i3c: master: Add support for devices using SETAASA

Add support for devices using SETAASA, such as SPD5118 and SPD5108
attached to DDR5 memory modules that do not support ENTDAA. Follow the
guidelines proposed by the MIPI Discovery and Configuration
Specification [1] for discovering such devices.

SETAASA (Set All Addresses to Static Address) differs from standard I3C
address assignment that uses ENTDAA or SETDASA to assign dynamic
addresses. Devices using SETAASA assign their pre-defined static addresses
as their dynamic addresses during DAA, and it is not mandatory for these
devices to implement standard CCC commands like GETPID, GETDCR, or GETBCR.
For such devices, it is generally recommended to issue SETHID (specified
by JEDEC JESD300) as a prerequisite for SETAASA to stop HID bit flipping.

[1] https://www.mipi.org/mipi-disco-for-i3c-download

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Link: https://www.mipi.org/mipi-disco-for-i3c-download
Link: https://patch.msgid.link/20260728065955.809445-5-akhilrajeev@nvidia.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

1 files changed, 111 insertions, 3 deletions

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 819235440445..16260269926e 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -5,6 +5,7 @@
  * Author: Boris Brezillon <boris.brezillon@bootlin.com>
  */
 
+#include <dt-bindings/i3c/i3c.h>
 #include <linux/acpi.h>
 #include <linux/atomic.h>
 #include <linux/bitmap.h>
@@ -1164,6 +1165,51 @@ static int i3c_master_rstdaa_locked(struct i3c_master_controller *master,
 }
 
 /**
+ * i3c_master_setaasa_locked() - start a SETAASA procedure (Set All Addresses to Static Address)
+ * @master: I3C master object
+ *
+ * Send a SETAASA CCC command to set all attached I3C devices' dynamic addresses to
+ * their static address.
+ *
+ * This function must be called with the bus lock held in write mode.
+ *
+ * First, the SETHID CCC command is sent, followed by the SETAASA CCC.
+ *
+ * Return: 0 in case of success, a positive I3C error code if the error is
+ * one of the official Mx error codes, and a negative error code otherwise.
+ */
+static int i3c_master_setaasa_locked(struct i3c_master_controller *master)
+{
+	struct i3c_ccc_cmd_dest dest;
+	struct i3c_ccc_cmd cmd;
+	int ret;
+
+	/*
+	 * Send SETHID CCC command. Though it is a standard CCC command specified
+	 * in JESD300-5, we are not defining a separate macro to be explicit that
+	 * the value falls under the vendor specific range.
+	 */
+	i3c_ccc_cmd_dest_init(&dest, I3C_BROADCAST_ADDR, 0);
+	i3c_ccc_cmd_init(&cmd, false, I3C_CCC_VENDOR(0, true), &dest, 1);
+	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
+	i3c_ccc_cmd_dest_cleanup(&dest);
+	if (ret && cmd.err == I3C_ERROR_M2)
+		ret = 0;
+	if (ret)
+		return ret;
+
+	/* Send SETAASA CCC command */
+	i3c_ccc_cmd_dest_init(&dest, I3C_BROADCAST_ADDR, 0);
+	i3c_ccc_cmd_init(&cmd, false, I3C_CCC_SETAASA, &dest, 1);
+	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
+	i3c_ccc_cmd_dest_cleanup(&dest);
+	if (ret && cmd.err == I3C_ERROR_M2)
+		ret = 0;
+
+	return ret;
+}
+
+/**
  * i3c_master_entdaa_locked() - start a DAA (Dynamic Address Assignment)
  *				procedure
  * @master: master used to send frames on the bus
@@ -1939,8 +1985,10 @@ static int i3c_master_early_i3c_dev_add(struct i3c_master_controller *master,
 	int ret;
 
 	i3cdev = i3c_master_alloc_i3c_dev(master, &info);
-	if (IS_ERR(i3cdev))
-		return -ENOMEM;
+	if (IS_ERR(i3cdev)) {
+		ret = -ENOMEM;
+		goto err_reserve_addr;
+	}
 
 	i3cdev->boardinfo = boardinfo;
 
@@ -1948,6 +1996,22 @@ static int i3c_master_early_i3c_dev_add(struct i3c_master_controller *master,
 	if (ret)
 		goto err_free_dev;
 
+	/*
+	 * For devices using SETAASA instead of ENTDAA, the address is statically
+	 * assigned. Update the dynamic address to the provided static address.
+	 * Reattach the I3C device after updating the dynamic address with the same
+	 * static address. It is not mandatory for such devices to implement CCC
+	 * commands like GETPID, GETDCR etc. Hence, we can return after reattaching.
+	 */
+	if (i3cdev->boardinfo->static_addr_method & I3C_ADDR_METHOD_SETAASA) {
+		i3cdev->info.dyn_addr = i3cdev->boardinfo->static_addr;
+		ret = i3c_master_reattach_i3c_dev_locked(i3cdev, 0);
+		if (ret)
+			goto err_detach_dev;
+
+		return 0;
+	}
+
 	ret = i3c_master_setdasa_locked(master, i3cdev->info.static_addr,
 					i3cdev->boardinfo->init_dyn_addr);
 	if (ret)
@@ -1970,6 +2034,16 @@ err_detach_dev:
 	i3c_master_detach_i3c_dev(i3cdev);
 err_free_dev:
 	i3c_master_free_i3c_dev(i3cdev);
+err_reserve_addr:
+	/*
+	 * A target using SETAASA may still get the static address on the
+	 * SETAASA broadcast even if attach fails here. Keep the address
+	 * reserved so that it is not assigned to another device during DAA.
+	 */
+	if (boardinfo->static_addr_method & I3C_ADDR_METHOD_SETAASA)
+		i3c_bus_set_addr_slot_status(&master->bus,
+					     boardinfo->static_addr,
+					     I3C_ADDR_SLOT_RSVD);
 
 	return ret;
 }
@@ -2344,6 +2418,19 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
 			i3c_master_early_i3c_dev_add(master, i3cboardinfo);
 	}
 
+	/*
+	 * SETAASA is a broadcast CCC. Issue it after SETDASA so that devices
+	 * configured for SETDASA (or supporting both methods) are assigned
+	 * first, matching MIPI DISCO guidance to prefer SETDASA when both are
+	 * available. Targets that already have a dynamic address ignore the
+	 * later SETAASA broadcast.
+	 */
+	if (master->addr_method & I3C_ADDR_METHOD_SETAASA) {
+		ret = i3c_master_setaasa_locked(master);
+		if (ret)
+			goto err_rstdaa;
+	}
+
 	ret = i3c_master_do_daa(master);
 	if (ret)
 		goto err_rstdaa;
@@ -2795,7 +2882,7 @@ i3c_master_add_i3c_boardinfo(struct i3c_master_controller *master,
 	struct i3c_dev_boardinfo *boardinfo;
 	struct device *dev = &master->dev;
 	enum i3c_addr_slot_status addrstatus;
-	u32 init_dyn_addr = 0;
+	u32 init_dyn_addr = 0, static_addr_method = 0;
 
 	boardinfo = devm_kzalloc(dev, sizeof(*boardinfo), GFP_KERNEL);
 	if (!boardinfo)
@@ -2813,7 +2900,19 @@ i3c_master_add_i3c_boardinfo(struct i3c_master_controller *master,
 
 	boardinfo->static_addr = reg[0];
 
+	if (!fwnode_property_read_u32(fwnode, "mipi-i3c-static-method", &static_addr_method))
+		boardinfo->static_addr_method = static_addr_method &
+					(I3C_ADDR_METHOD_SETDASA | I3C_ADDR_METHOD_SETAASA);
+
 	if (!fwnode_property_read_u32(fwnode, "assigned-address", &init_dyn_addr)) {
+		/*
+		 * When a device advertises both SETDASA and SETAASA, an explicit
+		 * dynamic address selects SETDASA (MIPI DISCO prefers it); drop
+		 * SETAASA so it is not used for this device.
+		 */
+		if (boardinfo->static_addr_method & I3C_ADDR_METHOD_SETDASA)
+			boardinfo->static_addr_method &= ~I3C_ADDR_METHOD_SETAASA;
+
 		if (init_dyn_addr > I3C_MAX_ADDR)
 			return -EINVAL;
 
@@ -2823,6 +2922,14 @@ i3c_master_add_i3c_boardinfo(struct i3c_master_controller *master,
 			return -EINVAL;
 	}
 
+	if (boardinfo->static_addr_method & I3C_ADDR_METHOD_SETAASA) {
+		/* For SETAASA, static address is taken as the dynamic address. */
+		init_dyn_addr = boardinfo->static_addr;
+	}
+
+	/* Update the address methods required for device discovery */
+	master->addr_method |= boardinfo->static_addr_method;
+
 	boardinfo->pid = ((u64)reg[1] << 32) | reg[2];
 
 	if ((boardinfo->pid & GENMASK_ULL(63, 48)) ||
@@ -3458,6 +3565,7 @@ int i3c_master_register(struct i3c_master_controller *master,
 	master->dev.release = i3c_masterdev_release;
 	master->ops = ops;
 	master->secondary = secondary;
+	master->addr_method = I3C_ADDR_METHOD_SETDASA;
 	INIT_LIST_HEAD(&master->boardinfo.i2c);
 	INIT_LIST_HEAD(&master->boardinfo.i3c);