在 2025/3/3 18:51, Sudeep Holla 写道:
The Sparse static checker flags a type mismatch warning related to
endianness conversion:
| warning: incorrect type in argument 1 (different base types)
| expected restricted __le32 const [usertype] *p
| got unsigned int *
This is because an explicit endianness conversion (le32_to_cpu()) was
applied unnecessarily to a pcc_hdr.flags field that is already in
little-endian format.
The PCC driver is only enabled on little-endian kernels due to its
dependency on ACPI and EFI, making the explicit conversion unnecessary.
How to confirm ACPI works only on little-endian?
The redundant conversion occurs in pcc_chan_check_and_ack() for the
pcc_hdr.flags field. Drop this unnecessary endianness conversion of
pcc_hdr.flags.
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
---
drivers/mailbox/pcc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index 4c582fa2b8bf4c9a9368dba8220f567555dba963..c87a5b7fa6eaf7bcabe0d55f844961c499376938 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -292,7 +292,7 @@ static void check_and_ack(struct pcc_chan_info *pchan, struct mbox_chan *chan)
*
* The PCC master subspace channel clears chan_in_use to free channel.
*/
- if (le32_to_cpup(&pcc_hdr.flags) & PCC_ACK_FLAG_MASK)
+ if (pcc_hdr.flags & PCC_ACK_FLAG_MASK)
It's recommanded to delete PCC_ACK_FLAG_MASK and use
PCC_CMD_COMPLETION_NOTIFY.
They are from the same place, namely, 'Initiator Responder
Communications Channel Flags'.
pcc_send_data(chan, NULL);
else
pcc_chan_reg_read_modify_write(&pchan->cmd_update);
