linux-kernel - [PATCH v2] soc: qcom: rpmh-rsc: Enhance check for VREG in-flight request

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Message-ID: <20240119-rpmh-rsc-fixes-v2-1-e42c0a9e36f0@quicinc.com>
Date: Fri, 19 Jan 2024 13:56:54 +0530
From: Maulik Shah <quic_mkshah@...cinc.com>
To: Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio
	<konrad.dybcio@...aro.org>
CC: <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <quic_eberman@...cinc.com>, <quic_collinsd@...cinc.com>,
        <quic_lsrao@...cinc.com>, Maulik Shah <quic_mkshah@...cinc.com>
Subject: [PATCH v2] soc: qcom: rpmh-rsc: Enhance check for VREG in-flight
 request

Each RPMh VREG 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.

Enhance the in-flight request check for VREG requests by ignoring the
address offset. This ensures that only one request is allowed to be
in-flight for a given VREG 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.

Signed-off-by: Maulik Shah <quic_mkshah@...cinc.com>
Signed-off-by: Elliot Berman <quic_eberman@...cinc.com>
---
Changes in v2:
- Use GENMASK() and FIELD_GET()
- Link to v1: https://lore.kernel.org/r/20240117-rpmh-rsc-fixes-v1-1-71ee4f8f72a4@quicinc.com
---
 drivers/soc/qcom/rpmh-rsc.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index a021dc71807b..e480cde783fe 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -1,11 +1,13 @@
 // 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
 
 #include <linux/atomic.h>
+#include <linux/bitfield.h>
 #include <linux/cpu_pm.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
@@ -91,6 +93,15 @@ enum {
 #define CMD_STATUS_ISSUED		BIT(8)
 #define CMD_STATUS_COMPL		BIT(16)
 
+#define ACCL_TYPE(addr)			FIELD_GET(GENMASK(19, 16), addr)
+#define VREG_ADDR(addr)			FIELD_GET(GENMASK(19, 4), addr)
+
+enum {
+	HW_ACCL_CLK = 0x3,
+	HW_ACCL_VREG,
+	HW_ACCL_BUS,
+};
+
 /*
  * Here's a high level overview of how all the registers in RPMH work
  * together:
@@ -557,7 +568,15 @@ 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)
+				/*
+				 * Each RPMh VREG accelerator resource has 3 or 4 contiguous 4-byte
+				 * aligned addresses associated with it. Ignore the offset to check
+				 * for in-flight VREG requests.
+				 */
+				if (ACCL_TYPE(msg->cmds[k].addr) == HW_ACCL_VREG &&
+				    VREG_ADDR(msg->cmds[k].addr) == VREG_ADDR(addr))
+					return -EBUSY;
+				else if (addr == msg->cmds[k].addr)
 					return -EBUSY;
 			}
 		}

---
base-commit: 943b9f0ab2cfbaea148dd6ac279957eb08b96904
change-id: 20240117-rpmh-rsc-fixes-6c43c7051828

Best regards,
-- 
Maulik Shah <quic_mkshah@...cinc.com>