1 files changed, 266 insertions, 0 deletions
diff --git a/drivers/misc/aspeed-lpc-ctrl.c b/drivers/misc/aspeed-lpc-ctrl.c
new file mode 100644
index 000000000000..b5439643f54b
--- /dev/null
+++ b/drivers/misc/aspeed-lpc-ctrl.c
@@ -0,0 +1,266 @@
+/*
+ * 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");