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Subject[PATCH 08/10] platform/x86: ISST: Add Intel Speed Select PUNIT MSR interface
Date
While using new non arhitectural features using PUNIT Mailbox and MMIO
read/write interface, still there is need to operate using MSRs to
control PUNIT. User space could have used user user-space MSR interface for
this, but when user space MSR access is disabled, then it can't. Here only
limited number of MSRs are allowed using this new interface.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
.../intel_speed_select_if/isst_if_common.c | 59 +++++++++++++++++++
include/uapi/linux/isst_if.h | 32 ++++++++++
2 files changed, 91 insertions(+)

diff --git a/drivers/platform/x86/intel_speed_select_if/isst_if_common.c b/drivers/platform/x86/intel_speed_select_if/isst_if_common.c
index 391fc3f12161..de2fb5292f1c 100644
--- a/drivers/platform/x86/intel_speed_select_if/isst_if_common.c
+++ b/drivers/platform/x86/intel_speed_select_if/isst_if_common.c
@@ -25,6 +25,11 @@

static struct isst_if_cmd_cb punit_callbacks[ISST_IF_DEV_MAX];

+static int punit_msr_white_list[] = {
+ MSR_TURBO_RATIO_LIMIT,
+ MSR_CONFIG_TDP_CONTROL,
+};
+
struct isst_valid_cmd_ranges {
u16 cmd;
u16 sub_cmd_beg;
@@ -229,6 +234,54 @@ static long isst_if_proc_phyid_req(u8 *cmd_ptr, int *write_only, int resume)
return 0;
}

+static bool match_punit_msr_white_list(int msr)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(punit_msr_white_list); ++i) {
+ if (punit_msr_white_list[i] == msr)
+ return true;
+ }
+
+ return false;
+}
+
+static long isst_if_msr_cmd_req(u8 *cmd_ptr, int *write_only, int resume)
+{
+ struct isst_if_msr_cmd *msr_cmd;
+ int ret;
+
+ msr_cmd = (struct isst_if_msr_cmd *)cmd_ptr;
+
+ if (!match_punit_msr_white_list(msr_cmd->msr))
+ return -EINVAL;
+
+ if (msr_cmd->logical_cpu >= nr_cpu_ids)
+ return -EINVAL;
+
+ if (msr_cmd->read_write) {
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ ret = wrmsrl_safe_on_cpu(msr_cmd->logical_cpu,
+ msr_cmd->msr,
+ msr_cmd->data);
+ *write_only = 1;
+ } else {
+ u64 data;
+
+ ret = rdmsrl_safe_on_cpu(msr_cmd->logical_cpu,
+ msr_cmd->msr, &data);
+ if (!ret) {
+ msr_cmd->data = data;
+ *write_only = 0;
+ }
+ }
+
+
+ return ret;
+}
+
static long isst_if_exec_multi_cmd(void __user *argp, struct isst_if_cmd_cb *cb)
{
unsigned char __user *ptr;
@@ -309,6 +362,12 @@ static long isst_if_def_ioctl(struct file *file, unsigned int cmd,
if (cb->registered)
ret = isst_if_exec_multi_cmd(argp, cb);
break;
+ case ISST_IF_MSR_COMMAND:
+ cmd_cb.cmd_size = sizeof(struct isst_if_msr_cmd);
+ cmd_cb.offset = offsetof(struct isst_if_msr_cmds, msr_cmd);
+ cmd_cb.cmd_callback = isst_if_msr_cmd_req;
+ ret = isst_if_exec_multi_cmd(argp, &cmd_cb);
+ break;
default:
break;
}
diff --git a/include/uapi/linux/isst_if.h b/include/uapi/linux/isst_if.h
index e4b1c2ec3279..d10b832c58c5 100644
--- a/include/uapi/linux/isst_if.h
+++ b/include/uapi/linux/isst_if.h
@@ -132,9 +132,41 @@ struct isst_if_mbox_cmds {
struct isst_if_mbox_cmd mbox_cmd[1];
};

+/**
+ * struct isst_if_msr_cmd - Structure to define msr command
+ * @read_write: Value 0: Read, 1: Write
+ * @logical_cpu: Logical CPU number
+ * @msr: MSR number
+ * @data: For write operation, data to write, for read
+ * place holder
+ *
+ * Structure to specify MSR command related to PUNIT.
+ */
+struct isst_if_msr_cmd {
+ __u32 read_write; /* Read:0, Write:1 */
+ __u32 logical_cpu;
+ __u64 msr;
+ __u64 data;
+};
+
+/**
+ * struct isst_if_msr_cmds - structure for msr commands
+ * @cmd_count: Number of mailbox commands in msr_cmd[]
+ * @msr_cmd[]: Holds one or more msr commands
+ *
+ * This structure used with ioctl ISST_IF_MSR_COMMAND to send
+ * one or more MSR commands. IOCTL return value indicates number of
+ * commands sent or error number if no commands have been sent.
+ */
+struct isst_if_msr_cmds {
+ __u32 cmd_count;
+ struct isst_if_msr_cmd msr_cmd[1];
+};
+
#define ISST_IF_MAGIC 0xFE
#define ISST_IF_GET_PLATFORM_INFO _IOR(ISST_IF_MAGIC, 0, struct isst_if_platform_info *)
#define ISST_IF_GET_PHY_ID _IOWR(ISST_IF_MAGIC, 1, struct isst_if_cpu_map *)
#define ISST_IF_IO_CMD _IOW(ISST_IF_MAGIC, 2, struct isst_if_io_regs *)
#define ISST_IF_MBOX_COMMAND _IOWR(ISST_IF_MAGIC, 3, struct isst_if_mbox_cmds *)
+#define ISST_IF_MSR_COMMAND _IOWR(ISST_IF_MAGIC, 4, struct isst_if_msr_cmds *)
#endif
--
2.17.2
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