1 files changed, 425 insertions, 0 deletions
diff --git a/drivers/platform/x86/amd/hsmp.c b/drivers/platform/x86/amd/hsmp.c
new file mode 100644
index 000000000000..a0c54b838c11
--- /dev/null
+++ b/drivers/platform/x86/amd/hsmp.c
@@ -0,0 +1,425 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD HSMP Platform Driver
+ * Copyright (c) 2022, AMD.
+ * All Rights Reserved.
+ *
+ * This file provides a device implementation for HSMP interface
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <asm/amd_hsmp.h>
+#include <asm/amd_nb.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/semaphore.h>
+
+#define DRIVER_NAME		"amd_hsmp"
+#define DRIVER_VERSION		"1.0"
+
+/* HSMP Status / Error codes */
+#define HSMP_STATUS_NOT_READY	0x00
+#define HSMP_STATUS_OK		0x01
+#define HSMP_ERR_INVALID_MSG	0xFE
+#define HSMP_ERR_INVALID_INPUT	0xFF
+
+/* Timeout in millsec */
+#define HSMP_MSG_TIMEOUT	100
+#define HSMP_SHORT_SLEEP	1
+
+#define HSMP_WR			true
+#define HSMP_RD			false
+
+/*
+ * To access specific HSMP mailbox register, s/w writes the SMN address of HSMP mailbox
+ * register into the SMN_INDEX register, and reads/writes the SMN_DATA reg.
+ * Below are required SMN address for HSMP Mailbox register offsets in SMU address space
+ */
+#define SMN_HSMP_MSG_ID		0x3B10534
+#define SMN_HSMP_MSG_RESP	0x3B10980
+#define SMN_HSMP_MSG_DATA	0x3B109E0
+
+#define HSMP_INDEX_REG		0xc4
+#define HSMP_DATA_REG		0xc8
+
+static struct semaphore *hsmp_sem;
+
+static struct miscdevice hsmp_device;
+
+static int amd_hsmp_rdwr(struct pci_dev *root, u32 address,
+			 u32 *value, bool write)
+{
+	int ret;
+
+	ret = pci_write_config_dword(root, HSMP_INDEX_REG, address);
+	if (ret)
+		return ret;
+
+	ret = (write ? pci_write_config_dword(root, HSMP_DATA_REG, *value)
+		     : pci_read_config_dword(root, HSMP_DATA_REG, value));
+
+	return ret;
+}
+
+/*
+ * Send a message to the HSMP port via PCI-e config space registers.
+ *
+ * The caller is expected to zero out any unused arguments.
+ * If a response is expected, the number of response words should be greater than 0.
+ *
+ * Returns 0 for success and populates the requested number of arguments.
+ * Returns a negative error code for failure.
+ */
+static int __hsmp_send_message(struct pci_dev *root, struct hsmp_message *msg)
+{
+	unsigned long timeout, short_sleep;
+	u32 mbox_status;
+	u32 index;
+	int ret;
+
+	/* Clear the status register */
+	mbox_status = HSMP_STATUS_NOT_READY;
+	ret = amd_hsmp_rdwr(root, SMN_HSMP_MSG_RESP, &mbox_status, HSMP_WR);
+	if (ret) {
+		pr_err("Error %d clearing mailbox status register\n", ret);
+		return ret;
+	}
+
+	index = 0;
+	/* Write any message arguments */
+	while (index < msg->num_args) {
+		ret = amd_hsmp_rdwr(root, SMN_HSMP_MSG_DATA + (index << 2),
+				    &msg->args[index], HSMP_WR);
+		if (ret) {
+			pr_err("Error %d writing message argument %d\n", ret, index);
+			return ret;
+		}
+		index++;
+	}
+
+	/* Write the message ID which starts the operation */
+	ret = amd_hsmp_rdwr(root, SMN_HSMP_MSG_ID, &msg->msg_id, HSMP_WR);
+	if (ret) {
+		pr_err("Error %d writing message ID %u\n", ret, msg->msg_id);
+		return ret;
+	}
+
+	/*
+	 * Depending on when the trigger write completes relative to the SMU
+	 * firmware 1 ms cycle, the operation may take from tens of us to 1 ms
+	 * to complete. Some operations may take more. Therefore we will try
+	 * a few short duration sleeps and switch to long sleeps if we don't
+	 * succeed quickly.
+	 */
+	short_sleep = jiffies + msecs_to_jiffies(HSMP_SHORT_SLEEP);
+	timeout	= jiffies + msecs_to_jiffies(HSMP_MSG_TIMEOUT);
+
+	while (time_before(jiffies, timeout)) {
+		ret = amd_hsmp_rdwr(root, SMN_HSMP_MSG_RESP, &mbox_status, HSMP_RD);
+		if (ret) {
+			pr_err("Error %d reading mailbox status\n", ret);
+			return ret;
+		}
+
+		if (mbox_status != HSMP_STATUS_NOT_READY)
+			break;
+		if (time_before(jiffies, short_sleep))
+			usleep_range(50, 100);
+		else
+			usleep_range(1000, 2000);
+	}
+
+	if (unlikely(mbox_status == HSMP_STATUS_NOT_READY)) {
+		return -ETIMEDOUT;
+	} else if (unlikely(mbox_status == HSMP_ERR_INVALID_MSG)) {
+		return -ENOMSG;
+	} else if (unlikely(mbox_status == HSMP_ERR_INVALID_INPUT)) {
+		return -EINVAL;
+	} else if (unlikely(mbox_status != HSMP_STATUS_OK)) {
+		pr_err("Message ID %u unknown failure (status = 0x%X)\n",
+		       msg->msg_id, mbox_status);
+		return -EIO;
+	}
+
+	/*
+	 * SMU has responded OK. Read response data.
+	 * SMU reads the input arguments from eight 32 bit registers starting
+	 * from SMN_HSMP_MSG_DATA and writes the response data to the same
+	 * SMN_HSMP_MSG_DATA address.
+	 * We copy the response data if any, back to the args[].
+	 */
+	index = 0;
+	while (index < msg->response_sz) {
+		ret = amd_hsmp_rdwr(root, SMN_HSMP_MSG_DATA + (index << 2),
+				    &msg->args[index], HSMP_RD);
+		if (ret) {
+			pr_err("Error %d reading response %u for message ID:%u\n",
+			       ret, index, msg->msg_id);
+			break;
+		}
+		index++;
+	}
+
+	return ret;
+}
+
+static int validate_message(struct hsmp_message *msg)
+{
+	/* msg_id against valid range of message IDs */
+	if (msg->msg_id < HSMP_TEST || msg->msg_id >= HSMP_MSG_ID_MAX)
+		return -ENOMSG;
+
+	/* msg_id is a reserved message ID */
+	if (hsmp_msg_desc_table[msg->msg_id].type == HSMP_RSVD)
+		return -ENOMSG;
+
+	/* num_args and response_sz against the HSMP spec */
+	if (msg->num_args != hsmp_msg_desc_table[msg->msg_id].num_args ||
+	    msg->response_sz != hsmp_msg_desc_table[msg->msg_id].response_sz)
+		return -EINVAL;
+
+	return 0;
+}
+
+int hsmp_send_message(struct hsmp_message *msg)
+{
+	struct amd_northbridge *nb;
+	int ret;
+
+	if (!msg)
+		return -EINVAL;
+
+	nb = node_to_amd_nb(msg->sock_ind);
+	if (!nb || !nb->root)
+		return -ENODEV;
+
+	ret = validate_message(msg);
+	if (ret)
+		return ret;
+
+	/*
+	 * The time taken by smu operation to complete is between
+	 * 10us to 1ms. Sometime it may take more time.
+	 * In SMP system timeout of 100 millisecs should
+	 * be enough for the previous thread to finish the operation
+	 */
+	ret = down_timeout(&hsmp_sem[msg->sock_ind],
+			   msecs_to_jiffies(HSMP_MSG_TIMEOUT));
+	if (ret < 0)
+		return ret;
+
+	ret = __hsmp_send_message(nb->root, msg);
+
+	up(&hsmp_sem[msg->sock_ind]);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hsmp_send_message);
+
+static int hsmp_test(u16 sock_ind, u32 value)
+{
+	struct hsmp_message msg = { 0 };
+	struct amd_northbridge *nb;
+	int ret = -ENODEV;
+
+	nb = node_to_amd_nb(sock_ind);
+	if (!nb || !nb->root)
+		return ret;
+
+	/*
+	 * Test the hsmp port by performing TEST command. The test message
+	 * takes one argument and returns the value of that argument + 1.
+	 */
+	msg.msg_id	= HSMP_TEST;
+	msg.num_args	= 1;
+	msg.response_sz	= 1;
+	msg.args[0]	= value;
+	msg.sock_ind	= sock_ind;
+
+	ret = __hsmp_send_message(nb->root, &msg);
+	if (ret)
+		return ret;
+
+	/* Check the response value */
+	if (msg.args[0] != (value + 1)) {
+		pr_err("Socket %d test message failed, Expected 0x%08X, received 0x%08X\n",
+		       sock_ind, (value + 1), msg.args[0]);
+		return -EBADE;
+	}
+
+	return ret;
+}
+
+static long hsmp_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
+{
+	int __user *arguser = (int  __user *)arg;
+	struct hsmp_message msg = { 0 };
+	int ret;
+
+	if (copy_struct_from_user(&msg, sizeof(msg), arguser, sizeof(struct hsmp_message)))
+		return -EFAULT;
+
+	/*
+	 * Check msg_id is within the range of supported msg ids
+	 * i.e within the array bounds of hsmp_msg_desc_table
+	 */
+	if (msg.msg_id < HSMP_TEST || msg.msg_id >= HSMP_MSG_ID_MAX)
+		return -ENOMSG;
+
+	switch (fp->f_mode & (FMODE_WRITE | FMODE_READ)) {
+	case FMODE_WRITE:
+		/*
+		 * Device is opened in O_WRONLY mode
+		 * Execute only set/configure commands
+		 */
+		if (hsmp_msg_desc_table[msg.msg_id].type != HSMP_SET)
+			return -EINVAL;
+		break;
+	case FMODE_READ:
+		/*
+		 * Device is opened in O_RDONLY mode
+		 * Execute only get/monitor commands
+		 */
+		if (hsmp_msg_desc_table[msg.msg_id].type != HSMP_GET)
+			return -EINVAL;
+		break;
+	case FMODE_READ | FMODE_WRITE:
+		/*
+		 * Device is opened in O_RDWR mode
+		 * Execute both get/monitor and set/configure commands
+		 */
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = hsmp_send_message(&msg);
+	if (ret)
+		return ret;
+
+	if (hsmp_msg_desc_table[msg.msg_id].response_sz > 0) {
+		/* Copy results back to user for get/monitor commands */
+		if (copy_to_user(arguser, &msg, sizeof(struct hsmp_message)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+static const struct file_operations hsmp_fops = {
+	.owner		= THIS_MODULE,
+	.unlocked_ioctl	= hsmp_ioctl,
+	.compat_ioctl	= hsmp_ioctl,
+};
+
+static int hsmp_pltdrv_probe(struct platform_device *pdev)
+{
+	int i;
+
+	hsmp_sem = devm_kzalloc(&pdev->dev,
+				(amd_nb_num() * sizeof(struct semaphore)),
+				GFP_KERNEL);
+	if (!hsmp_sem)
+		return -ENOMEM;
+
+	for (i = 0; i < amd_nb_num(); i++)
+		sema_init(&hsmp_sem[i], 1);
+
+	hsmp_device.name	= "hsmp_cdev";
+	hsmp_device.minor	= MISC_DYNAMIC_MINOR;
+	hsmp_device.fops	= &hsmp_fops;
+	hsmp_device.parent	= &pdev->dev;
+	hsmp_device.nodename	= "hsmp";
+	hsmp_device.mode	= 0644;
+
+	return misc_register(&hsmp_device);
+}
+
+static int hsmp_pltdrv_remove(struct platform_device *pdev)
+{
+	misc_deregister(&hsmp_device);
+
+	return 0;
+}
+
+static struct platform_driver amd_hsmp_driver = {
+	.probe		= hsmp_pltdrv_probe,
+	.remove		= hsmp_pltdrv_remove,
+	.driver		= {
+		.name	= DRIVER_NAME,
+	},
+};
+
+static struct platform_device *amd_hsmp_platdev;
+
+static int __init hsmp_plt_init(void)
+{
+	int ret = -ENODEV;
+	u16 num_sockets;
+	int i;
+
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD || boot_cpu_data.x86 < 0x19) {
+		pr_err("HSMP is not supported on Family:%x model:%x\n",
+		       boot_cpu_data.x86, boot_cpu_data.x86_model);
+		return ret;
+	}
+
+	/*
+	 * amd_nb_num() returns number of SMN/DF interfaces present in the system
+	 * if we have N SMN/DF interfaces that ideally means N sockets
+	 */
+	num_sockets = amd_nb_num();
+	if (num_sockets == 0)
+		return ret;
+
+	/* Test the hsmp interface on each socket */
+	for (i = 0; i < num_sockets; i++) {
+		ret = hsmp_test(i, 0xDEADBEEF);
+		if (ret) {
+			pr_err("HSMP is not supported on Fam:%x model:%x\n",
+			       boot_cpu_data.x86, boot_cpu_data.x86_model);
+			pr_err("Or Is HSMP disabled in BIOS ?\n");
+			return -EOPNOTSUPP;
+		}
+	}
+
+	ret = platform_driver_register(&amd_hsmp_driver);
+	if (ret)
+		return ret;
+
+	amd_hsmp_platdev = platform_device_alloc(DRIVER_NAME, -1);
+	if (!amd_hsmp_platdev) {
+		ret = -ENOMEM;
+		goto drv_unregister;
+	}
+
+	ret = platform_device_add(amd_hsmp_platdev);
+	if (ret) {
+		platform_device_put(amd_hsmp_platdev);
+		goto drv_unregister;
+	}
+
+	return 0;
+
+drv_unregister:
+	platform_driver_unregister(&amd_hsmp_driver);
+	return ret;
+}
+
+static void __exit hsmp_plt_exit(void)
+{
+	platform_device_unregister(amd_hsmp_platdev);
+	platform_driver_unregister(&amd_hsmp_driver);
+}
+
+device_initcall(hsmp_plt_init);
+module_exit(hsmp_plt_exit);
+
+MODULE_DESCRIPTION("AMD HSMP Platform Interface Driver");
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");