driver);

	MODULE_DEVICE_TABLE(of, aspeed_lpc_ctrl_match);
	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Cyril Bur <cyrilbur@gmail.com>");
	MODULE_DESCRIPTION("Control for aspeed 2400/2500 LPC HOST to BMC mappings");