linux-kernel - [PATCH] coresight-tmc-etr: Fix busy error when enable multiple sources

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Message-ID: <20231012110754.32635-1-quic_jinlmao@quicinc.com>
Date:   Thu, 12 Oct 2023 19:07:54 +0800
From:   Mao Jinlong <quic_jinlmao@...cinc.com>
To:     Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        James Clark <james.clark@....com>,
        Leo Yan <leo.yan@...aro.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>
CC:     Mao Jinlong <quic_jinlmao@...cinc.com>,
        <coresight@...ts.linaro.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        Tingwei Zhang <quic_tingweiz@...cinc.com>,
        Yuanfang Zhang <quic_yuanfang@...cinc.com>,
        Tao Zhang <quic_taozha@...cinc.com>
Subject: [PATCH] coresight-tmc-etr: Fix busy error when enable multiple sources

In enable sink sysfs function, when etr is enabled, it doesn't need
to call enable hw function again.

[   91.057233] ------------[ cut here ]------------
[   91.061983] WARNING: CPU: 6 PID: 145 at drivers/hwtracing/coresight/coresight-tmc-etr.c:1038 tmc_etr_enable_hw+0xc4/0xd0
[   91.073153] Modules linked in:
[   91.076302] CPU: 6 PID: 145 Comm: sh Tainted: G S      W          6.5.0-rc3-g66d5eaa9e5a7 #111
[   91.085149] Hardware name: Qualcomm Technologies, Inc. SM8450 QRD (DT)
[   91.091847] pstate: 634000c5 (nZCv daIF +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
[   91.099000] pc : tmc_etr_enable_hw+0xc4/0xd0
[   91.103389] lr : tmc_enable_etr_sink+0x13c/0x294
[   91.108130] sp : ffff8000815cbb30
[   91.111537] x29: ffff8000815cbb30 x28: ffff68ce4352a800 x27: 0000000000000000
[   91.118868] x26: ffff68ce414cc040 x25: ffff68ce414a82e0 x24: 0000000000000000
[   91.126199] x23: ffff68ce423a1ee0 x22: ffff68ce423a1e80 x21: ffff68ce4352a800
[   91.133527] x20: 0000000000000001 x19: ffff68ce414aa500 x18: fffffda31cf9c008
[   91.140857] x17: 0000000000000040 x16: 0000000000000001 x15: fffffc0000000000
[   91.148188] x14: 00000000f0000080 x13: 0000000000000000 x12: ffff9739c0000000
[   91.155516] x11: ffffbe9cdf71e400 x10: 0000000000001000 x9 : ffff68d0b29e3b28
[   91.162845] x8 : fffffda31cf983c8 x7 : fffffda31cf98388 x6 : 00000000ffffffd0
[   91.170174] x5 : ffff68ce435d8ec0 x4 : ffff68d0b29e2610 x3 : ffff68ce435d8ec0
[   91.177502] x2 : ffff68ce414aa500 x1 : ffff68ce414aa500 x0 : ffff68ce423a1e80
[   91.184833] Call trace:
[   91.187349]  tmc_etr_enable_hw+0xc4/0xd0
[   91.191388]  tmc_enable_etr_sink+0x13c/0x294
[   91.195777]  coresight_enable_path+0x21c/0x24c
[   91.200347]  coresight_enable+0x9c/0x204
[   91.204379]  enable_source_store+0x58/0xa0
[   91.208595]  dev_attr_store+0x18/0x2c
[   91.212361]  sysfs_kf_write+0x40/0x54
[   91.216126]  kernfs_fop_write_iter+0x164/0x1dc
[   91.220692]  vfs_write+0x3a8/0x460
[   91.224191]  ksys_write+0x6c/0x100
[   91.227690]  __arm64_sys_write+0x1c/0x28
[   91.231728]  invoke_syscall+0x44/0x100
[   91.235586]  el0_svc_common.constprop.1+0x6c/0xe4
[   91.240418]  do_el0_svc+0x38/0x94
[   91.243833]  el0_svc+0x28/0x74
[   91.246981]  el0t_64_sync_handler+0xa0/0xc4
[   91.251282]  el0t_64_sync+0x174/0x178
[   91.255045] ---[ end trace 0000000000000000 ]---
sh: write error: Device or resource busy

Signed-off-by: Mao Jinlong <quic_jinlmao@...cinc.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 66dc5f97a009..e1c7bae9f6ee 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1204,7 +1204,7 @@ static struct etr_buf *tmc_etr_get_sysfs_buffer(struct coresight_device *csdev)
 
 static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev)
 {
-	int ret;
+	int ret = 0;
 	unsigned long flags;
 	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 	struct etr_buf *sysfs_buf = tmc_etr_get_sysfs_buffer(csdev);
@@ -1213,12 +1213,16 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev)
 		return PTR_ERR(sysfs_buf);
 
 	spin_lock_irqsave(&drvdata->spinlock, flags);
+	if (drvdata->mode == CS_MODE_SYSFS)
+		goto out;
+
 	ret = tmc_etr_enable_hw(drvdata, sysfs_buf);
 	if (!ret) {
 		drvdata->mode = CS_MODE_SYSFS;
 		atomic_inc(&csdev->refcnt);
 	}
 
+out:
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	if (!ret)
-- 
2.17.1