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staging: axis-fifo: Remove hardware resets for user errors
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The axis-fifo driver performs a full hardware reset (via
reset_ip_core()) in several error paths within the read and write
functions. This reset flushes both TX and RX FIFOs and resets the
AXI-Stream links.

Allow the user to handle the error without causing hardware disruption
or data loss in other FIFO paths.

Fixes: 4a965c5 ("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/20250419004306.669605-1-gshahrouzi@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Gabriel Shahrouzi authored and Greg Kroah-Hartman committed Apr 25, 2025
1 parent 2ca34b5 commit c6e8d85
Showing 1 changed file with 3 additions and 8 deletions.
11 changes: 3 additions & 8 deletions drivers/staging/axis-fifo/axis-fifo.c
Original file line number Diff line number Diff line change
Expand Up @@ -393,16 +393,14 @@ static ssize_t axis_fifo_read(struct file *f, char __user *buf,

bytes_available = ioread32(fifo->base_addr + XLLF_RLR_OFFSET);
if (!bytes_available) {
dev_err(fifo->dt_device, "received a packet of length 0 - fifo core will be reset\n");
reset_ip_core(fifo);
dev_err(fifo->dt_device, "received a packet of length 0\n");
ret = -EIO;
goto end_unlock;
}

if (bytes_available > len) {
dev_err(fifo->dt_device, "user read buffer too small (available bytes=%zu user buffer bytes=%zu) - fifo core will be reset\n",
dev_err(fifo->dt_device, "user read buffer too small (available bytes=%zu user buffer bytes=%zu)\n",
bytes_available, len);
reset_ip_core(fifo);
ret = -EINVAL;
goto end_unlock;
}
Expand All @@ -411,8 +409,7 @@ static ssize_t axis_fifo_read(struct file *f, char __user *buf,
/* this probably can't happen unless IP
* registers were previously mishandled
*/
dev_err(fifo->dt_device, "received a packet that isn't word-aligned - fifo core will be reset\n");
reset_ip_core(fifo);
dev_err(fifo->dt_device, "received a packet that isn't word-aligned\n");
ret = -EIO;
goto end_unlock;
}
Expand All @@ -433,7 +430,6 @@ static ssize_t axis_fifo_read(struct file *f, char __user *buf,

if (copy_to_user(buf + copied * sizeof(u32), tmp_buf,
copy * sizeof(u32))) {
reset_ip_core(fifo);
ret = -EFAULT;
goto end_unlock;
}
Expand Down Expand Up @@ -542,7 +538,6 @@ static ssize_t axis_fifo_write(struct file *f, const char __user *buf,

if (copy_from_user(tmp_buf, buf + copied * sizeof(u32),
copy * sizeof(u32))) {
reset_ip_core(fifo);
ret = -EFAULT;
goto end_unlock;
}
Expand Down

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