Commit cd77d5a4 authored by Lizhi Hou's avatar Lizhi Hou
Browse files

accel/amdxdna: Fix tail-pointer polling in mailbox_get_msg() 



In mailbox_get_msg(), mailbox_reg_read_non_zero() is called to poll for a
non-zero tail pointer. This assumed that a zero value indicates an error.
However, certain corner cases legitimately produce a zero tail pointer.
To handle these cases, remove mailbox_reg_read_non_zero(). The zero tail
pointer will be treated as a valid rewind event.

Reviewed-by: default avatarMaciej Falkowski <maciej.falkowski@linux.intel.com>
Signed-off-by: default avatarLizhi Hou <lizhi.hou@amd.com>
Link: https://patch.msgid.link/20251204181603.793824-1-lizhi.hou@amd.com
parent 646013f5

drivers/accel/amdxdna/amdxdna_mailbox.c

+1 −18
Original line number Diff line number Diff line
@@ -112,22 +112,6 @@ static u32 mailbox_reg_read(struct mailbox_channel *mb_chann, u32 mbox_reg) 
	return readl(ringbuf_addr);

}



static int mailbox_reg_read_non_zero(struct mailbox_channel *mb_chann, u32 mbox_reg, u32 *val)

{

	struct xdna_mailbox_res *mb_res = &mb_chann->mb->res;

	void __iomem *ringbuf_addr = mb_res->mbox_base + mbox_reg;

	int ret, value;



	/* Poll till value is not zero */

	ret = readx_poll_timeout(readl, ringbuf_addr, value,

				 value, 1 /* us */, 100);

	if (ret < 0)

		return ret;



	*val = value;

	return 0;

}



static inline void

mailbox_set_headptr(struct mailbox_channel *mb_chann, u32 headptr_val)

{
@@ -286,8 +270,7 @@ static int mailbox_get_msg(struct mailbox_channel *mb_chann) 
	u32 start_addr;

	int ret;



	if (mailbox_reg_read_non_zero(mb_chann, mb_chann->res[CHAN_RES_I2X].mb_tail_ptr_reg, &tail))

		return -EINVAL;

	tail = mailbox_get_tailptr(mb_chann, CHAN_RES_I2X);

	head = mb_chann->i2x_head;

	ringbuf_size = mailbox_get_ringbuf_size(mb_chann, CHAN_RES_I2X);

	start_addr = mb_chann->res[CHAN_RES_I2X].rb_start_addr;