staging: axis-fifo: remove sysfs interface

 Unhandled fault: imprecise external abort (0x1406) at 0xaec8d000
 [aec8d000] *pgd=03f74831, *pte=0525c75f, *ppte=0525cc7f
 Internal error: Oops - BUG: 1406 [#1] SMP ARM
 Hardware name: Xilinx Zynq Platform
 PC is at sysfs_read+0xc4/0xd8
 LR is at dev_attr_show+0x6c/0xc0
 pc : [<c0ff9298>]    lr : [<c0adad38>]    psr: 60070013
 sp : e09abd18  ip : c3193000  fp : c0adaccc
 r10: 00000000  r9 : c3192000  r8 : 183abab5
 r7 : c1d5d5a8  r6 : c2d71440  r5 : 00000024  r4 : c3192000
 r3 : e0a60024  r2 : 00000000  r1 : c3192000  r0 : c2d71444
 ...
 Call trace:
  sysfs_read from dev_attr_show+0x6c/0xc0
  dev_attr_show from sysfs_kf_seq_show+0x270/0x360
  sysfs_kf_seq_show from seq_read_iter+0x7f4/0x10bc
  seq_read_iter from vfs_read+0x350/0x3d0
  vfs_read from ksys_read+0x104/0x194
  ksys_read from ret_fast_syscall+0x0/0x54

The same abort is triggered if a read is attempted on RDFD register when
the fifo is empty.

Therefore, remove the sysfs interface and only let read()/write() modify
the fifo registers. For debugging purposes, a simple read-only debugfs
interface is added in the next patch.

Fixes: 4a965c5 ("staging: add driver for Xilinx AXI-Stream FIFO v4.1 IP core")
Signed-off-by: Ovidiu Panait <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: ovpanait

drivers/staging/axis-fifo/axis-fifo.c

@@ -139,180 +139,6 @@ struct axis_fifo {
 	struct miscdevice miscdev;
 };
 
-/* ----------------------------
- *         sysfs entries
- * ----------------------------
- */
-
-static ssize_t sysfs_write(struct device *dev, const char *buf,
-			   size_t count, unsigned int addr_offset)
-{
-	struct axis_fifo *fifo = dev_get_drvdata(dev);
-	unsigned long tmp;
-	int rc;
-
-	rc = kstrtoul(buf, 0, &tmp);
-	if (rc < 0)
-		return rc;
-
-	iowrite32(tmp, fifo->base_addr + addr_offset);
-
-	return count;
-}
-
-static ssize_t sysfs_read(struct device *dev, char *buf,
-			  unsigned int addr_offset)
-{
-	struct axis_fifo *fifo = dev_get_drvdata(dev);
-	unsigned int read_val;
-
-	read_val = ioread32(fifo->base_addr + addr_offset);
-	return sysfs_emit(buf, "0x%x\n", read_val);
-}
-
-static ssize_t isr_store(struct device *dev, struct device_attribute *attr,
-			 const char *buf, size_t count)
-{
-	return sysfs_write(dev, buf, count, XLLF_ISR_OFFSET);
-}
-
-static ssize_t isr_show(struct device *dev,
-			struct device_attribute *attr, char *buf)
-{
-	return sysfs_read(dev, buf, XLLF_ISR_OFFSET);
-}
-
-static DEVICE_ATTR_RW(isr);
-
-static ssize_t ier_store(struct device *dev, struct device_attribute *attr,
-			 const char *buf, size_t count)
-{
-	return sysfs_write(dev, buf, count, XLLF_IER_OFFSET);
-}
-
-static ssize_t ier_show(struct device *dev,
-			struct device_attribute *attr, char *buf)
-{
-	return sysfs_read(dev, buf, XLLF_IER_OFFSET);
-}
-
-static DEVICE_ATTR_RW(ier);
-
-static ssize_t tdfr_store(struct device *dev, struct device_attribute *attr,
-			  const char *buf, size_t count)
-{
-	return sysfs_write(dev, buf, count, XLLF_TDFR_OFFSET);
-}
-
-static DEVICE_ATTR_WO(tdfr);
-
-static ssize_t tdfv_show(struct device *dev,
-			 struct device_attribute *attr, char *buf)
-{
-	return sysfs_read(dev, buf, XLLF_TDFV_OFFSET);
-}
-
-static DEVICE_ATTR_RO(tdfv);
-
-static ssize_t tdfd_store(struct device *dev, struct device_attribute *attr,
-			  const char *buf, size_t count)
-{
-	return sysfs_write(dev, buf, count, XLLF_TDFD_OFFSET);
-}
-
-static DEVICE_ATTR_WO(tdfd);
-
-static ssize_t tlr_store(struct device *dev, struct device_attribute *attr,
-			 const char *buf, size_t count)
-{
-	return sysfs_write(dev, buf, count, XLLF_TLR_OFFSET);
-}
-
-static DEVICE_ATTR_WO(tlr);
-
-static ssize_t rdfr_store(struct device *dev, struct device_attribute *attr,
-			  const char *buf, size_t count)
-{
-	return sysfs_write(dev, buf, count, XLLF_RDFR_OFFSET);
-}
-
-static DEVICE_ATTR_WO(rdfr);
-
-static ssize_t rdfo_show(struct device *dev,
-			 struct device_attribute *attr, char *buf)
-{
-	return sysfs_read(dev, buf, XLLF_RDFO_OFFSET);
-}
-
-static DEVICE_ATTR_RO(rdfo);
-
-static ssize_t rdfd_show(struct device *dev,
-			 struct device_attribute *attr, char *buf)
-{
-	return sysfs_read(dev, buf, XLLF_RDFD_OFFSET);
-}
-
-static DEVICE_ATTR_RO(rdfd);
-
-static ssize_t rlr_show(struct device *dev,
-			struct device_attribute *attr, char *buf)
-{
-	return sysfs_read(dev, buf, XLLF_RLR_OFFSET);
-}
-
-static DEVICE_ATTR_RO(rlr);
-
-static ssize_t srr_store(struct device *dev, struct device_attribute *attr,
-			 const char *buf, size_t count)
-{
-	return sysfs_write(dev, buf, count, XLLF_SRR_OFFSET);
-}
-
-static DEVICE_ATTR_WO(srr);
-
-static ssize_t tdr_store(struct device *dev, struct device_attribute *attr,
-			 const char *buf, size_t count)
-{
-	return sysfs_write(dev, buf, count, XLLF_TDR_OFFSET);
-}
-
-static DEVICE_ATTR_WO(tdr);
-
-static ssize_t rdr_show(struct device *dev,
-			struct device_attribute *attr, char *buf)
-{
-	return sysfs_read(dev, buf, XLLF_RDR_OFFSET);
-}
-
-static DEVICE_ATTR_RO(rdr);
-
-static struct attribute *axis_fifo_attrs[] = {
-	&dev_attr_isr.attr,
-	&dev_attr_ier.attr,
-	&dev_attr_tdfr.attr,
-	&dev_attr_tdfv.attr,
-	&dev_attr_tdfd.attr,
-	&dev_attr_tlr.attr,
-	&dev_attr_rdfr.attr,
-	&dev_attr_rdfo.attr,
-	&dev_attr_rdfd.attr,
-	&dev_attr_rlr.attr,
-	&dev_attr_srr.attr,
-	&dev_attr_tdr.attr,
-	&dev_attr_rdr.attr,
-	NULL,
-};
-
-static const struct attribute_group axis_fifo_attrs_group = {
-	.name = "ip_registers",
-	.attrs = axis_fifo_attrs,
-};
-
-static const struct attribute_group *axis_fifo_attrs_groups[] = {
-	&axis_fifo_attrs_group,
-	NULL,
-};
-
 /* ----------------------------
  *        implementation
  * ----------------------------
@@ -877,7 +703,6 @@ static int axis_fifo_probe(struct platform_device *pdev)
 	fifo->miscdev.fops = &fops;
 	fifo->miscdev.minor = MISC_DYNAMIC_MINOR;
 	fifo->miscdev.name = device_name;
-	fifo->miscdev.groups = axis_fifo_attrs_groups;
 	fifo->miscdev.parent = dev;
 	rc = misc_register(&fifo->miscdev);
 	if (rc < 0)