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: 658628e7ef78 ("drivers: qcom: rpmh-rsc: add RPMH controller for QCOM SoCs")
Cc: stable@vger.kernel.org
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Tested-by: Elliot Berman <quic_eberman@quicinc.com> # sm8650-qrd
Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Link: https://lore.kernel.org/r/20240215-rpmh-rsc-fixes-v4-1-9cbddfcba05b@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

2 files changed, 33 insertions, 2 deletions

diff --git a/drivers/soc/qcom/cmd-db.c b/drivers/soc/qcom/cmd-db.c
index c344107bc36c..b4e613c34a5c 100644
--- a/drivers/soc/qcom/cmd-db.c
+++ b/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
@@ -221,6 +227,30 @@ 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
  *
  * @id: Resource id to query the DB for version
diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index c4c7aad957e6..561d8037b50a 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/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;
 			}
 		}