nvme: Add APST payload overriding

The apst_data tunable allows APST configuration to be adjusted during controller initialization. It accepts an array of encoded integers, each defining specific transition parameters. Signed-off-by: Alexey Sukhoguzov <[email protected]>
freebsd · Oct 31, 2024 · b574aae · b574aae
1 parent ae098ac
commit b574aae
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Showing 2 changed files with 26 additions and 7 deletions.
diff --git a/share/man/man4/nvme.4 b/share/man/man4/nvme.4
@@ -136,6 +136,18 @@ hw.nvme.apst_enable=1
 .Ed
 .Pp
 The default vendor-provided settings, if any, will be applied.
+To override this, set the following tunable:
+.Bd -literal -offset indent
+hw.nvme.apst_data
+.Ed
+.Pp
+The string must contain up to 32 encoded integers, e.g. "0x6418 0
+0 0x3e820".
+Each value corresponds to a specific available power state starting
+from the lowest, and defines the target state (bits 3..7) to
+transition to, as well as the idle time in milliseconds (bits 8..31)
+to wait before that transition.
+Bits 0..2 must be zero.
 .Pp
 The
 .Xr nvd 4

diff --git a/sys/dev/nvme/nvme_ctrlr.c b/sys/dev/nvme/nvme_ctrlr.c
@@ -893,6 +893,7 @@ nvme_ctrlr_configure_apst(struct nvme_controller *ctrlr)
 	struct nvme_completion_poll_status status;
 	uint64_t *data;
 	int data_size = 32 * sizeof(*data);
+	int i, read_size;
 	bool enable;
 
 	if (TUNABLE_BOOL_FETCH("hw.nvme.apst_enable", &enable) == 0 ||
@@ -902,14 +903,20 @@ nvme_ctrlr_configure_apst(struct nvme_controller *ctrlr)
 	if ((data = malloc(data_size, M_NVME, M_WAITOK | M_ZERO)) == NULL)
 		goto fail;
 
-	status.done = 0;
-	nvme_ctrlr_cmd_get_feature(ctrlr,
-	    NVME_FEAT_AUTONOMOUS_POWER_STATE_TRANSITION, 0,
-	    data, data_size, nvme_completion_poll_cb, &status);
+	if (getenv_array("hw.nvme.apst_data", data, data_size,
+	    &read_size, sizeof(*data), GETENV_UNSIGNED) != 0) {
+		for (i = 0; i < read_size / sizeof(*data); ++i)
+			data[i] = htole64(data[i]);
+	} else {
+		status.done = 0;
+		nvme_ctrlr_cmd_get_feature(ctrlr,
+		    NVME_FEAT_AUTONOMOUS_POWER_STATE_TRANSITION, 0,
+		    data, data_size, nvme_completion_poll_cb, &status);
 
-	nvme_completion_poll(&status);
-	if (nvme_completion_is_error(&status.cpl))
-		goto fail;
+		nvme_completion_poll(&status);
+		if (nvme_completion_is_error(&status.cpl))
+			goto fail;
+	}
 
 	status.done = 0;
 	nvme_ctrlr_cmd_set_feature(ctrlr,