soc: qcom: rpmh-rsc: Enhance check for VRM in-flight request

Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte aligned
addresses associated with it. These control voltage, enable state, mode,
and in legacy targets, voltage headroom. The current in-flight request
checking logic looks for exact address matches. Requests for different
addresses of the same RPMh resource as thus not detected as in-flight.

Add new cmd-db API cmd_db_match_resource_addr() to enhance the in-flight
request check for VRM requests by ignoring the address offset.

This ensures that only one request is allowed to be in-flight for a given
VRM resource. This is needed to avoid scenarios where request commands are
carried out by RPMh hardware out-of-order leading to LDO regulator
over-current protection triggering.

Fixes: 658628e ("drivers: qcom: rpmh-rsc: add RPMH controller for QCOM SoCs")
Cc: [email protected]
Reviewed-by: Konrad Dybcio <[email protected]>
Tested-by: Elliot Berman <[email protected]> # sm8650-qrd
Signed-off-by: Maulik Shah <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Andersson <[email protected]>

Author: maulik-k-shah

drivers/soc/qcom/cmd-db.c

@@ -1,6 +1,10 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-/* Copyright (c) 2016-2018, 2020, The Linux Foundation. All rights reserved. */
+/*
+ * Copyright (c) 2016-2018, 2020, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2024, Qualcomm Innovation Center, Inc. All rights reserved.
+ */
 
+#include <linux/bitfield.h>
 #include <linux/debugfs.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -17,6 +21,8 @@
 #define MAX_SLV_ID		8
 #define SLAVE_ID_MASK		0x7
 #define SLAVE_ID_SHIFT		16
+#define SLAVE_ID(addr)		FIELD_GET(GENMASK(19, 16), addr)
+#define VRM_ADDR(addr)		FIELD_GET(GENMASK(19, 4), addr)
 
 /**
  * struct entry_header: header for each entry in cmddb
@@ -220,6 +226,30 @@ const void *cmd_db_read_aux_data(const char *id, size_t *len)
 }
 EXPORT_SYMBOL_GPL(cmd_db_read_aux_data);
 
+/**
+ * cmd_db_match_resource_addr() - Compare if both Resource addresses are same
+ *
+ * @addr1: Resource address to compare
+ * @addr2: Resource address to compare
+ *
+ * Return: true if two addresses refer to the same resource, false otherwise
+ */
+bool cmd_db_match_resource_addr(u32 addr1, u32 addr2)
+{
+	/*
+	 * Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte
+	 * aligned addresses associated with it. Ignore the offset to check
+	 * for VRM requests.
+	 */
+	if (addr1 == addr2)
+		return true;
+	else if (SLAVE_ID(addr1) == CMD_DB_HW_VRM && VRM_ADDR(addr1) == VRM_ADDR(addr2))
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(cmd_db_match_resource_addr);
+
 /**
  * cmd_db_read_slave_id - Get the slave ID for a given resource address
  *

drivers/soc/qcom/rpmh-rsc.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2023-2024, Qualcomm Innovation Center, Inc. All rights reserved.
  */
 
 #define pr_fmt(fmt) "%s " fmt, KBUILD_MODNAME
@@ -557,7 +558,7 @@ static int check_for_req_inflight(struct rsc_drv *drv, struct tcs_group *tcs,
 		for_each_set_bit(j, &curr_enabled, MAX_CMDS_PER_TCS) {
 			addr = read_tcs_cmd(drv, drv->regs[RSC_DRV_CMD_ADDR], i, j);
 			for (k = 0; k < msg->num_cmds; k++) {
-				if (addr == msg->cmds[k].addr)
+				if (cmd_db_match_resource_addr(msg->cmds[k].addr, addr))
 					return -EBUSY;
 			}
 		}

include/soc/qcom/cmd-db.h

@@ -1,5 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-/* Copyright (c) 2016-2018, The Linux Foundation. All rights reserved. */
+/*
+ * Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2024, Qualcomm Innovation Center, Inc. All rights reserved.
+ */
 
 #ifndef __QCOM_COMMAND_DB_H__
 #define __QCOM_COMMAND_DB_H__
@@ -21,6 +24,8 @@ u32 cmd_db_read_addr(const char *resource_id);
 
 const void *cmd_db_read_aux_data(const char *resource_id, size_t *len);
 
+bool cmd_db_match_resource_addr(u32 addr1, u32 addr2);
+
 enum cmd_db_hw_type cmd_db_read_slave_id(const char *resource_id);
 
 int cmd_db_ready(void);
@@ -31,6 +36,9 @@ static inline u32 cmd_db_read_addr(const char *resource_id)
 static inline const void *cmd_db_read_aux_data(const char *resource_id, size_t *len)
 { return ERR_PTR(-ENODEV); }
 
+static inline bool cmd_db_match_resource_addr(u32 addr1, u32 addr2)
+{ return false; }
+
 static inline enum cmd_db_hw_type cmd_db_read_slave_id(const char *resource_id)
 { return -ENODEV; }