Clock matrix driver can be probed before the rootfs containing
firmware/initialization .bin is available. The current driver
throws a warning and proceeds to execute probe even when firmware
is not ready. Instead, defer probe and wait for the .bin file to
be available.

Signed-off-by: Sarath Babu Naidu Gaddam <sarath.babu.naidu.gaddam@amd.com>
---
Changes in V2:
1) Added mutex_unlock(idtcm->lock); before returning EPROBE_DEFER.
2) Moved failure log after defer probe.
---
 drivers/ptp/ptp_clockmatrix.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/ptp/ptp_clockmatrix.c b/drivers/ptp/ptp_clockmatrix.c
index c9d451bf89e2..b3cb136257e3 100644
--- a/drivers/ptp/ptp_clockmatrix.c
+++ b/drivers/ptp/ptp_clockmatrix.c
@@ -2424,8 +2424,13 @@ static int idtcm_probe(struct platform_device *pdev)
 
 	err = idtcm_load_firmware(idtcm, &pdev->dev);
 
-	if (err)
+	if (err) {
+		if (err == -ENOENT) {
+			mutex_unlock(idtcm->lock);
+			return -EPROBE_DEFER;
+		}
 		dev_warn(idtcm->dev, "loading firmware failed with %d", err);
+	}
 
 	wait_for_chip_ready(idtcm);
 
-- 
2.25.1

On Wed, 14 Jun 2023 10:42:04 +0530 Sarath Babu Naidu Gaddam wrote:
> Clock matrix driver can be probed before the rootfs containing
> firmware/initialization .bin is available. The current driver
> throws a warning and proceeds to execute probe even when firmware
> is not ready. Instead, defer probe and wait for the .bin file to
> be available.

The first-step fix should be to try to get the FW into initramfs.
For that driver should specify MODULE_FIRMWARE(), which I don't see
here.
-- 
pw-bot: cr

> -----Original Message-----
> From: Jakub Kicinski <kuba@kernel.org>
> Sent: Friday, June 16, 2023 1:35 AM
> To: Gaddam, Sarath Babu Naidu <sarath.babu.naidu.gaddam@amd.com>
> Cc: richardcochran@gmail.com; netdev@vger.kernel.org;
> simon.horman@corigine.com; andrew@lunn.ch; linux-
> kernel@vger.kernel.org; vincent.cheng.xh@renesas.com; Katakam, Harini
> <harini.katakam@amd.com>; git (AMD-Xilinx) <git@amd.com>
> Subject: Re: [PATCH V2] ptp: clockmatrix: Add Defer probe if firmware
> load fails
> 
> On Wed, 14 Jun 2023 10:42:04 +0530 Sarath Babu Naidu Gaddam wrote:
> > Clock matrix driver can be probed before the rootfs containing
> > firmware/initialization .bin is available. The current driver throws a
> > warning and proceeds to execute probe even when firmware is not
> ready.
> > Instead, defer probe and wait for the .bin file to be available.
> 
> The first-step fix should be to try to get the FW into initramfs.
> For that driver should specify MODULE_FIRMWARE(), which I don't see
> here.

Thanks for the review. We will take MODULE_FIRMWARE as a separate patch.
We want defer probe to go first.

Thanks,
Sarath