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

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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: Maciej Falkowski <maciej.falkowski@linux.intel.com>
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Link: https://patch.msgid.link/20251204181603.793824-1-lizhi.hou@amd.com
This commit is contained in:
Lizhi Hou 2025-12-04 10:16:03 -08:00
parent 646013f513
commit cd77d5a4aa
1 changed files with 1 additions and 18 deletions
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19
drivers/accel/amdxdna/amdxdna_mailbox.c
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@ -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;