firmware: ti_sci: Enable abort handling of entry to LPM

The PM co-processor (device manager or DM) adds the ability to abort
entry to a low power mode by clearing the mode selection in the
latest version of its firmware (11.01.09) [1].

Enable the ti_sci driver to support the LPM abort call which clears the
low power mode selection of the DM. This fixes an issue where failed
system suspend attempts would cause subsequent suspends to fail.

After system suspend completes, regardless of if system suspend succeeds
or fails, the ->complete() hook in TI SCI will be called. In the
->complete() hook, a message will be sent to the DM to clear the current
low power mode selection. Clearing the low power mode selection
unconditionally will not cause any error in the DM.

[1] https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/pm/lpm.html

Signed-off-by: Kendall Willis <[e-mail]>
Reviewed-by: Ulf Hansson <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Nishanth Menon <[e-mail]>

drivers/firmware/ti_sci.c

···
 	return ret;
 }
 
+/**
+ * ti_sci_cmd_lpm_abort() - Abort entry to LPM by clearing selection of LPM to enter
+ * @dev:	Device pointer corresponding to the SCI entity
+ *
+ * Return: 0 if all went well, else returns appropriate error value.
+ */
+static int ti_sci_cmd_lpm_abort(struct device *dev)
+{
+	struct ti_sci_info *info = dev_get_drvdata(dev);
+	struct ti_sci_msg_hdr *req;
+	struct ti_sci_msg_hdr *resp;
+	struct ti_sci_xfer *xfer;
+	int ret = 0;
+
+	xfer = ti_sci_get_one_xfer(info, TI_SCI_MSG_LPM_ABORT,
+				   TI_SCI_FLAG_REQ_ACK_ON_PROCESSED,
+				   sizeof(*req), sizeof(*resp));
+	if (IS_ERR(xfer)) {
+		ret = PTR_ERR(xfer);
+		dev_err(dev, "Message alloc failed(%d)\n", ret);
+		return ret;
+	}
+	req = (struct ti_sci_msg_hdr *)xfer->xfer_buf;
+
+	ret = ti_sci_do_xfer(info, xfer);
+	if (ret) {
+		dev_err(dev, "Mbox send fail %d\n", ret);
+		goto fail;
+	}
+
+	resp = (struct ti_sci_msg_hdr *)xfer->xfer_buf;
+
+	if (!ti_sci_is_response_ack(resp))
+		ret = -ENODEV;
+
+fail:
+	ti_sci_put_one_xfer(&info->minfo, xfer);
+
+	return ret;
+}
+
 static int ti_sci_cmd_core_reboot(const struct ti_sci_handle *handle)
 {
 	struct ti_sci_info *info;
···
 	return 0;
 }
 
+static void __maybe_unused ti_sci_pm_complete(struct device *dev)
+{
+	struct ti_sci_info *info = dev_get_drvdata(dev);
+
+	if (info->fw_caps & MSG_FLAG_CAPS_LPM_ABORT) {
+		if (ti_sci_cmd_lpm_abort(dev))
+			dev_err(dev, "LPM clear selection failed.\n");
+	}
+}
+
 static const struct dev_pm_ops ti_sci_pm_ops = {
 #ifdef CONFIG_PM_SLEEP
 	.suspend = ti_sci_suspend,
 	.suspend_noirq = ti_sci_suspend_noirq,
 	.resume_noirq = ti_sci_resume_noirq,
+	.complete = ti_sci_pm_complete,
 #endif
 };
 
···
 	}
 
 	ti_sci_msg_cmd_query_fw_caps(&info->handle, &info->fw_caps);
-	dev_dbg(dev, "Detected firmware capabilities: %s%s%s\n",
+	dev_dbg(dev, "Detected firmware capabilities: %s%s%s%s\n",
 		info->fw_caps & MSG_FLAG_CAPS_GENERIC ? "Generic" : "",
 		info->fw_caps & MSG_FLAG_CAPS_LPM_PARTIAL_IO ? " Partial-IO" : "",
-		info->fw_caps & MSG_FLAG_CAPS_LPM_DM_MANAGED ? " DM-Managed" : ""
+		info->fw_caps & MSG_FLAG_CAPS_LPM_DM_MANAGED ? " DM-Managed" : "",
+		info->fw_caps & MSG_FLAG_CAPS_LPM_ABORT ? " LPM-Abort" : ""
 	);
 
 	ti_sci_setup_ops(info);

drivers/firmware/ti_sci.h

···
 #define TI_SCI_MSG_SET_IO_ISOLATION	0x0307
 #define TI_SCI_MSG_LPM_SET_DEVICE_CONSTRAINT	0x0309
 #define TI_SCI_MSG_LPM_SET_LATENCY_CONSTRAINT	0x030A
+#define TI_SCI_MSG_LPM_ABORT	0x0311
 
 /* Resource Management Requests */
 #define TI_SCI_MSG_GET_RESOURCE_RANGE	0x1500
···
  *		MSG_FLAG_CAPS_GENERIC: Generic capability (LPM not supported)
  *		MSG_FLAG_CAPS_LPM_PARTIAL_IO: Partial IO in LPM
  *		MSG_FLAG_CAPS_LPM_DM_MANAGED: LPM can be managed by DM
+ *		MSG_FLAG_CAPS_LPM_ABORT: Abort entry to LPM
  *
  * Response to a generic message with message type TI_SCI_MSG_QUERY_FW_CAPS
  * providing currently available SOC/firmware capabilities. SoC that don't
···
 #define MSG_FLAG_CAPS_GENERIC		TI_SCI_MSG_FLAG(0)
 #define MSG_FLAG_CAPS_LPM_PARTIAL_IO	TI_SCI_MSG_FLAG(4)
 #define MSG_FLAG_CAPS_LPM_DM_MANAGED	TI_SCI_MSG_FLAG(5)
+#define MSG_FLAG_CAPS_LPM_ABORT		TI_SCI_MSG_FLAG(9)
 #define MSG_MASK_CAPS_LPM		GENMASK_ULL(4, 1)
 	u64 fw_caps;
 } __packed;