Re: [PATCH v2.1] x86/amd_node, platform/x86/amd/hsmp: Have HSMP use SMN through AMD_NODE

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

On Thu, 12 Dec 2024, Yazen Ghannam wrote:

> 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>
> ---
> 
> Notes:
>     Link:
>     https://lore.kernel.org/20241206161210.163701-15-yazen.ghannam@amd.com
>     
>     v2->v2.1:
>     * Include static_assert() and comment for sysfs attributes.
>     
>     v1->v2:
>     * Rebase on recent HSMP rework.
> 
>  arch/x86/include/asm/amd_nb.h         |  1 -
>  arch/x86/include/asm/amd_node.h       |  3 +++
>  arch/x86/kernel/amd_nb.c              |  1 -
>  arch/x86/kernel/amd_node.c            |  9 +++++++
>  drivers/platform/x86/amd/hsmp/Kconfig |  2 +-
>  drivers/platform/x86/amd/hsmp/acpi.c  |  7 +++---
>  drivers/platform/x86/amd/hsmp/hsmp.c  |  1 -
>  drivers/platform/x86/amd/hsmp/hsmp.h  |  3 ---
>  drivers/platform/x86/amd/hsmp/plat.c  | 35 +++++++++------------------
>  9 files changed, 28 insertions(+), 34 deletions(-)
> 
> diff --git a/arch/x86/include/asm/amd_nb.h b/arch/x86/include/asm/amd_nb.h
> index 4c4efb93045e..adfa0854cf2d 100644
> --- 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
> index 113ad3e8ee40..5fe9c6537434 100644
> --- a/arch/x86/include/asm/amd_node.h
> +++ b/arch/x86/include/asm/amd_node.h
> @@ -33,4 +33,7 @@ static inline u16 amd_num_nodes(void)
>  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);
> +
>  #endif /*_ASM_X86_AMD_NODE_H_*/
> diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
> index 2729e99806ec..3a20312062af 100644
> --- 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);
>  		node_to_amd_nb(i)->link = amd_node_get_func(i, 4);
>  	}
> diff --git a/arch/x86/kernel/amd_node.c b/arch/x86/kernel/amd_node.c
> index d2ec7fd555c5..65045f223c10 100644
> --- 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
> index 7d10d4462a45..d6f7a62d55b5 100644
> --- 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
> index e981d45e1c12..28565ca78afd 100644
> --- 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
> index 227b4ad4a51a..e04c613ad5d6 100644
> --- 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
> index e852f0a947e4..af8b21f821d6 100644
> --- 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
> index a61f815c9f80..32921092b0c8 100644
> --- a/drivers/platform/x86/amd/hsmp/plat.c
> +++ b/drivers/platform/x86/amd/hsmp/plat.c
> @@ -10,7 +10,6 @@
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>  
>  #include <asm/amd_hsmp.h>
> -#include <asm/amd_nb.h>
>  
>  #include <linux/device.h>
>  #include <linux/module.h>
> @@ -18,6 +17,8 @@
>  #include <linux/platform_device.h>
>  #include <linux/sysfs.h>
>  
> +#include <asm/amd_node.h>
> +
>  #include "hsmp.h"
>  
>  #define DRIVER_NAME		"amd_hsmp"
> @@ -34,28 +35,12 @@
>  #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 +80,12 @@ 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);

Please also add the #include for it.

-- 
 i.

>  #define HSMP_BIN_ATTR(index, _list)					\
>  static struct bin_attribute attr##index = {				\
>  	.attr = { .name = HSMP_METRICS_TABLE_NAME, .mode = 0444},	\
> @@ -159,10 +149,7 @@ 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 +292,11 @@ 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);
>