x86/amd_node, platform/x86/amd/hsmp: Have HSMP use SMN through AMD_NODE

The HSMP interface is just an SMN interface with different offsets. Define an HSMP wrapper in the SMN code and have the HSMP platform driver use that rather than a local solution. Also, remove the "root" member from AMD_NB, since there are no more users of it. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Carlos Bilbao <carlos.bilbao@kernel.org> Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20250130-wip-x86-amd-nb-cleanup-v4-1-b5cc997e471b@amd.com
mariux64 · Feb 17, 2025 · 735049b · 735049b
1 parent e3cd859
commit 735049b
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Showing 9 changed files with 39 additions and 34 deletions.
diff --git a/arch/x86/include/asm/amd_nb.h b/arch/x86/include/asm/amd_nb.h
@@ -27,7 +27,6 @@ struct amd_l3_cache {
 };
 
 struct amd_northbridge {
-	struct pci_dev *root;
 	struct pci_dev *misc;
 	struct pci_dev *link;
 	struct amd_l3_cache l3_cache;

diff --git a/arch/x86/include/asm/amd_node.h b/arch/x86/include/asm/amd_node.h
@@ -30,7 +30,20 @@ static inline u16 amd_num_nodes(void)
 	return topology_amd_nodes_per_pkg() * topology_max_packages();
 }
 
+#ifdef CONFIG_AMD_NODE
 int __must_check amd_smn_read(u16 node, u32 address, u32 *value);
 int __must_check amd_smn_write(u16 node, u32 address, u32 value);
 
+/* Should only be used by the HSMP driver. */
+int __must_check amd_smn_hsmp_rdwr(u16 node, u32 address, u32 *value, bool write);
+#else
+static inline int __must_check amd_smn_read(u16 node, u32 address, u32 *value) { return -ENODEV; }
+static inline int __must_check amd_smn_write(u16 node, u32 address, u32 value) { return -ENODEV; }
+
+static inline int __must_check amd_smn_hsmp_rdwr(u16 node, u32 address, u32 *value, bool write)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_AMD_NODE */
+
 #endif /*_ASM_X86_AMD_NODE_H_*/
diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
@@ -73,7 +73,6 @@ static int amd_cache_northbridges(void)
 	amd_northbridges.nb = nb;
 
 	for (i = 0; i < amd_northbridges.num; i++) {
-		node_to_amd_nb(i)->root = amd_node_get_root(i);
 		node_to_amd_nb(i)->misc = amd_node_get_func(i, 3);
 
 		/*

diff --git a/arch/x86/kernel/amd_node.c b/arch/x86/kernel/amd_node.c
@@ -97,6 +97,9 @@ static DEFINE_MUTEX(smn_mutex);
 #define SMN_INDEX_OFFSET	0x60
 #define SMN_DATA_OFFSET		0x64
 
+#define HSMP_INDEX_OFFSET	0xc4
+#define HSMP_DATA_OFFSET	0xc8
+
 /*
  * SMN accesses may fail in ways that are difficult to detect here in the called
  * functions amd_smn_read() and amd_smn_write(). Therefore, callers must do
@@ -179,6 +182,12 @@ int __must_check amd_smn_write(u16 node, u32 address, u32 value)
 }
 EXPORT_SYMBOL_GPL(amd_smn_write);
 
+int __must_check amd_smn_hsmp_rdwr(u16 node, u32 address, u32 *value, bool write)
+{
+	return __amd_smn_rw(HSMP_INDEX_OFFSET, HSMP_DATA_OFFSET, node, address, value, write);
+}
+EXPORT_SYMBOL_GPL(amd_smn_hsmp_rdwr);
+
 static int amd_cache_roots(void)
 {
 	u16 node, num_nodes = amd_num_nodes();

diff --git a/drivers/platform/x86/amd/hsmp/Kconfig b/drivers/platform/x86/amd/hsmp/Kconfig
@@ -7,7 +7,7 @@ config AMD_HSMP
 	tristate
 
 menu "AMD HSMP Driver"
-	depends on AMD_NB || COMPILE_TEST
+	depends on AMD_NODE || COMPILE_TEST
 
 config AMD_HSMP_ACPI
 	tristate "AMD HSMP ACPI device driver"

diff --git a/drivers/platform/x86/amd/hsmp/acpi.c b/drivers/platform/x86/amd/hsmp/acpi.c
@@ -10,7 +10,6 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <asm/amd_hsmp.h>
-#include <asm/amd_nb.h>
 
 #include <linux/acpi.h>
 #include <linux/device.h>
@@ -24,6 +23,8 @@
 
 #include <uapi/asm-generic/errno-base.h>
 
+#include <asm/amd_node.h>
+
 #include "hsmp.h"
 
 #define DRIVER_NAME		"amd_hsmp"
@@ -321,8 +322,8 @@ static int hsmp_acpi_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	if (!hsmp_pdev->is_probed) {
-		hsmp_pdev->num_sockets = amd_nb_num();
-		if (hsmp_pdev->num_sockets == 0 || hsmp_pdev->num_sockets > MAX_AMD_SOCKETS)
+		hsmp_pdev->num_sockets = amd_num_nodes();
+		if (hsmp_pdev->num_sockets == 0 || hsmp_pdev->num_sockets > MAX_AMD_NUM_NODES)
 			return -ENODEV;
 
 		hsmp_pdev->sock = devm_kcalloc(&pdev->dev, hsmp_pdev->num_sockets,

diff --git a/drivers/platform/x86/amd/hsmp/hsmp.c b/drivers/platform/x86/amd/hsmp/hsmp.c
@@ -8,7 +8,6 @@
  */
 
 #include <asm/amd_hsmp.h>
-#include <asm/amd_nb.h>
 
 #include <linux/acpi.h>
 #include <linux/delay.h>

diff --git a/drivers/platform/x86/amd/hsmp/hsmp.h b/drivers/platform/x86/amd/hsmp/hsmp.h
@@ -21,8 +21,6 @@
 
 #define HSMP_ATTR_GRP_NAME_SIZE	10
 
-#define MAX_AMD_SOCKETS 8
-
 #define HSMP_CDEV_NAME		"hsmp_cdev"
 #define HSMP_DEVNODE_NAME	"hsmp"
 
@@ -41,7 +39,6 @@ struct hsmp_socket {
 	void __iomem *virt_base_addr;
 	struct semaphore hsmp_sem;
 	char name[HSMP_ATTR_GRP_NAME_SIZE];
-	struct pci_dev *root;
 	struct device *dev;
 	u16 sock_ind;
 	int (*amd_hsmp_rdwr)(struct hsmp_socket *sock, u32 off, u32 *val, bool rw);

diff --git a/drivers/platform/x86/amd/hsmp/plat.c b/drivers/platform/x86/amd/hsmp/plat.c
@@ -10,14 +10,16 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <asm/amd_hsmp.h>
-#include <asm/amd_nb.h>
 
+#include <linux/build_bug.h>
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/sysfs.h>
 
+#include <asm/amd_node.h>
+
 #include "hsmp.h"
 
 #define DRIVER_NAME		"amd_hsmp"
@@ -34,28 +36,12 @@
 #define SMN_HSMP_MSG_RESP	0x0010980
 #define SMN_HSMP_MSG_DATA	0x00109E0
 
-#define HSMP_INDEX_REG		0xc4
-#define HSMP_DATA_REG		0xc8
-
 static struct hsmp_plat_device *hsmp_pdev;
 
 static int amd_hsmp_pci_rdwr(struct hsmp_socket *sock, u32 offset,
 			     u32 *value, bool write)
 {
-	int ret;
-
-	if (!sock->root)
-		return -ENODEV;
-
-	ret = pci_write_config_dword(sock->root, HSMP_INDEX_REG,
-				     sock->mbinfo.base_addr + offset);
-	if (ret)
-		return ret;
-
-	ret = (write ? pci_write_config_dword(sock->root, HSMP_DATA_REG, *value)
-		     : pci_read_config_dword(sock->root, HSMP_DATA_REG, value));
-
-	return ret;
+	return amd_smn_hsmp_rdwr(sock->sock_ind, sock->mbinfo.base_addr + offset, value, write);
 }
 
 static ssize_t hsmp_metric_tbl_plat_read(struct file *filp, struct kobject *kobj,
@@ -95,7 +81,12 @@ static umode_t hsmp_is_sock_attr_visible(struct kobject *kobj,
  * Static array of 8 + 1(for NULL) elements is created below
  * to create sysfs groups for sockets.
  * is_bin_visible function is used to show / hide the necessary groups.
+ *
+ * Validate the maximum number against MAX_AMD_NUM_NODES. If this changes,
+ * then the attributes and groups below must be adjusted.
  */
+static_assert(MAX_AMD_NUM_NODES == 8);
+
 #define HSMP_BIN_ATTR(index, _list)					\
 static const struct bin_attribute attr##index = {			\
 	.attr = { .name = HSMP_METRICS_TABLE_NAME, .mode = 0444},	\
@@ -159,10 +150,7 @@ static int init_platform_device(struct device *dev)
 	int ret, i;
 
 	for (i = 0; i < hsmp_pdev->num_sockets; i++) {
-		if (!node_to_amd_nb(i))
-			return -ENODEV;
 		sock = &hsmp_pdev->sock[i];
-		sock->root			= node_to_amd_nb(i)->root;
 		sock->sock_ind			= i;
 		sock->dev			= dev;
 		sock->mbinfo.base_addr		= SMN_HSMP_BASE;
@@ -305,11 +293,11 @@ static int __init hsmp_plt_init(void)
 		return -ENOMEM;
 
 	/*
-	 * amd_nb_num() returns number of SMN/DF interfaces present in the system
+	 * amd_num_nodes() returns number of SMN/DF interfaces present in the system
 	 * if we have N SMN/DF interfaces that ideally means N sockets
 	 */
-	hsmp_pdev->num_sockets = amd_nb_num();
-	if (hsmp_pdev->num_sockets == 0 || hsmp_pdev->num_sockets > MAX_AMD_SOCKETS)
+	hsmp_pdev->num_sockets = amd_num_nodes();
+	if (hsmp_pdev->num_sockets == 0 || hsmp_pdev->num_sockets > MAX_AMD_NUM_NODES)
 		return ret;
 
 	ret = platform_driver_register(&amd_hsmp_driver);