1 files changed, 285 insertions, 0 deletions
diff --git a/drivers/platform/chrome/wilco_ec/debugfs.c b/drivers/platform/chrome/wilco_ec/debugfs.c
new file mode 100644
index 000000000..a812788a0
--- /dev/null
+++ b/drivers/platform/chrome/wilco_ec/debugfs.c
@@ -0,0 +1,285 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * debugfs attributes for Wilco EC
+ *
+ * Copyright 2019 Google LLC
+ *
+ * See Documentation/ABI/testing/debugfs-wilco-ec for usage.
+ */
+
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/platform_data/wilco-ec.h>
+#include <linux/platform_device.h>
+
+#define DRV_NAME "wilco-ec-debugfs"
+
+/* The raw bytes will take up more space when represented as a hex string */
+#define FORMATTED_BUFFER_SIZE (EC_MAILBOX_DATA_SIZE * 4)
+
+struct wilco_ec_debugfs {
+	struct wilco_ec_device *ec;
+	struct dentry *dir;
+	size_t response_size;
+	u8 raw_data[EC_MAILBOX_DATA_SIZE];
+	u8 formatted_data[FORMATTED_BUFFER_SIZE];
+};
+static struct wilco_ec_debugfs *debug_info;
+
+/**
+ * parse_hex_sentence() - Convert a ascii hex representation into byte array.
+ * @in: Input buffer of ascii.
+ * @isize: Length of input buffer.
+ * @out: Output buffer.
+ * @osize: Length of output buffer, e.g. max number of bytes to parse.
+ *
+ * An valid input is a series of ascii hexadecimal numbers, separated by spaces.
+ * An example valid input is
+ * "   00 f2 0    000076 6 0  ff"
+ *
+ * If an individual "word" within the hex sentence is longer than MAX_WORD_SIZE,
+ * then the sentence is illegal, and parsing will fail.
+ *
+ * Return: Number of bytes parsed, or negative error code on failure.
+ */
+static int parse_hex_sentence(const char *in, int isize, u8 *out, int osize)
+{
+	int n_parsed = 0;
+	int word_start = 0;
+	int word_end;
+	int word_len;
+	/* Temp buffer for holding a "word" of chars that represents one byte */
+	#define MAX_WORD_SIZE 16
+	char tmp[MAX_WORD_SIZE + 1];
+	u8 byte;
+
+	while (word_start < isize && n_parsed < osize) {
+		/* Find the start of the next word */
+		while (word_start < isize && isspace(in[word_start]))
+			word_start++;
+		 /* reached the end of the input before next word? */
+		if (word_start >= isize)
+			break;
+
+		/* Find the end of this word */
+		word_end = word_start;
+		while (word_end < isize && !isspace(in[word_end]))
+			word_end++;
+
+		/* Copy to a tmp NULL terminated string */
+		word_len = word_end - word_start;
+		if (word_len > MAX_WORD_SIZE)
+			return -EINVAL;
+		memcpy(tmp, in + word_start, word_len);
+		tmp[word_len] = '\0';
+
+		/*
+		 * Convert from hex string, place in output. If fails to parse,
+		 * just return -EINVAL because specific error code is only
+		 * relevant for this one word, returning it would be confusing.
+		 */
+		if (kstrtou8(tmp, 16, &byte))
+			return -EINVAL;
+		out[n_parsed++] = byte;
+
+		word_start = word_end;
+	}
+	return n_parsed;
+}
+
+/* The message type takes up two bytes*/
+#define TYPE_AND_DATA_SIZE ((EC_MAILBOX_DATA_SIZE) + 2)
+
+static ssize_t raw_write(struct file *file, const char __user *user_buf,
+			 size_t count, loff_t *ppos)
+{
+	char *buf = debug_info->formatted_data;
+	struct wilco_ec_message msg;
+	u8 request_data[TYPE_AND_DATA_SIZE];
+	ssize_t kcount;
+	int ret;
+
+	if (count > FORMATTED_BUFFER_SIZE)
+		return -EINVAL;
+
+	kcount = simple_write_to_buffer(buf, FORMATTED_BUFFER_SIZE, ppos,
+					user_buf, count);
+	if (kcount < 0)
+		return kcount;
+
+	ret = parse_hex_sentence(buf, kcount, request_data, TYPE_AND_DATA_SIZE);
+	if (ret < 0)
+		return ret;
+	/* Need at least two bytes for message type and one byte of data */
+	if (ret < 3)
+		return -EINVAL;
+
+	msg.type = request_data[0] << 8 | request_data[1];
+	msg.flags = 0;
+	msg.request_data = request_data + 2;
+	msg.request_size = ret - 2;
+	memset(debug_info->raw_data, 0, sizeof(debug_info->raw_data));
+	msg.response_data = debug_info->raw_data;
+	msg.response_size = EC_MAILBOX_DATA_SIZE;
+
+	ret = wilco_ec_mailbox(debug_info->ec, &msg);
+	if (ret < 0)
+		return ret;
+	debug_info->response_size = ret;
+
+	return count;
+}
+
+static ssize_t raw_read(struct file *file, char __user *user_buf, size_t count,
+			loff_t *ppos)
+{
+	int fmt_len = 0;
+
+	if (debug_info->response_size) {
+		fmt_len = hex_dump_to_buffer(debug_info->raw_data,
+					     debug_info->response_size,
+					     16, 1, debug_info->formatted_data,
+					     sizeof(debug_info->formatted_data),
+					     true);
+		/* Only return response the first time it is read */
+		debug_info->response_size = 0;
+	}
+
+	return simple_read_from_buffer(user_buf, count, ppos,
+				       debug_info->formatted_data, fmt_len);
+}
+
+static const struct file_operations fops_raw = {
+	.owner = THIS_MODULE,
+	.read = raw_read,
+	.write = raw_write,
+	.llseek = no_llseek,
+};
+
+#define CMD_KB_CHROME		0x88
+#define SUB_CMD_H1_GPIO		0x0A
+#define SUB_CMD_TEST_EVENT	0x0B
+
+struct ec_request {
+	u8 cmd;		/* Always CMD_KB_CHROME */
+	u8 reserved;
+	u8 sub_cmd;
+} __packed;
+
+struct ec_response {
+	u8 status;	/* 0 if allowed */
+	u8 val;
+} __packed;
+
+static int send_ec_cmd(struct wilco_ec_device *ec, u8 sub_cmd, u8 *out_val)
+{
+	struct ec_request rq;
+	struct ec_response rs;
+	struct wilco_ec_message msg;
+	int ret;
+
+	memset(&rq, 0, sizeof(rq));
+	rq.cmd = CMD_KB_CHROME;
+	rq.sub_cmd = sub_cmd;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.type = WILCO_EC_MSG_LEGACY;
+	msg.request_data = &rq;
+	msg.request_size = sizeof(rq);
+	msg.response_data = &rs;
+	msg.response_size = sizeof(rs);
+	ret = wilco_ec_mailbox(ec, &msg);
+	if (ret < 0)
+		return ret;
+	if (rs.status)
+		return -EIO;
+
+	*out_val = rs.val;
+
+	return 0;
+}
+
+/**
+ * h1_gpio_get() - Gets h1 gpio status.
+ * @arg: The wilco EC device.
+ * @val: BIT(0)=ENTRY_TO_FACT_MODE, BIT(1)=SPI_CHROME_SEL
+ */
+static int h1_gpio_get(void *arg, u64 *val)
+{
+	int ret;
+
+	ret = send_ec_cmd(arg, SUB_CMD_H1_GPIO, (u8 *)val);
+	if (ret == 0)
+		*val &= 0xFF;
+	return ret;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(fops_h1_gpio, h1_gpio_get, NULL, "0x%02llx\n");
+
+/**
+ * test_event_set() - Sends command to EC to cause an EC test event.
+ * @arg: The wilco EC device.
+ * @val: unused.
+ */
+static int test_event_set(void *arg, u64 val)
+{
+	u8 ret;
+
+	return send_ec_cmd(arg, SUB_CMD_TEST_EVENT, &ret);
+}
+
+/* Format is unused since it is only required for get method which is NULL */
+DEFINE_DEBUGFS_ATTRIBUTE(fops_test_event, NULL, test_event_set, "%llu\n");
+
+/**
+ * wilco_ec_debugfs_probe() - Create the debugfs node
+ * @pdev: The platform device, probably created in core.c
+ *
+ * Try to create a debugfs node. If it fails, then we don't want to change
+ * behavior at all, this is for debugging after all. Just fail silently.
+ *
+ * Return: 0 always.
+ */
+static int wilco_ec_debugfs_probe(struct platform_device *pdev)
+{
+	struct wilco_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
+
+	debug_info = devm_kzalloc(&pdev->dev, sizeof(*debug_info), GFP_KERNEL);
+	if (!debug_info)
+		return 0;
+	debug_info->ec = ec;
+	debug_info->dir = debugfs_create_dir("wilco_ec", NULL);
+	if (!debug_info->dir)
+		return 0;
+	debugfs_create_file("raw", 0644, debug_info->dir, NULL, &fops_raw);
+	debugfs_create_file("h1_gpio", 0444, debug_info->dir, ec,
+			    &fops_h1_gpio);
+	debugfs_create_file("test_event", 0200, debug_info->dir, ec,
+			    &fops_test_event);
+
+	return 0;
+}
+
+static int wilco_ec_debugfs_remove(struct platform_device *pdev)
+{
+	debugfs_remove_recursive(debug_info->dir);
+
+	return 0;
+}
+
+static struct platform_driver wilco_ec_debugfs_driver = {
+	.driver = {
+		.name = DRV_NAME,
+	},
+	.probe = wilco_ec_debugfs_probe,
+	.remove = wilco_ec_debugfs_remove,
+};
+
+module_platform_driver(wilco_ec_debugfs_driver);
+
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Wilco EC debugfs driver");