From cf141287b77485ed7624ac1756b85cc801748c7c Mon Sep 17 00:00:00 2001 From: Akshay Gupta Date: Mon, 28 Apr 2025 06:30:33 +0000 Subject: [PATCH] misc: amd-sbi: Add support for register xfer - Provide user register access over IOCTL. Both register read and write are supported. - APML interface does not provide a synchronization method. By defining, a register access path, we use APML modules and library for all APML transactions. Without having to use external tools such as i2c-tools, which may cause race conditions. Reviewed-by: Naveen Krishna Chatradhi Signed-off-by: Akshay Gupta Link: https://lore.kernel.org/r/20250428063034.2145566-10-akshay.gupta@amd.com Signed-off-by: Greg Kroah-Hartman --- drivers/misc/amd-sbi/rmi-core.c | 29 +++++++++++++++++++++++++++++ include/uapi/misc/amd-apml.h | 31 +++++++++++++++++++++++++++++++ 2 files changed, 60 insertions(+) diff --git a/drivers/misc/amd-sbi/rmi-core.c b/drivers/misc/amd-sbi/rmi-core.c index 171d6e8713734..b653a21a909ef 100644 --- a/drivers/misc/amd-sbi/rmi-core.c +++ b/drivers/misc/amd-sbi/rmi-core.c @@ -350,6 +350,33 @@ exit_unlock: return ret; } +static int apml_rmi_reg_xfer(struct sbrmi_data *data, + struct apml_reg_xfer_msg __user *arg) +{ + struct apml_reg_xfer_msg msg = { 0 }; + unsigned int data_read; + int ret; + + /* Copy the structure from user */ + if (copy_from_user(&msg, arg, sizeof(struct apml_reg_xfer_msg))) + return -EFAULT; + + mutex_lock(&data->lock); + if (msg.rflag) { + ret = regmap_read(data->regmap, msg.reg_addr, &data_read); + if (!ret) + msg.data_in_out = data_read; + } else { + ret = regmap_write(data->regmap, msg.reg_addr, msg.data_in_out); + } + + mutex_unlock(&data->lock); + + if (msg.rflag && !ret) + return copy_to_user(arg, &msg, sizeof(struct apml_reg_xfer_msg)); + return ret; +} + static int apml_mailbox_xfer(struct sbrmi_data *data, struct apml_mbox_msg __user *arg) { struct apml_mbox_msg msg = { 0 }; @@ -414,6 +441,8 @@ static long sbrmi_ioctl(struct file *fp, unsigned int cmd, unsigned long arg) return apml_cpuid_xfer(data, argp); case SBRMI_IOCTL_MCAMSR_CMD: return apml_mcamsr_xfer(data, argp); + case SBRMI_IOCTL_REG_XFER_CMD: + return apml_rmi_reg_xfer(data, argp); default: return -ENOTTY; } diff --git a/include/uapi/misc/amd-apml.h b/include/uapi/misc/amd-apml.h index f718675d3966f..745b3338fc06f 100644 --- a/include/uapi/misc/amd-apml.h +++ b/include/uapi/misc/amd-apml.h @@ -58,6 +58,21 @@ struct apml_mcamsr_msg { __u32 pad; }; +struct apml_reg_xfer_msg { + /* + * RMI register address offset + */ + __u16 reg_addr; + /* + * Register data for read/write + */ + __u8 data_in_out; + /* + * Register read or write + */ + __u8 rflag; +}; + /* * AMD sideband interface base IOCTL */ @@ -118,4 +133,20 @@ struct apml_mcamsr_msg { */ #define SBRMI_IOCTL_MCAMSR_CMD _IOWR(SB_BASE_IOCTL_NR, 2, struct apml_mcamsr_msg) +/** + * DOC: SBRMI_IOCTL_REG_XFER_CMD + * + * @Parameters + * + * @struct apml_reg_xfer_msg + * Pointer to the &struct apml_reg_xfer_msg that will contain the protocol + * information + * + * @Description + * IOCTL command for APML messages using generic _IOWR + * The IOCTL provides userspace access to AMD sideband register xfer protocol + * - Register xfer protocol to get/set hardware register for given offset + */ +#define SBRMI_IOCTL_REG_XFER_CMD _IOWR(SB_BASE_IOCTL_NR, 3, struct apml_reg_xfer_msg) + #endif /*_AMD_APML_H_*/ -- 2.47.2