6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sanman Pradhan <psanman@juniper.net>
commit 75d42d990335322852ed5f7ce324b701c0949d79 upstream.
hisi_ptt_wait_dma_reset_done() discards the return value of
readl_poll_timeout_atomic(). If the DMA engine does not complete its
reset within the timeout, hisi_ptt_trace_start() proceeds to start
tracing regardless.
Return a bool from hisi_ptt_wait_dma_reset_done(), consistent with the
other wait helpers in this driver. On timeout, log an error, de-assert
the reset bit, and return -ETIMEDOUT. Move ctrl->started to the
successful path so a failed start does not leave the trace marked as
active.
Fixes: ff0de066b463 ("hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe Tune and Trace device")
Cc: <redacted>
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Reviewed-by: Sizhe Liu <liusizhe5@huawei.com>
Reviewed-by: Yicong Yang <redacted>
Tested-by: Sizhe Liu <liusizhe5@huawei.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260414172451.14331-2-sanman.pradhan@hpe.com (local)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hwtracing/ptt/hisi_ptt.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
--- a/drivers/hwtracing/ptt/hisi_ptt.c
+++ b/drivers/hwtracing/ptt/hisi_ptt.c
@@ -171,13 +171,13 @@ static bool hisi_ptt_wait_trace_hw_idle(
HISI_PTT_WAIT_TRACE_TIMEOUT_US);
}
-static void hisi_ptt_wait_dma_reset_done(struct hisi_ptt *hisi_ptt)
+static bool hisi_ptt_wait_dma_reset_done(struct hisi_ptt *hisi_ptt)
{
u32 val;
- readl_poll_timeout_atomic(hisi_ptt->iobase + HISI_PTT_TRACE_WR_STS,
- val, !val, HISI_PTT_RESET_POLL_INTERVAL_US,
- HISI_PTT_RESET_TIMEOUT_US);
+ return !readl_poll_timeout_atomic(hisi_ptt->iobase + HISI_PTT_TRACE_WR_STS,
+ val, !val, HISI_PTT_RESET_POLL_INTERVAL_US,
+ HISI_PTT_RESET_TIMEOUT_US);
}
static void hisi_ptt_trace_end(struct hisi_ptt *hisi_ptt)@@ -198,14 +198,18 @@ static int hisi_ptt_trace_start(struct h
return -EBUSY;
}
- ctrl->started = true;
-
/* Reset the DMA before start tracing */
val = readl(hisi_ptt->iobase + HISI_PTT_TRACE_CTRL);
val |= HISI_PTT_TRACE_CTRL_RST;
writel(val, hisi_ptt->iobase + HISI_PTT_TRACE_CTRL);
- hisi_ptt_wait_dma_reset_done(hisi_ptt);
+ if (!hisi_ptt_wait_dma_reset_done(hisi_ptt)) {
+ pci_err(hisi_ptt->pdev, "timed out waiting for DMA reset\n");
+ val = readl(hisi_ptt->iobase + HISI_PTT_TRACE_CTRL);
+ val &= ~HISI_PTT_TRACE_CTRL_RST;
+ writel(val, hisi_ptt->iobase + HISI_PTT_TRACE_CTRL);
+ return -ETIMEDOUT;
+ }
val = readl(hisi_ptt->iobase + HISI_PTT_TRACE_CTRL);
val &= ~HISI_PTT_TRACE_CTRL_RST;@@ -230,6 +234,8 @@ static int hisi_ptt_trace_start(struct h
if (!hisi_ptt->trace_ctrl.is_port)
val |= HISI_PTT_TRACE_CTRL_FILTER_MODE;
+ ctrl->started = true;
+
/* Start the Trace */
val |= HISI_PTT_TRACE_CTRL_EN;
writel(val, hisi_ptt->iobase + HISI_PTT_TRACE_CTRL);