Message-ID: <20210902174155.7365-1-nchatrad@amd.com>
Date:   Thu, 2 Sep 2021 23:11:53 +0530
From:   Naveen Krishna Chatradhi <nchatrad@....com>
To:     <linux-hwmon@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <x86@...nel.org>
CC:     <linux@...ck-us.net>, <bp@...en8.de>, <yazen.ghannam@....com>,
        <mingo@...hat.com>, <nathan.fontenot@....com>,
        <lewis.carroll@....com>,
        Naveen Krishna Chatradhi <nchatrad@....com>,
        Ingo Molnar <mingo@...nel.org>,
        Jean Delvare <jdelvare@...e.com>
Subject: [PATCH 1/3] x86/amd_nb: Add support for HSMP mailbox access

On Fam19h server CPUs from AMD an HSMP (Host System Management Port)
mailbox interface is added to monitor and manage the CPU parameters.

Export hsmp_send_message() function which takes a socket number and
a messages structure as inputs, returns 0 on success and negative
error otherwise. The API can be used by other kernel components to
access system management features.

Eg: hwmon based k10temp driver can be modified to report power metrics

Signed-off-by: Naveen Krishna Chatradhi <nchatrad@....com>
Cc: Guenter Roeck <linux@...ck-us.net>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Jean Delvare <jdelvare@...e.com>
Cc: x86-ml <x86@...nel.org>
Cc: Yazen Ghannam <yazen.ghannam@....com>
---
 arch/x86/include/asm/amd_nb.h |  40 +++++++
 arch/x86/kernel/amd_nb.c      | 217 ++++++++++++++++++++++++++++++++++
 2 files changed, 257 insertions(+)

diff --git a/arch/x86/include/asm/amd_nb.h b/arch/x86/include/asm/amd_nb.h
index 455066a06f60..2640429114ee 100644
--- a/arch/x86/include/asm/amd_nb.h
+++ b/arch/x86/include/asm/amd_nb.h
@@ -66,6 +66,7 @@ struct amd_northbridge {
 	struct pci_dev *link;
 	struct amd_l3_cache l3_cache;
 	struct threshold_bank *bank4;
+	struct semaphore hsmp_sem_lock;
 };
 
 struct amd_northbridge_info {
@@ -77,6 +78,7 @@ struct amd_northbridge_info {
 #define AMD_NB_GART			BIT(0)
 #define AMD_NB_L3_INDEX_DISABLE		BIT(1)
 #define AMD_NB_L3_PARTITIONING		BIT(2)
+#define AMD_NB_HSMP			BIT(3)
 
 #ifdef CONFIG_AMD_NB
 
@@ -123,5 +125,43 @@ static inline bool amd_gart_present(void)
 
 #endif
 
+/*
+ * HSMP Message types supported
+ */
+enum hsmp_message_ids {
+	HSMP_TEST = 1,
+	HSMP_GET_SMU_VER,
+	HSMP_GET_PROTO_VER,
+	HSMP_GET_SOCKET_POWER,
+	HSMP_SET_SOCKET_POWER_LIMIT,
+	HSMP_GET_SOCKET_POWER_LIMIT,
+	HSMP_GET_SOCKET_POWER_LIMIT_MAX,
+	HSMP_SET_BOOST_LIMIT,
+	HSMP_SET_BOOST_LIMIT_SOCKET,
+	HSMP_GET_BOOST_LIMIT,
+	HSMP_GET_PROC_HOT,
+	HSMP_SET_XGMI_LINK_WIDTH,
+	HSMP_SET_DF_PSTATE,
+	HSMP_AUTO_DF_PSTATE,
+	HSMP_GET_FCLK_MCLK,
+	HSMP_GET_CCLK_THROTTLE_LIMIT,
+	HSMP_GET_C0_PERCENT,
+	HSMP_SET_NBIO_DPM_LEVEL,
+	HSMP_RESERVED,
+	HSMP_GET_DDR_BANDWIDTH,
+	HSMP_MSG_ID_MAX,
+};
+
+#define HSMP_MAX_MSG_LEN	8
+
+struct hsmp_message {
+	u32	msg_id;			/* Message ID */
+	u16	num_args;		/* Number of arguments in message */
+	u16	response_sz;		/* Number of expected response words */
+	u32	args[HSMP_MAX_MSG_LEN];	/* Argument(s) */
+	u32	response[HSMP_MAX_MSG_LEN];	/* Response word(s) */
+};
+
+int hsmp_send_message(int socket_id, struct hsmp_message *msg);
 
 #endif /* _ASM_X86_AMD_NB_H */
diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
index c92c9c774c0e..2bba59c1350e 100644
--- a/arch/x86/kernel/amd_nb.c
+++ b/arch/x86/kernel/amd_nb.c
@@ -6,6 +6,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/delay.h>
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/init.h>
@@ -29,6 +30,22 @@
 #define PCI_DEVICE_ID_AMD_19H_M40H_DF_F4 0x167d
 #define PCI_DEVICE_ID_AMD_19H_M50H_DF_F4 0x166e
 
+/*
+ * 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
+
+/* 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
+
 /* Protect the PCI config register pairs used for SMN and DF indirect access. */
 static DEFINE_MUTEX(smn_mutex);
 
@@ -108,6 +125,9 @@ const struct amd_nb_bus_dev_range amd_nb_bus_dev_ranges[] __initconst = {
 
 static struct amd_northbridge_info amd_northbridges;
 
+/* Timeout in millsec */
+#define HSMP_MSG_TIMEOUT	100
+
 u16 amd_nb_num(void)
 {
 	return amd_northbridges.num;
@@ -182,6 +202,194 @@ int amd_smn_write(u16 node, u32 address, u32 value)
 }
 EXPORT_SYMBOL_GPL(amd_smn_write);
 
+#define HSMP_WR true
+#define HSMP_RD false
+
+static int __amd_hsmp_rdwr(struct pci_dev *root, u32 address,
+			   u32 *value, bool write)
+{
+	int err;
+
+	err = pci_write_config_dword(root, 0xc4, address);
+	if (err) {
+		pr_warn("Error programming SMN address 0x%x.\n", address);
+		return err;
+	}
+
+	err = (write ? pci_write_config_dword(root, 0xc8, *value)
+		     : pci_read_config_dword(root, 0xc8, value));
+	if (err)
+		pr_warn("Error %s SMN address 0x%x.\n",
+			(write ? "writing to" : "reading from"), address);
+
+	return err;
+}
+
+/*
+ * 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)
+{
+	u64 timeout = HSMP_MSG_TIMEOUT;
+	u32 mbox_status;
+	u32 arg_num;
+	int err;
+
+	/* Clear the status register */
+	mbox_status = HSMP_STATUS_NOT_READY;
+	err = __amd_hsmp_rdwr(root, SMN_HSMP_MSG_RESP, &mbox_status, HSMP_WR);
+	if (err) {
+		pr_err("Error %d clearing mailbox status register.\n", err);
+		return err;
+	}
+
+	arg_num = 0;
+	/* Write any message arguments */
+	while (arg_num < msg->num_args) {
+		err = __amd_hsmp_rdwr(root, SMN_HSMP_MSG_DATA + (arg_num << 2),
+				      &msg->args[arg_num], HSMP_WR);
+		if (err) {
+			pr_err("Error %d writing message argument %d\n",
+			       err, arg_num);
+			return err;
+		}
+		arg_num++;
+	}
+
+	/* Write the message ID which starts the operation */
+	err = __amd_hsmp_rdwr(root, SMN_HSMP_MSG_ID, &msg->msg_id, HSMP_WR);
+	if (err) {
+		pr_err("Error %d writing message ID %u\n", err, msg->msg_id);
+		return err;
+	}
+
+	/*
+	 * 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.
+	 */
+	do {
+		if (likely(timeout > 90))
+			usleep_range(50, 100);
+		else
+			usleep_range(100, 500);
+
+		err = __amd_hsmp_rdwr(root, SMN_HSMP_MSG_RESP, &mbox_status, HSMP_RD);
+		if (err) {
+			pr_err("Error %d reading mailbox status\n", err);
+			return err;
+		}
+
+		if (mbox_status != HSMP_STATUS_NOT_READY)
+			break;
+
+	} while (--timeout);
+
+	if (unlikely(mbox_status == HSMP_ERR_INVALID_MSG)) {
+		pr_err("Invalid message ID %u\n", msg->msg_id);
+		err = -ENOMSG;
+		return err;
+	} else if (unlikely(mbox_status == HSMP_ERR_INVALID_INPUT)) {
+		pr_err("Invalid arguments for %d\n", msg->msg_id);
+		err = -EINVAL;
+		return err;
+	} else if (unlikely(mbox_status != HSMP_STATUS_OK)) {
+		pr_err("Message ID %u unknown failure (status = 0x%X), timedout\n",
+		       msg->msg_id, mbox_status);
+		err = -ETIMEDOUT;
+		return err;
+	}
+
+	/* SMU has responded OK. Read response data */
+	arg_num = 0;
+	while (arg_num < msg->response_sz) {
+		err = __amd_hsmp_rdwr(root, SMN_HSMP_MSG_DATA + (arg_num << 2),
+				      &msg->response[arg_num], HSMP_RD);
+		if (err) {
+			pr_err("Error %d reading response %u for message ID:%u\n",
+			       err, arg_num, msg->msg_id);
+			break;
+		}
+		arg_num++;
+	}
+
+	return err;
+}
+
+/* Verify the HSMP test message */
+static bool amd_hsmp_support(void)
+{
+	struct hsmp_message msg = { 0 };
+	int err = 0;
+	struct pci_dev *root;
+
+	/*
+	 * Check HSMP support on socket 0. the test message takes one argument
+	 * and returns the value of that argument + 1.
+	 */
+	root = node_to_amd_nb(0)->root;
+	if (!root)
+		return false;
+
+	msg.args[0]     = 0xDEADBEEF;
+	msg.response_sz = 1;
+	msg.msg_id	= HSMP_TEST;
+	msg.num_args	= 1;
+
+	err = __hsmp_send_message(root, &msg);
+	if (err)
+		return false;
+
+	if (msg.response[0] != msg.args[0] + 1)
+		return false;
+
+	return true;
+}
+
+int hsmp_send_message(int node, struct hsmp_message *msg)
+{
+	struct pci_dev *root;
+	int err;
+
+	if (!amd_nb_has_feature(AMD_NB_HSMP))
+		return -ENODEV;
+
+	root = node_to_amd_nb(node)->root;
+	if (!root || !msg)
+		return -ENODEV;
+
+	if (msg->msg_id < HSMP_TEST || msg->msg_id >= HSMP_MSG_ID_MAX)
+		return -EINVAL;
+
+	if (msg->num_args > HSMP_MAX_MSG_LEN || msg->response_sz > HSMP_MAX_MSG_LEN)
+		return -EINVAL;
+
+	/*
+	 * 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
+	 */
+	err = down_timeout(&(node_to_amd_nb(node)->hsmp_sem_lock),
+			   msecs_to_jiffies(HSMP_MSG_TIMEOUT));
+	if (err < 0)
+		return err;
+
+	err = __hsmp_send_message(root, msg);
+	up(&(node_to_amd_nb(node)->hsmp_sem_lock));
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(hsmp_send_message);
+
 /*
  * Data Fabric Indirect Access uses FICAA/FICAD.
  *
@@ -307,6 +515,15 @@ int amd_cache_northbridges(void)
 	if (amd_gart_present())
 		amd_northbridges.flags |= AMD_NB_GART;
 
+	if (boot_cpu_data.x86 >= 0x19 && amd_hsmp_support()) {
+		amd_northbridges.flags |= AMD_NB_HSMP;
+
+		/* Protect the PCI config register pairs used for HSMP mailbox access, */
+		/* by initialising  semaphore for each socket */
+		for (i = 0; i < amd_northbridges.num; i++)
+			sema_init(&(node_to_amd_nb(i)->hsmp_sem_lock), 1);
+	}
+
 	/*
 	 * Check for L3 cache presence.
 	 */
-- 
2.17.1

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