Re: [PATCH 14/16] x86/amd_smn, platform/x86/amd/hsmp: Have HSMP use SMN

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

On Wed, 23 Oct 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>
> ---
>  arch/x86/include/asm/amd_nb.h    |  1 -
>  arch/x86/include/asm/amd_smn.h   |  3 +++
>  arch/x86/kernel/amd_nb.c         |  1 -
>  arch/x86/kernel/amd_smn.c        |  9 +++++++++
>  drivers/platform/x86/amd/Kconfig |  2 +-
>  drivers/platform/x86/amd/hsmp.c  | 32 +++++---------------------------
>  6 files changed, 18 insertions(+), 30 deletions(-)
> 
> diff --git a/arch/x86/include/asm/amd_nb.h b/arch/x86/include/asm/amd_nb.h
> index 55c03d3495bc..cbe31e316e39 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_smn.h b/arch/x86/include/asm/amd_smn.h
> index 6850de69f863..f0eb12859c42 100644
> --- a/arch/x86/include/asm/amd_smn.h
> +++ b/arch/x86/include/asm/amd_smn.h
> @@ -8,4 +8,7 @@
>  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_SMN_H */
> diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
> index 10cdeddeda02..4c22317a6dfe 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_smn.c b/arch/x86/kernel/amd_smn.c
> index 997fd3edd9c0..527dda8e3a2b 100644
> --- a/arch/x86/kernel/amd_smn.c
> +++ b/arch/x86/kernel/amd_smn.c
> @@ -18,6 +18,9 @@ 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
> @@ -100,6 +103,12 @@ 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/Kconfig b/drivers/platform/x86/amd/Kconfig
> index f88682d36447..e100b315c62b 100644
> --- a/drivers/platform/x86/amd/Kconfig
> +++ b/drivers/platform/x86/amd/Kconfig
> @@ -8,7 +8,7 @@ source "drivers/platform/x86/amd/pmc/Kconfig"
>  
>  config AMD_HSMP
>  	tristate "AMD HSMP Driver"
> -	depends on AMD_NB && X86_64 && ACPI
> +	depends on AMD_SMN && X86_64 && ACPI
>  	help
>  	  The driver provides a way for user space tools to monitor and manage
>  	  system management functionality on EPYC server CPUs from AMD.
> diff --git a/drivers/platform/x86/amd/hsmp.c b/drivers/platform/x86/amd/hsmp.c
> index 8fcf38eed7f0..544efb0255c0 100644
> --- a/drivers/platform/x86/amd/hsmp.c
> +++ b/drivers/platform/x86/amd/hsmp.c

FYI, there has been major restructuring done for this driver in 
pdx86/for-next.

-- 
 i.

> @@ -10,7 +10,7 @@
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>  
>  #include <asm/amd_hsmp.h>
> -#include <asm/amd_nb.h>
> +#include <asm/amd_smn.h>
>  #include <linux/delay.h>
>  #include <linux/io.h>
>  #include <linux/miscdevice.h>
> @@ -48,9 +48,6 @@
>  #define SMN_HSMP_MSG_RESP	0x0010980
>  #define SMN_HSMP_MSG_DATA	0x00109E0
>  
> -#define HSMP_INDEX_REG		0xc4
> -#define HSMP_DATA_REG		0xc8
> -
>  #define HSMP_CDEV_NAME		"hsmp_cdev"
>  #define HSMP_DEVNODE_NAME	"hsmp"
>  #define HSMP_METRICS_TABLE_NAME	"metrics_bin"
> @@ -62,8 +59,6 @@
>  #define MSG_ARGOFF_STR		"MsgArgOffset"
>  #define MSG_RESPOFF_STR		"MsgRspOffset"
>  
> -#define MAX_AMD_SOCKETS 8
> -
>  struct hsmp_mbaddr_info {
>  	u32 base_addr;
>  	u32 msg_id_off;
> @@ -79,7 +74,6 @@ 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;
>  };
> @@ -98,20 +92,7 @@ static struct hsmp_plat_device plat_dev;
>  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 void amd_hsmp_acpi_rdwr(struct hsmp_socket *sock, u32 offset,
> @@ -749,10 +730,7 @@ static int init_platform_device(struct device *dev)
>  	int ret, i;
>  
>  	for (i = 0; i < plat_dev.num_sockets; i++) {
> -		if (!node_to_amd_nb(i))
> -			return -ENODEV;
>  		sock = &plat_dev.sock[i];
> -		sock->root			= node_to_amd_nb(i)->root;
>  		sock->sock_ind			= i;
>  		sock->dev			= dev;
>  		sock->mbinfo.base_addr		= SMN_HSMP_BASE;
> @@ -946,11 +924,11 @@ static int __init hsmp_plt_init(void)
>  	int ret = -ENODEV;
>  
>  	/*
> -	 * 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
>  	 */
> -	plat_dev.num_sockets = amd_nb_num();
> -	if (plat_dev.num_sockets == 0 || plat_dev.num_sockets > MAX_AMD_SOCKETS)
> +	plat_dev.num_sockets = amd_num_nodes();
> +	if (plat_dev.num_sockets == 0 || plat_dev.num_sockets > MAX_AMD_NUM_NODES)
>  		return ret;
>  
>  	ret = platform_driver_register(&amd_hsmp_driver);
>