1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Xilinx Zynq MPSoC Firmware layer for debugfs APIs
  4 *
  5 *  Copyright (C) 2014-2018 Xilinx, Inc.
  6 *
  7 *  Michal Simek <michal.simek@xilinx.com>
  8 *  Davorin Mista <davorin.mista@aggios.com>
  9 *  Jolly Shah <jollys@xilinx.com>
 10 *  Rajan Vaja <rajanv@xilinx.com>
 11 */
 12
 13#include <linux/compiler.h>
 14#include <linux/module.h>
 15#include <linux/slab.h>
 16#include <linux/debugfs.h>
 17#include <linux/uaccess.h>
 18
 19#include <linux/firmware/xlnx-zynqmp.h>
 20#include "zynqmp-debug.h"
 21
 22#define PM_API_NAME_LEN			50
 23
 24struct pm_api_info {
 25	u32 api_id;
 26	char api_name[PM_API_NAME_LEN];
 27	char api_name_len;
 28};
 29
 30static char debugfs_buf[PAGE_SIZE];
 31
 32#define PM_API(id)		 {id, #id, strlen(#id)}
 33static struct pm_api_info pm_api_list[] = {
 34	PM_API(PM_GET_API_VERSION),
 35	PM_API(PM_QUERY_DATA),
 36};
 37
 38static struct dentry *firmware_debugfs_root;
 39
 40/**
 41 * zynqmp_pm_argument_value() - Extract argument value from a PM-API request
 42 * @arg:	Entered PM-API argument in string format
 43 *
 44 * Return: Argument value in unsigned integer format on success
 45 *	   0 otherwise
 46 */
 47static u64 zynqmp_pm_argument_value(char *arg)
 48{
 49	u64 value;
 50
 51	if (!arg)
 52		return 0;
 53
 54	if (!kstrtou64(arg, 0, &value))
 55		return value;
 56
 57	return 0;
 58}
 59
 60/**
 61 * get_pm_api_id() - Extract API-ID from a PM-API request
 62 * @pm_api_req:		Entered PM-API argument in string format
 63 * @pm_id:		API-ID
 64 *
 65 * Return: 0 on success else error code
 66 */
 67static int get_pm_api_id(char *pm_api_req, u32 *pm_id)
 68{
 69	int i;
 70
 71	for (i = 0; i < ARRAY_SIZE(pm_api_list) ; i++) {
 72		if (!strncasecmp(pm_api_req, pm_api_list[i].api_name,
 73				 pm_api_list[i].api_name_len)) {
 74			*pm_id = pm_api_list[i].api_id;
 75			break;
 76		}
 77	}
 78
 79	/* If no name was entered look for PM-API ID instead */
 80	if (i == ARRAY_SIZE(pm_api_list) && kstrtouint(pm_api_req, 10, pm_id))
 81		return -EINVAL;
 82
 83	return 0;
 84}
 85
 86static int process_api_request(u32 pm_id, u64 *pm_api_arg, u32 *pm_api_ret)
 87{
 88	u32 pm_api_version;
 89	int ret;
 90	struct zynqmp_pm_query_data qdata = {0};
 91
 92	switch (pm_id) {
 93	case PM_GET_API_VERSION:
 94		ret = zynqmp_pm_get_api_version(&pm_api_version);
 95		sprintf(debugfs_buf, "PM-API Version = %d.%d\n",
 96			pm_api_version >> 16, pm_api_version & 0xffff);
 97		break;
 98	case PM_QUERY_DATA:
 99		qdata.qid = pm_api_arg[0];
100		qdata.arg1 = pm_api_arg[1];
101		qdata.arg2 = pm_api_arg[2];
102		qdata.arg3 = pm_api_arg[3];
103
104		ret = zynqmp_pm_query_data(qdata, pm_api_ret);
105		if (ret)
106			break;
107
108		switch (qdata.qid) {
109		case PM_QID_CLOCK_GET_NAME:
110			sprintf(debugfs_buf, "Clock name = %s\n",
111				(char *)pm_api_ret);
112			break;
113		case PM_QID_CLOCK_GET_FIXEDFACTOR_PARAMS:
114			sprintf(debugfs_buf, "Multiplier = %d, Divider = %d\n",
115				pm_api_ret[1], pm_api_ret[2]);
116			break;
117		default:
118			sprintf(debugfs_buf,
119				"data[0] = 0x%08x\ndata[1] = 0x%08x\n data[2] = 0x%08x\ndata[3] = 0x%08x\n",
120				pm_api_ret[0], pm_api_ret[1],
121				pm_api_ret[2], pm_api_ret[3]);
122		}
123		break;
124	default:
125		sprintf(debugfs_buf, "Unsupported PM-API request\n");
126		ret = -EINVAL;
127	}
128
129	return ret;
130}
131
132/**
133 * zynqmp_pm_debugfs_api_write() - debugfs write function
134 * @file:	User file
135 * @ptr:	User entered PM-API string
136 * @len:	Length of the userspace buffer
137 * @off:	Offset within the file
138 *
139 * Used for triggering pm api functions by writing
140 * echo <pm_api_id>	> /sys/kernel/debug/zynqmp_pm/power or
141 * echo <pm_api_name>	> /sys/kernel/debug/zynqmp_pm/power
142 *
143 * Return: Number of bytes copied if PM-API request succeeds,
144 *	   the corresponding error code otherwise
145 */
146static ssize_t zynqmp_pm_debugfs_api_write(struct file *file,
147					   const char __user *ptr, size_t len,
148					   loff_t *off)
149{
150	char *kern_buff, *tmp_buff;
151	char *pm_api_req;
152	u32 pm_id = 0;
153	u64 pm_api_arg[4] = {0, 0, 0, 0};
154	/* Return values from PM APIs calls */
155	u32 pm_api_ret[4] = {0, 0, 0, 0};
156
157	int ret;
158	int i = 0;
159
160	strcpy(debugfs_buf, "");
161
162	if (*off != 0 || len <= 1 || len > PAGE_SIZE - 1)
163		return -EINVAL;
164
165	kern_buff = memdup_user_nul(ptr, len);
166	if (IS_ERR(kern_buff))
167		return PTR_ERR(kern_buff);
168	tmp_buff = kern_buff;
169
170	/* Read the API name from a user request */
171	pm_api_req = strsep(&kern_buff, " ");
172
173	ret = get_pm_api_id(pm_api_req, &pm_id);
174	if (ret < 0)
175		goto err;
176
177	/* Read node_id and arguments from the PM-API request */
178	pm_api_req = strsep(&kern_buff, " ");
179	while ((i < ARRAY_SIZE(pm_api_arg)) && pm_api_req) {
180		pm_api_arg[i++] = zynqmp_pm_argument_value(pm_api_req);
181		pm_api_req = strsep(&kern_buff, " ");
182	}
183
184	ret = process_api_request(pm_id, pm_api_arg, pm_api_ret);
185
186err:
187	kfree(tmp_buff);
188	if (ret)
189		return ret;
190
191	return len;
192}
193
194/**
195 * zynqmp_pm_debugfs_api_read() - debugfs read function
196 * @file:	User file
197 * @ptr:	Requested pm_api_version string
198 * @len:	Length of the userspace buffer
199 * @off:	Offset within the file
200 *
201 * Return: Length of the version string on success
202 *	   else error code
203 */
204static ssize_t zynqmp_pm_debugfs_api_read(struct file *file, char __user *ptr,
205					  size_t len, loff_t *off)
206{
207	return simple_read_from_buffer(ptr, len, off, debugfs_buf,
208				       strlen(debugfs_buf));
209}
210
211/* Setup debugfs fops */
212static const struct file_operations fops_zynqmp_pm_dbgfs = {
213	.owner = THIS_MODULE,
214	.write = zynqmp_pm_debugfs_api_write,
215	.read = zynqmp_pm_debugfs_api_read,
216};
217
218/**
219 * zynqmp_pm_api_debugfs_init - Initialize debugfs interface
220 *
221 * Return:	None
222 */
223void zynqmp_pm_api_debugfs_init(void)
224{
225	/* Initialize debugfs interface */
226	firmware_debugfs_root = debugfs_create_dir("zynqmp-firmware", NULL);
227	debugfs_create_file("pm", 0660, firmware_debugfs_root, NULL,
228			    &fops_zynqmp_pm_dbgfs);
229}
230
231/**
232 * zynqmp_pm_api_debugfs_exit - Remove debugfs interface
233 *
234 * Return:	None
235 */
236void zynqmp_pm_api_debugfs_exit(void)
237{
238	debugfs_remove_recursive(firmware_debugfs_root);
239}