On Thu, 25 Oct 2018 17:30:26 +0200
Arnd Bergmann [off-list ref] wrote:

On 10/24/18, Boris Brezillon [off-list ref] wrote:

quoted

Hi Arnd,

On Mon, 22 Oct 2018 15:34:01 +0200
Boris Brezillon [off-list ref] wrote:

 

quoted

+
+static void cdns_i3c_master_rd_from_rx_fifo(struct cdns_i3c_master
*master,
+					    u8 *bytes, int nbytes)
+{
+	readsl(master->regs + RX_FIFO, bytes, nbytes / 4);  

Vitor reported a problem with readsl(): this function expects the 2nd
argument to be aligned on 32-bit, which is not guaranteed here. Unless
you see a better solution, I'll switch back to a loop doing:

	for (i = 0; i < nbytes; i += 4) {
		u32 tmp = __raw_readl(...);
		memcpy(bytes + i, &tmp,
		       nbytes - i  > 4 ? 4 : nbytes - i);
	}  

Could we maybe mandate that the buffer itself must be aligned here?
What would be a reason why we see an unaligned target buffer?

Well, the buffers we pass to i3c_send_ccc_cmd() are not necessarily
aligned because they're not dynamically allocated (allocated on the
stack) and are not naturally aligned on 32-bits (either because they
are smaller than 32bits or because the struct is declared __packed).

I guess I could dynamically allocate the payload, but that requires
going over all users of i3c_send_ccc_cmd() to patch them.