FAILED: patch "[PATCH] staging: axis-fifo: Correct handling of tx_fifo_depth for" failed to apply to 5.4-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 2ca34b508774aaa590fc3698a54204706ecca4ba
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025051209-visible-hassle-6995@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2ca34b508774aaa590fc3698a54204706ecca4ba Mon Sep 17 00:00:00 2001
From: Gabriel Shahrouzi <gshahrouzi@gmail.com>
Date: Fri, 18 Apr 2025 21:29:37 -0400
Subject: [PATCH] staging: axis-fifo: Correct handling of tx_fifo_depth for
 size validation

Remove erroneous subtraction of 4 from the total FIFO depth read from
device tree. The stored depth is for checking against total capacity,
not initial vacancy. This prevented writes near the FIFO's full size.

The check performed just before data transfer, which uses live reads of
the TDFV register to determine current vacancy, correctly handles the
initial Depth - 4 hardware state and subsequent FIFO fullness.

Fixes: 4a965c5f89de ("staging: add driver for Xilinx AXI-Stream FIFO v4.1 IP core")
Cc: stable@vger.kernel.org
Signed-off-by: Gabriel Shahrouzi <gshahrouzi@gmail.com>
Link: https://lore.kernel.org/r/20250419012937.674924-1-gshahrouzi@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/axis-fifo/axis-fifo.c b/drivers/staging/axis-fifo/axis-fifo.c
index 7540c20090c7..04b3dc3cfe7c 100644
--- a/drivers/staging/axis-fifo/axis-fifo.c
+++ b/drivers/staging/axis-fifo/axis-fifo.c
@@ -775,9 +775,6 @@ static int axis_fifo_parse_dt(struct axis_fifo *fifo)
 		goto end;
 	}
 
-	/* IP sets TDFV to fifo depth - 4 so we will do the same */
-	fifo->tx_fifo_depth -= 4;
-
 	ret = get_dts_property(fifo, "xlnx,use-rx-data", &fifo->has_rx_fifo);
 	if (ret) {
 		dev_err(fifo->dt_device, "missing xlnx,use-rx-data property\n");