Commit e46ceea3 authored Jan 04, 2023 by Chen-Yu Tsai Committed by Mathieu Poirier Jan 04, 2023

remoteproc/mtk_scp: Move clk ops outside send_lock



Clocks are properly reference counted and do not need to be inside the
lock range.

Right now this triggers a false-positive lockdep warning on MT8192 based
Chromebooks, through a combination of mtk-scp that has a cros-ec-rpmsg
sub-device, the (actual) cros-ec I2C adapter registration, I2C client
(not on cros-ec) probe doing i2c transfers and enabling clocks.

This is a false positive because the cros-ec-rpmsg under mtk-scp does
not have an I2C adapter, and also each I2C adapter and cros-ec instance
have their own mutex.

Move the clk operations outside of the send_lock range.

Fixes: 63c13d61 ("remoteproc/mediatek: add SCP support for mt8183")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230104083110.736377-1-wenst@chromium.org


[Fixed "Fixes:" tag line]
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

parent cf5865e7

drivers/remoteproc/mtk_scp_ipi.c

+5 −6

Original line number	Diff line number	Diff line
		@@ -164,21 +164,21 @@ int scp_ipi_send(struct mtk_scp scp, u32 id, void buf, unsigned int len,
		WARN_ON(len > sizeof(send_obj->share_buf)) \|\| WARN_ON(!buf))
		return -EINVAL;

		mutex_lock(&scp->send_lock);

		ret = clk_prepare_enable(scp->clk);
		if (ret) {
		dev_err(scp->dev, "failed to enable clock\n");
		goto unlock_mutex;
		return ret;
		}

		mutex_lock(&scp->send_lock);

		/* Wait until SCP receives the last command */
		timeout = jiffies + msecs_to_jiffies(2000);
		do {
		if (time_after(jiffies, timeout)) {
		dev_err(scp->dev, "%s: IPI timeout!\n", __func__);
		ret = -ETIMEDOUT;
		goto clock_disable;
		goto unlock_mutex;
		}
		} while (readl(scp->reg_base + scp->data->host_to_scp_reg));

		@@ -205,10 +205,9 @@ int scp_ipi_send(struct mtk_scp scp, u32 id, void buf, unsigned int len,
		ret = 0;
		}

		clock_disable:
		clk_disable_unprepare(scp->clk);
		unlock_mutex:
		mutex_unlock(&scp->send_lock);
		clk_disable_unprepare(scp->clk);

		return ret;
		}