Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

5 files changed, 1161 insertions, 0 deletions

diff --git a/drivers/soc/aspeed/Kconfig b/drivers/soc/aspeed/Kconfig
new file mode 100644
index 000000000..c95fa30f1
--- /dev/null
+++ b/drivers/soc/aspeed/Kconfig
@@ -0,0 +1,32 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "Aspeed SoC drivers"
+
+config SOC_ASPEED
+	def_bool y
+	depends on ARCH_ASPEED || COMPILE_TEST
+
+config ASPEED_LPC_CTRL
+	depends on SOC_ASPEED && REGMAP && MFD_SYSCON
+	tristate "Aspeed ast2400/2500 HOST LPC to BMC bridge control"
+	help
+	  Control Aspeed ast2400/2500 HOST LPC to BMC mappings through
+	  ioctl()s, the driver also provides a read/write interface to a BMC ram
+	  region where the host LPC read/write region can be buffered.
+
+config ASPEED_LPC_SNOOP
+	tristate "Aspeed ast2500 HOST LPC snoop support"
+	depends on SOC_ASPEED && REGMAP && MFD_SYSCON
+	help
+	  Provides a driver to control the LPC snoop interface which
+	  allows the BMC to listen on and save the data written by
+	  the host to an arbitrary LPC I/O port.
+
+config ASPEED_P2A_CTRL
+	depends on SOC_ASPEED && REGMAP && MFD_SYSCON
+	tristate "Aspeed ast2400/2500 HOST P2A VGA MMIO to BMC bridge control"
+	help
+	  Control Aspeed ast2400/2500 HOST P2A VGA MMIO to BMC mappings through
+	  ioctl()s, the driver also provides an interface for userspace mappings to
+	  a pre-defined region.
+
+endmenu
diff --git a/drivers/soc/aspeed/Makefile b/drivers/soc/aspeed/Makefile
new file mode 100644
index 000000000..b64be47f2
--- /dev/null
+++ b/drivers/soc/aspeed/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_ASPEED_LPC_CTRL)	+= aspeed-lpc-ctrl.o
+obj-$(CONFIG_ASPEED_LPC_SNOOP)	+= aspeed-lpc-snoop.o
+obj-$(CONFIG_ASPEED_P2A_CTRL)	+= aspeed-p2a-ctrl.o
diff --git a/drivers/soc/aspeed/aspeed-lpc-ctrl.c b/drivers/soc/aspeed/aspeed-lpc-ctrl.c
new file mode 100644
index 000000000..71b555c71
--- /dev/null
+++ b/drivers/soc/aspeed/aspeed-lpc-ctrl.c
@@ -0,0 +1,310 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2017 IBM Corporation
+ */
+
+#include <linux/clk.h>
+#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 HICR5 0x0
+#define HICR5_ENL2H	BIT(8)
+#define HICR5_ENFWH	BIT(10)
+
+#define HICR7 0x8
+#define HICR8 0xc
+
+struct aspeed_lpc_ctrl {
+	struct miscdevice	miscdev;
+	struct regmap		*regmap;
+	struct clk		*clk;
+	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 + vma_pages(vma) > lpc_ctrl->mem_size >> PAGE_SHIFT)
+		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);
+	struct device *dev = file->private_data;
+	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;
+
+		/* If memory-region is not described in device tree */
+		if (!lpc_ctrl->mem_size) {
+			dev_dbg(dev, "Didn't find reserved memory\n");
+			return -ENXIO;
+		}
+
+		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) {
+			if (!lpc_ctrl->pnor_size) {
+				dev_dbg(dev, "Didn't find host pnor flash\n");
+				return -ENXIO;
+			}
+			addr = lpc_ctrl->pnor_base;
+			size = lpc_ctrl->pnor_size;
+		} else if (map.window_type == ASPEED_LPC_CTRL_WINDOW_MEMORY) {
+			/* If memory-region is not described in device tree */
+			if (!lpc_ctrl->mem_size) {
+				dev_dbg(dev, "Didn't find reserved memory\n");
+				return -ENXIO;
+			}
+			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;
+
+		rc = regmap_write(lpc_ctrl->regmap, HICR8,
+				(~(map.size - 1)) | ((map.size >> 16) - 1));
+		if (rc)
+			return rc;
+
+		/*
+		 * Enable LPC FHW cycles. This is required for the host to
+		 * access the regions specified.
+		 */
+		return regmap_update_bits(lpc_ctrl->regmap, HICR5,
+				HICR5_ENFWH | HICR5_ENL2H,
+				HICR5_ENFWH | HICR5_ENL2H);
+	}
+
+	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;
+
+	/* If flash is described in device tree then store */
+	node = of_parse_phandle(dev->of_node, "flash", 0);
+	if (!node) {
+		dev_dbg(dev, "Didn't find host pnor flash node\n");
+	} else {
+		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);
+
+	/* If memory-region is described in device tree then store */
+	node = of_parse_phandle(dev->of_node, "memory-region", 0);
+	if (!node) {
+		dev_dbg(dev, "Didn't find reserved memory\n");
+	} else {
+		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 -ENXIO;
+		}
+
+		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->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(lpc_ctrl->clk))
+		return dev_err_probe(dev, PTR_ERR(lpc_ctrl->clk),
+				     "couldn't get clock\n");
+	rc = clk_prepare_enable(lpc_ctrl->clk);
+	if (rc) {
+		dev_err(dev, "couldn't enable clock\n");
+		return rc;
+	}
+
+	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");
+		goto err;
+	}
+
+	return 0;
+
+err:
+	clk_disable_unprepare(lpc_ctrl->clk);
+	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);
+	clk_disable_unprepare(lpc_ctrl->clk);
+
+	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");
diff --git a/drivers/soc/aspeed/aspeed-lpc-snoop.c b/drivers/soc/aspeed/aspeed-lpc-snoop.c
new file mode 100644
index 000000000..538d7aab8
--- /dev/null
+++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c
@@ -0,0 +1,371 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2017 Google Inc
+ *
+ * Provides a simple driver to control the ASPEED LPC snoop interface which
+ * allows the BMC to listen on and save the data written by
+ * the host to an arbitrary LPC I/O port.
+ *
+ * Typically used by the BMC to "watch" host boot progress via port
+ * 0x80 writes made by the BIOS during the boot process.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/fs.h>
+#include <linux/kfifo.h>
+#include <linux/mfd/syscon.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/regmap.h>
+
+#define DEVICE_NAME	"aspeed-lpc-snoop"
+
+#define NUM_SNOOP_CHANNELS 2
+#define SNOOP_FIFO_SIZE 2048
+
+#define HICR5	0x0
+#define HICR5_EN_SNP0W		BIT(0)
+#define HICR5_ENINT_SNP0W	BIT(1)
+#define HICR5_EN_SNP1W		BIT(2)
+#define HICR5_ENINT_SNP1W	BIT(3)
+
+#define HICR6	0x4
+#define HICR6_STR_SNP0W		BIT(0)
+#define HICR6_STR_SNP1W		BIT(1)
+#define SNPWADR	0x10
+#define SNPWADR_CH0_MASK	GENMASK(15, 0)
+#define SNPWADR_CH0_SHIFT	0
+#define SNPWADR_CH1_MASK	GENMASK(31, 16)
+#define SNPWADR_CH1_SHIFT	16
+#define SNPWDR	0x14
+#define SNPWDR_CH0_MASK		GENMASK(7, 0)
+#define SNPWDR_CH0_SHIFT	0
+#define SNPWDR_CH1_MASK		GENMASK(15, 8)
+#define SNPWDR_CH1_SHIFT	8
+#define HICRB	0x80
+#define HICRB_ENSNP0D		BIT(14)
+#define HICRB_ENSNP1D		BIT(15)
+
+struct aspeed_lpc_snoop_model_data {
+	/* The ast2400 has bits 14 and 15 as reserved, whereas the ast2500
+	 * can use them.
+	 */
+	unsigned int has_hicrb_ensnp;
+};
+
+struct aspeed_lpc_snoop_channel {
+	struct kfifo		fifo;
+	wait_queue_head_t	wq;
+	struct miscdevice	miscdev;
+};
+
+struct aspeed_lpc_snoop {
+	struct regmap		*regmap;
+	int			irq;
+	struct clk		*clk;
+	struct aspeed_lpc_snoop_channel chan[NUM_SNOOP_CHANNELS];
+};
+
+static struct aspeed_lpc_snoop_channel *snoop_file_to_chan(struct file *file)
+{
+	return container_of(file->private_data,
+			    struct aspeed_lpc_snoop_channel,
+			    miscdev);
+}
+
+static ssize_t snoop_file_read(struct file *file, char __user *buffer,
+				size_t count, loff_t *ppos)
+{
+	struct aspeed_lpc_snoop_channel *chan = snoop_file_to_chan(file);
+	unsigned int copied;
+	int ret = 0;
+
+	if (kfifo_is_empty(&chan->fifo)) {
+		if (file->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+		ret = wait_event_interruptible(chan->wq,
+				!kfifo_is_empty(&chan->fifo));
+		if (ret == -ERESTARTSYS)
+			return -EINTR;
+	}
+	ret = kfifo_to_user(&chan->fifo, buffer, count, &copied);
+	if (ret)
+		return ret;
+
+	return copied;
+}
+
+static __poll_t snoop_file_poll(struct file *file,
+				    struct poll_table_struct *pt)
+{
+	struct aspeed_lpc_snoop_channel *chan = snoop_file_to_chan(file);
+
+	poll_wait(file, &chan->wq, pt);
+	return !kfifo_is_empty(&chan->fifo) ? EPOLLIN : 0;
+}
+
+static const struct file_operations snoop_fops = {
+	.owner  = THIS_MODULE,
+	.read   = snoop_file_read,
+	.poll   = snoop_file_poll,
+	.llseek = noop_llseek,
+};
+
+/* Save a byte to a FIFO and discard the oldest byte if FIFO is full */
+static void put_fifo_with_discard(struct aspeed_lpc_snoop_channel *chan, u8 val)
+{
+	if (!kfifo_initialized(&chan->fifo))
+		return;
+	if (kfifo_is_full(&chan->fifo))
+		kfifo_skip(&chan->fifo);
+	kfifo_put(&chan->fifo, val);
+	wake_up_interruptible(&chan->wq);
+}
+
+static irqreturn_t aspeed_lpc_snoop_irq(int irq, void *arg)
+{
+	struct aspeed_lpc_snoop *lpc_snoop = arg;
+	u32 reg, data;
+
+	if (regmap_read(lpc_snoop->regmap, HICR6, &reg))
+		return IRQ_NONE;
+
+	/* Check if one of the snoop channels is interrupting */
+	reg &= (HICR6_STR_SNP0W | HICR6_STR_SNP1W);
+	if (!reg)
+		return IRQ_NONE;
+
+	/* Ack pending IRQs */
+	regmap_write(lpc_snoop->regmap, HICR6, reg);
+
+	/* Read and save most recent snoop'ed data byte to FIFO */
+	regmap_read(lpc_snoop->regmap, SNPWDR, &data);
+
+	if (reg & HICR6_STR_SNP0W) {
+		u8 val = (data & SNPWDR_CH0_MASK) >> SNPWDR_CH0_SHIFT;
+
+		put_fifo_with_discard(&lpc_snoop->chan[0], val);
+	}
+	if (reg & HICR6_STR_SNP1W) {
+		u8 val = (data & SNPWDR_CH1_MASK) >> SNPWDR_CH1_SHIFT;
+
+		put_fifo_with_discard(&lpc_snoop->chan[1], val);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int aspeed_lpc_snoop_config_irq(struct aspeed_lpc_snoop *lpc_snoop,
+				       struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int rc;
+
+	lpc_snoop->irq = platform_get_irq(pdev, 0);
+	if (!lpc_snoop->irq)
+		return -ENODEV;
+
+	rc = devm_request_irq(dev, lpc_snoop->irq,
+			      aspeed_lpc_snoop_irq, IRQF_SHARED,
+			      DEVICE_NAME, lpc_snoop);
+	if (rc < 0) {
+		dev_warn(dev, "Unable to request IRQ %d\n", lpc_snoop->irq);
+		lpc_snoop->irq = 0;
+		return rc;
+	}
+
+	return 0;
+}
+
+static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
+				   struct device *dev,
+				   int channel, u16 lpc_port)
+{
+	int rc = 0;
+	u32 hicr5_en, snpwadr_mask, snpwadr_shift, hicrb_en;
+	const struct aspeed_lpc_snoop_model_data *model_data =
+		of_device_get_match_data(dev);
+
+	init_waitqueue_head(&lpc_snoop->chan[channel].wq);
+	/* Create FIFO datastructure */
+	rc = kfifo_alloc(&lpc_snoop->chan[channel].fifo,
+			 SNOOP_FIFO_SIZE, GFP_KERNEL);
+	if (rc)
+		return rc;
+
+	lpc_snoop->chan[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
+	lpc_snoop->chan[channel].miscdev.name =
+		devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel);
+	lpc_snoop->chan[channel].miscdev.fops = &snoop_fops;
+	lpc_snoop->chan[channel].miscdev.parent = dev;
+	rc = misc_register(&lpc_snoop->chan[channel].miscdev);
+	if (rc)
+		return rc;
+
+	/* Enable LPC snoop channel at requested port */
+	switch (channel) {
+	case 0:
+		hicr5_en = HICR5_EN_SNP0W | HICR5_ENINT_SNP0W;
+		snpwadr_mask = SNPWADR_CH0_MASK;
+		snpwadr_shift = SNPWADR_CH0_SHIFT;
+		hicrb_en = HICRB_ENSNP0D;
+		break;
+	case 1:
+		hicr5_en = HICR5_EN_SNP1W | HICR5_ENINT_SNP1W;
+		snpwadr_mask = SNPWADR_CH1_MASK;
+		snpwadr_shift = SNPWADR_CH1_SHIFT;
+		hicrb_en = HICRB_ENSNP1D;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	regmap_update_bits(lpc_snoop->regmap, HICR5, hicr5_en, hicr5_en);
+	regmap_update_bits(lpc_snoop->regmap, SNPWADR, snpwadr_mask,
+			   lpc_port << snpwadr_shift);
+	if (model_data->has_hicrb_ensnp)
+		regmap_update_bits(lpc_snoop->regmap, HICRB,
+				hicrb_en, hicrb_en);
+
+	return rc;
+}
+
+static void aspeed_lpc_disable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
+				     int channel)
+{
+	switch (channel) {
+	case 0:
+		regmap_update_bits(lpc_snoop->regmap, HICR5,
+				   HICR5_EN_SNP0W | HICR5_ENINT_SNP0W,
+				   0);
+		break;
+	case 1:
+		regmap_update_bits(lpc_snoop->regmap, HICR5,
+				   HICR5_EN_SNP1W | HICR5_ENINT_SNP1W,
+				   0);
+		break;
+	default:
+		return;
+	}
+
+	kfifo_free(&lpc_snoop->chan[channel].fifo);
+	misc_deregister(&lpc_snoop->chan[channel].miscdev);
+}
+
+static int aspeed_lpc_snoop_probe(struct platform_device *pdev)
+{
+	struct aspeed_lpc_snoop *lpc_snoop;
+	struct device *dev;
+	u32 port;
+	int rc;
+
+	dev = &pdev->dev;
+
+	lpc_snoop = devm_kzalloc(dev, sizeof(*lpc_snoop), GFP_KERNEL);
+	if (!lpc_snoop)
+		return -ENOMEM;
+
+	lpc_snoop->regmap = syscon_node_to_regmap(
+			pdev->dev.parent->of_node);
+	if (IS_ERR(lpc_snoop->regmap)) {
+		dev_err(dev, "Couldn't get regmap\n");
+		return -ENODEV;
+	}
+
+	dev_set_drvdata(&pdev->dev, lpc_snoop);
+
+	rc = of_property_read_u32_index(dev->of_node, "snoop-ports", 0, &port);
+	if (rc) {
+		dev_err(dev, "no snoop ports configured\n");
+		return -ENODEV;
+	}
+
+	lpc_snoop->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(lpc_snoop->clk)) {
+		rc = PTR_ERR(lpc_snoop->clk);
+		if (rc != -EPROBE_DEFER)
+			dev_err(dev, "couldn't get clock\n");
+		return rc;
+	}
+	rc = clk_prepare_enable(lpc_snoop->clk);
+	if (rc) {
+		dev_err(dev, "couldn't enable clock\n");
+		return rc;
+	}
+
+	rc = aspeed_lpc_snoop_config_irq(lpc_snoop, pdev);
+	if (rc)
+		goto err;
+
+	rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 0, port);
+	if (rc)
+		goto err;
+
+	/* Configuration of 2nd snoop channel port is optional */
+	if (of_property_read_u32_index(dev->of_node, "snoop-ports",
+				       1, &port) == 0) {
+		rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 1, port);
+		if (rc) {
+			aspeed_lpc_disable_snoop(lpc_snoop, 0);
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	clk_disable_unprepare(lpc_snoop->clk);
+
+	return rc;
+}
+
+static int aspeed_lpc_snoop_remove(struct platform_device *pdev)
+{
+	struct aspeed_lpc_snoop *lpc_snoop = dev_get_drvdata(&pdev->dev);
+
+	/* Disable both snoop channels */
+	aspeed_lpc_disable_snoop(lpc_snoop, 0);
+	aspeed_lpc_disable_snoop(lpc_snoop, 1);
+
+	clk_disable_unprepare(lpc_snoop->clk);
+
+	return 0;
+}
+
+static const struct aspeed_lpc_snoop_model_data ast2400_model_data = {
+	.has_hicrb_ensnp = 0,
+};
+
+static const struct aspeed_lpc_snoop_model_data ast2500_model_data = {
+	.has_hicrb_ensnp = 1,
+};
+
+static const struct of_device_id aspeed_lpc_snoop_match[] = {
+	{ .compatible = "aspeed,ast2400-lpc-snoop",
+	  .data = &ast2400_model_data },
+	{ .compatible = "aspeed,ast2500-lpc-snoop",
+	  .data = &ast2500_model_data },
+	{ },
+};
+
+static struct platform_driver aspeed_lpc_snoop_driver = {
+	.driver = {
+		.name		= DEVICE_NAME,
+		.of_match_table = aspeed_lpc_snoop_match,
+	},
+	.probe = aspeed_lpc_snoop_probe,
+	.remove = aspeed_lpc_snoop_remove,
+};
+
+module_platform_driver(aspeed_lpc_snoop_driver);
+
+MODULE_DEVICE_TABLE(of, aspeed_lpc_snoop_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Robert Lippert <rlippert@google.com>");
+MODULE_DESCRIPTION("Linux driver to control Aspeed LPC snoop functionality");
diff --git a/drivers/soc/aspeed/aspeed-p2a-ctrl.c b/drivers/soc/aspeed/aspeed-p2a-ctrl.c
new file mode 100644
index 000000000..20b5fb2a2
--- /dev/null
+++ b/drivers/soc/aspeed/aspeed-p2a-ctrl.c
@@ -0,0 +1,444 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2019 Google Inc
+ *
+ * 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.
+ *
+ * Provides a simple driver to control the ASPEED P2A interface which allows
+ * the host to read and write to various regions of the BMC's memory.
+ */
+
+#include <linux/fs.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/miscdevice.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include <linux/aspeed-p2a-ctrl.h>
+
+#define DEVICE_NAME	"aspeed-p2a-ctrl"
+
+/* SCU2C is a Misc. Control Register. */
+#define SCU2C 0x2c
+/* SCU180 is the PCIe Configuration Setting Control Register. */
+#define SCU180 0x180
+/* Bit 1 controls the P2A bridge, while bit 0 controls the entire VGA device
+ * on the PCI bus.
+ */
+#define SCU180_ENP2A BIT(1)
+
+/* The ast2400/2500 both have six ranges. */
+#define P2A_REGION_COUNT 6
+
+struct region {
+	u64 min;
+	u64 max;
+	u32 bit;
+};
+
+struct aspeed_p2a_model_data {
+	/* min, max, bit */
+	struct region regions[P2A_REGION_COUNT];
+};
+
+struct aspeed_p2a_ctrl {
+	struct miscdevice miscdev;
+	struct regmap *regmap;
+
+	const struct aspeed_p2a_model_data *config;
+
+	/* Access to these needs to be locked, held via probe, mapping ioctl,
+	 * and release, remove.
+	 */
+	struct mutex tracking;
+	u32 readers;
+	u32 readerwriters[P2A_REGION_COUNT];
+
+	phys_addr_t mem_base;
+	resource_size_t mem_size;
+};
+
+struct aspeed_p2a_user {
+	struct file *file;
+	struct aspeed_p2a_ctrl *parent;
+
+	/* The entire memory space is opened for reading once the bridge is
+	 * enabled, therefore this needs only to be tracked once per user.
+	 * If any user has it open for read, the bridge must stay enabled.
+	 */
+	u32 read;
+
+	/* Each entry of the array corresponds to a P2A Region.  If the user
+	 * opens for read or readwrite, the reference goes up here.  On
+	 * release, this array is walked and references adjusted accordingly.
+	 */
+	u32 readwrite[P2A_REGION_COUNT];
+};
+
+static void aspeed_p2a_enable_bridge(struct aspeed_p2a_ctrl *p2a_ctrl)
+{
+	regmap_update_bits(p2a_ctrl->regmap,
+		SCU180, SCU180_ENP2A, SCU180_ENP2A);
+}
+
+static void aspeed_p2a_disable_bridge(struct aspeed_p2a_ctrl *p2a_ctrl)
+{
+	regmap_update_bits(p2a_ctrl->regmap, SCU180, SCU180_ENP2A, 0);
+}
+
+static int aspeed_p2a_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	unsigned long vsize;
+	pgprot_t prot;
+	struct aspeed_p2a_user *priv = file->private_data;
+	struct aspeed_p2a_ctrl *ctrl = priv->parent;
+
+	if (ctrl->mem_base == 0 && ctrl->mem_size == 0)
+		return -EINVAL;
+
+	vsize = vma->vm_end - vma->vm_start;
+	prot = vma->vm_page_prot;
+
+	if (vma->vm_pgoff + vma_pages(vma) > ctrl->mem_size >> PAGE_SHIFT)
+		return -EINVAL;
+
+	/* ast2400/2500 AHB accesses are not cache coherent */
+	prot = pgprot_noncached(prot);
+
+	if (remap_pfn_range(vma, vma->vm_start,
+		(ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff,
+		vsize, prot))
+		return -EAGAIN;
+
+	return 0;
+}
+
+static bool aspeed_p2a_region_acquire(struct aspeed_p2a_user *priv,
+		struct aspeed_p2a_ctrl *ctrl,
+		struct aspeed_p2a_ctrl_mapping *map)
+{
+	int i;
+	u64 base, end;
+	bool matched = false;
+
+	base = map->addr;
+	end = map->addr + (map->length - 1);
+
+	/* If the value is a legal u32, it will find a match. */
+	for (i = 0; i < P2A_REGION_COUNT; i++) {
+		const struct region *curr = &ctrl->config->regions[i];
+
+		/* If the top of this region is lower than your base, skip it.
+		 */
+		if (curr->max < base)
+			continue;
+
+		/* If the bottom of this region is higher than your end, bail.
+		 */
+		if (curr->min > end)
+			break;
+
+		/* Lock this and update it, therefore it someone else is
+		 * closing their file out, this'll preserve the increment.
+		 */
+		mutex_lock(&ctrl->tracking);
+		ctrl->readerwriters[i] += 1;
+		mutex_unlock(&ctrl->tracking);
+
+		/* Track with the user, so when they close their file, we can
+		 * decrement properly.
+		 */
+		priv->readwrite[i] += 1;
+
+		/* Enable the region as read-write. */
+		regmap_update_bits(ctrl->regmap, SCU2C, curr->bit, 0);
+		matched = true;
+	}
+
+	return matched;
+}
+
+static long aspeed_p2a_ioctl(struct file *file, unsigned int cmd,
+		unsigned long data)
+{
+	struct aspeed_p2a_user *priv = file->private_data;
+	struct aspeed_p2a_ctrl *ctrl = priv->parent;
+	void __user *arg = (void __user *)data;
+	struct aspeed_p2a_ctrl_mapping map;
+
+	if (copy_from_user(&map, arg, sizeof(map)))
+		return -EFAULT;
+
+	switch (cmd) {
+	case ASPEED_P2A_CTRL_IOCTL_SET_WINDOW:
+		/* If they want a region to be read-only, since the entire
+		 * region is read-only once enabled, we just need to track this
+		 * user wants to read from the bridge, and if it's not enabled.
+		 * Enable it.
+		 */
+		if (map.flags == ASPEED_P2A_CTRL_READ_ONLY) {
+			mutex_lock(&ctrl->tracking);
+			ctrl->readers += 1;
+			mutex_unlock(&ctrl->tracking);
+
+			/* Track with the user, so when they close their file,
+			 * we can decrement properly.
+			 */
+			priv->read += 1;
+		} else if (map.flags == ASPEED_P2A_CTRL_READWRITE) {
+			/* If we don't acquire any region return error. */
+			if (!aspeed_p2a_region_acquire(priv, ctrl, &map)) {
+				return -EINVAL;
+			}
+		} else {
+			/* Invalid map flags. */
+			return -EINVAL;
+		}
+
+		aspeed_p2a_enable_bridge(ctrl);
+		return 0;
+	case ASPEED_P2A_CTRL_IOCTL_GET_MEMORY_CONFIG:
+		/* This is a request for the memory-region and corresponding
+		 * length that is used by the driver for mmap.
+		 */
+
+		map.flags = 0;
+		map.addr = ctrl->mem_base;
+		map.length = ctrl->mem_size;
+
+		return copy_to_user(arg, &map, sizeof(map)) ? -EFAULT : 0;
+	}
+
+	return -EINVAL;
+}
+
+
+/*
+ * When a user opens this file, we create a structure to track their mappings.
+ *
+ * A user can map a region as read-only (bridge enabled), or read-write (bit
+ * flipped, and bridge enabled).  Either way, this tracking is used, s.t. when
+ * they release the device references are handled.
+ *
+ * The bridge is not enabled until a user calls an ioctl to map a region,
+ * simply opening the device does not enable it.
+ */
+static int aspeed_p2a_open(struct inode *inode, struct file *file)
+{
+	struct aspeed_p2a_user *priv;
+
+	priv = kmalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->file = file;
+	priv->read = 0;
+	memset(priv->readwrite, 0, sizeof(priv->readwrite));
+
+	/* The file's private_data is initialized to the p2a_ctrl. */
+	priv->parent = file->private_data;
+
+	/* Set the file's private_data to the user's data. */
+	file->private_data = priv;
+
+	return 0;
+}
+
+/*
+ * This will close the users mappings.  It will go through what they had opened
+ * for readwrite, and decrement those counts.  If at the end, this is the last
+ * user, it'll close the bridge.
+ */
+static int aspeed_p2a_release(struct inode *inode, struct file *file)
+{
+	int i;
+	u32 bits = 0;
+	bool open_regions = false;
+	struct aspeed_p2a_user *priv = file->private_data;
+
+	/* Lock others from changing these values until everything is updated
+	 * in one pass.
+	 */
+	mutex_lock(&priv->parent->tracking);
+
+	priv->parent->readers -= priv->read;
+
+	for (i = 0; i < P2A_REGION_COUNT; i++) {
+		priv->parent->readerwriters[i] -= priv->readwrite[i];
+
+		if (priv->parent->readerwriters[i] > 0)
+			open_regions = true;
+		else
+			bits |= priv->parent->config->regions[i].bit;
+	}
+
+	/* Setting a bit to 1 disables the region, so let's just OR with the
+	 * above to disable any.
+	 */
+
+	/* Note, if another user is trying to ioctl, they can't grab tracking,
+	 * and therefore can't grab either register mutex.
+	 * If another user is trying to close, they can't grab tracking either.
+	 */
+	regmap_update_bits(priv->parent->regmap, SCU2C, bits, bits);
+
+	/* If parent->readers is zero and open windows is 0, disable the
+	 * bridge.
+	 */
+	if (!open_regions && priv->parent->readers == 0)
+		aspeed_p2a_disable_bridge(priv->parent);
+
+	mutex_unlock(&priv->parent->tracking);
+
+	kfree(priv);
+
+	return 0;
+}
+
+static const struct file_operations aspeed_p2a_ctrl_fops = {
+	.owner = THIS_MODULE,
+	.mmap = aspeed_p2a_mmap,
+	.unlocked_ioctl = aspeed_p2a_ioctl,
+	.open = aspeed_p2a_open,
+	.release = aspeed_p2a_release,
+};
+
+/* The regions are controlled by SCU2C */
+static void aspeed_p2a_disable_all(struct aspeed_p2a_ctrl *p2a_ctrl)
+{
+	int i;
+	u32 value = 0;
+
+	for (i = 0; i < P2A_REGION_COUNT; i++)
+		value |= p2a_ctrl->config->regions[i].bit;
+
+	regmap_update_bits(p2a_ctrl->regmap, SCU2C, value, value);
+
+	/* Disable the bridge. */
+	aspeed_p2a_disable_bridge(p2a_ctrl);
+}
+
+static int aspeed_p2a_ctrl_probe(struct platform_device *pdev)
+{
+	struct aspeed_p2a_ctrl *misc_ctrl;
+	struct device *dev;
+	struct resource resm;
+	struct device_node *node;
+	int rc = 0;
+
+	dev = &pdev->dev;
+
+	misc_ctrl = devm_kzalloc(dev, sizeof(*misc_ctrl), GFP_KERNEL);
+	if (!misc_ctrl)
+		return -ENOMEM;
+
+	mutex_init(&misc_ctrl->tracking);
+
+	/* optional. */
+	node = of_parse_phandle(dev->of_node, "memory-region", 0);
+	if (node) {
+		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 -ENODEV;
+		}
+
+		misc_ctrl->mem_size = resource_size(&resm);
+		misc_ctrl->mem_base = resm.start;
+	}
+
+	misc_ctrl->regmap = syscon_node_to_regmap(pdev->dev.parent->of_node);
+	if (IS_ERR(misc_ctrl->regmap)) {
+		dev_err(dev, "Couldn't get regmap\n");
+		return -ENODEV;
+	}
+
+	misc_ctrl->config = of_device_get_match_data(dev);
+
+	dev_set_drvdata(&pdev->dev, misc_ctrl);
+
+	aspeed_p2a_disable_all(misc_ctrl);
+
+	misc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
+	misc_ctrl->miscdev.name = DEVICE_NAME;
+	misc_ctrl->miscdev.fops = &aspeed_p2a_ctrl_fops;
+	misc_ctrl->miscdev.parent = dev;
+
+	rc = misc_register(&misc_ctrl->miscdev);
+	if (rc)
+		dev_err(dev, "Unable to register device\n");
+
+	return rc;
+}
+
+static int aspeed_p2a_ctrl_remove(struct platform_device *pdev)
+{
+	struct aspeed_p2a_ctrl *p2a_ctrl = dev_get_drvdata(&pdev->dev);
+
+	misc_deregister(&p2a_ctrl->miscdev);
+
+	return 0;
+}
+
+#define SCU2C_DRAM	BIT(25)
+#define SCU2C_SPI	BIT(24)
+#define SCU2C_SOC	BIT(23)
+#define SCU2C_FLASH	BIT(22)
+
+static const struct aspeed_p2a_model_data ast2400_model_data = {
+	.regions = {
+		{0x00000000, 0x17FFFFFF, SCU2C_FLASH},
+		{0x18000000, 0x1FFFFFFF, SCU2C_SOC},
+		{0x20000000, 0x2FFFFFFF, SCU2C_FLASH},
+		{0x30000000, 0x3FFFFFFF, SCU2C_SPI},
+		{0x40000000, 0x5FFFFFFF, SCU2C_DRAM},
+		{0x60000000, 0xFFFFFFFF, SCU2C_SOC},
+	}
+};
+
+static const struct aspeed_p2a_model_data ast2500_model_data = {
+	.regions = {
+		{0x00000000, 0x0FFFFFFF, SCU2C_FLASH},
+		{0x10000000, 0x1FFFFFFF, SCU2C_SOC},
+		{0x20000000, 0x3FFFFFFF, SCU2C_FLASH},
+		{0x40000000, 0x5FFFFFFF, SCU2C_SOC},
+		{0x60000000, 0x7FFFFFFF, SCU2C_SPI},
+		{0x80000000, 0xFFFFFFFF, SCU2C_DRAM},
+	}
+};
+
+static const struct of_device_id aspeed_p2a_ctrl_match[] = {
+	{ .compatible = "aspeed,ast2400-p2a-ctrl",
+	  .data = &ast2400_model_data },
+	{ .compatible = "aspeed,ast2500-p2a-ctrl",
+	  .data = &ast2500_model_data },
+	{ },
+};
+
+static struct platform_driver aspeed_p2a_ctrl_driver = {
+	.driver = {
+		.name		= DEVICE_NAME,
+		.of_match_table = aspeed_p2a_ctrl_match,
+	},
+	.probe = aspeed_p2a_ctrl_probe,
+	.remove = aspeed_p2a_ctrl_remove,
+};
+
+module_platform_driver(aspeed_p2a_ctrl_driver);
+
+MODULE_DEVICE_TABLE(of, aspeed_p2a_ctrl_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick Venture <venture@google.com>");
+MODULE_DESCRIPTION("Control for aspeed 2400/2500 P2A VGA HOST to BMC mappings");