firmware: ti_sci: Add support for querying the firmware caps

Add support for the TISCI_MSG_QUERY_FW_CAPS message, used to retrieve
the firmware capabilities of the currently running system firmware. The
message belongs to the TISCI general core message API [1] and is
available in SysFW version 08.04.03 and above. Currently, the message is
supported on devices with split architecture of the system firmware (DM
+ TIFS) like AM62x. Old revisions or not yet supported platforms will
NACK this request.

We're using this message locally in ti_sci.c to get the low power
features of the FW/SoC. As there's no other kernel consumers yet, this
is not added to struct ti_sci_core_ops.

Sysfw version >= 10.00.04 support LPM_DM_MANAGED capability [2], where
Device Mgr firmware now manages which low power mode is chosen. Going
forward, this is the default configuration supported for TI AM62 family
of devices. The state chosen by the DM can be influenced by sending
constraints using the new LPM constraint APIs.

[1] https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/general/core.html
[2] https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/general/core.html#tisci-msg-query-fw-caps

Signed-off-by: Georgi Vlaev <g-vlaev@ti.com>
[vibhore@ti.com: Support for LPM_DM_MANAGED mode]
Signed-off-by: Vibhore Vardhan <vibhore@ti.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Tested-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Tested-by: Roger Quadros <rogerq@kernel.org>
Acked-by: Dhruva Gole <d-gole@ti.com>
Link: https://lore.kernel.org/r/20241007-tisci-syssuspendresume-v13-2-ed54cd659a49@baylibre.com
Signed-off-by: Nishanth Menon <nm@ti.com>

1 files changed, 72 insertions, 1 deletions

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 160968301b1f..d53192607709 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -2,7 +2,7 @@
 /*
  * Texas Instruments System Control Interface Protocol Driver
  *
- * Copyright (C) 2015-2022 Texas Instruments Incorporated - https://www.ti.com/
+ * Copyright (C) 2015-2024 Texas Instruments Incorporated - https://www.ti.com/
  *	Nishanth Menon
  */
 
@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/soc/ti/ti-msgmgr.h>
 #include <linux/soc/ti/ti_sci_protocol.h>
+#include <linux/sys_soc.h>
 #include <linux/reboot.h>
 
 #include "ti_sci.h"
@@ -98,6 +99,7 @@ struct ti_sci_desc {
  * @minfo:	Message info
  * @node:	list head
  * @host_id:	Host ID
+ * @fw_caps:	FW/SoC low power capabilities
  * @users:	Number of users of this instance
  */
 struct ti_sci_info {
@@ -114,6 +116,7 @@ struct ti_sci_info {
 	struct ti_sci_xfers_info minfo;
 	struct list_head node;
 	u8 host_id;
+	u64 fw_caps;
 	/* protected by ti_sci_list_mutex */
 	int users;
 };
@@ -1651,6 +1654,67 @@ fail:
 	return ret;
 }
 
+/**
+ * ti_sci_msg_cmd_query_fw_caps() - Get the FW/SoC capabilities
+ * @handle:		Pointer to TI SCI handle
+ * @fw_caps:		Each bit in fw_caps indicating one FW/SOC capability
+ *
+ * Check if the firmware supports any optional low power modes.
+ * Old revisions of TIFS (< 08.04) will NACK the request which results in
+ * -ENODEV being returned.
+ *
+ * Return: 0 if all went well, else returns appropriate error value.
+ */
+static int ti_sci_msg_cmd_query_fw_caps(const struct ti_sci_handle *handle,
+					u64 *fw_caps)
+{
+	struct ti_sci_info *info;
+	struct ti_sci_xfer *xfer;
+	struct ti_sci_msg_resp_query_fw_caps *resp;
+	struct device *dev;
+	int ret = 0;
+
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	if (!handle)
+		return -EINVAL;
+
+	info = handle_to_ti_sci_info(handle);
+	dev = info->dev;
+
+	xfer = ti_sci_get_one_xfer(info, TI_SCI_MSG_QUERY_FW_CAPS,
+				   TI_SCI_FLAG_REQ_ACK_ON_PROCESSED,
+				   sizeof(struct ti_sci_msg_hdr),
+				   sizeof(*resp));
+	if (IS_ERR(xfer)) {
+		ret = PTR_ERR(xfer);
+		dev_err(dev, "Message alloc failed(%d)\n", ret);
+		return ret;
+	}
+
+	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_resp_query_fw_caps *)xfer->xfer_buf;
+
+	if (!ti_sci_is_response_ack(resp)) {
+		dev_err(dev, "Failed to get capabilities\n");
+		ret = -ENODEV;
+		goto fail;
+	}
+
+	if (fw_caps)
+		*fw_caps = resp->fw_caps;
+
+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;
@@ -3390,6 +3454,13 @@ static int ti_sci_probe(struct platform_device *pdev)
 		goto out;
 	}
 
+	ti_sci_msg_cmd_query_fw_caps(&info->handle, &info->fw_caps);
+	dev_dbg(dev, "Detected firmware capabilities: %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" : ""
+	);
+
 	ti_sci_setup_ops(info);
 
 	ret = devm_register_restart_handler(dev, tisci_reboot_handler, info);