On Thu, Feb 20, 2025 at 02:11:06PM +0800, Stanley Chu wrote:
> From: Stanley Chu <yschu@xxxxxxxxxxx>
>
> I3C HW stalls the write transfer if the transmit FIFO becomes empty,
> when new data is written to FIFO, I3C HW resumes the transfer but the
> first transmitted data bit may have the wrong value.
> Fill the FIFO in advance to prevent FIFO from becoming empty.
>
> Signed-off-by: Stanley Chu <yschu@xxxxxxxxxxx>
> ---
You missed do_daa part.
> drivers/i3c/master/svc-i3c-master.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
> index c58440061d5a..2140da3f5187 100644
> --- a/drivers/i3c/master/svc-i3c-master.c
> +++ b/drivers/i3c/master/svc-i3c-master.c
> @@ -1196,8 +1196,8 @@ static int svc_i3c_master_read(struct svc_i3c_master *master,
> return offset;
> }
>
> -static int svc_i3c_master_write(struct svc_i3c_master *master,
> - const u8 *out, unsigned int len)
> +static int svc_i3c_master_write(struct svc_i3c_master *master, const u8 *out,
> + unsigned int len, bool last)
> {
> int offset = 0, ret;
> u32 mdctrl;
> @@ -1214,7 +1214,7 @@ static int svc_i3c_master_write(struct svc_i3c_master *master,
> * The last byte to be sent over the bus must either have the
> * "end" bit set or be written in MWDATABE.
> */
> - if (likely(offset < (len - 1)))
> + if (likely(offset < (len - 1)) || !last)
> writel(out[offset++], master->regs + SVC_I3C_MWDATAB);
> else
> writel(out[offset++], master->regs + SVC_I3C_MWDATABE);
> @@ -1245,6 +1245,19 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
> SVC_I3C_MCTRL_RDTERM(*actual_len),
> master->regs + SVC_I3C_MCTRL);
>
> + if ((master->quirks & SVC_I3C_QUIRK_FIFO_EMPTY) && !rnw && xfer_len) {
> + unsigned int len = xfer_len;
len = max_t(u32, xfer_len, SVC_I3C_FIFO_SIZE);
> +
> + if (xfer_len > SVC_I3C_FIFO_SIZE)
> + len = SVC_I3C_FIFO_SIZE;
> + ret = svc_i3c_master_write(master, out, len,
> + xfer_len <= SVC_I3C_FIFO_SIZE);
> + if (ret < 0)
> + goto emit_stop;
> + xfer_len -= len;
> + out += len;
> + }
> +
> ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg,
> SVC_I3C_MSTATUS_MCTRLDONE(reg), 0, 1000);
> if (ret)
> @@ -1306,7 +1319,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
> if (rnw)
> ret = svc_i3c_master_read(master, in, xfer_len);
> else
> - ret = svc_i3c_master_write(master, out, xfer_len);
> + ret = svc_i3c_master_write(master, out, xfer_len, true);
> if (ret < 0)
> goto emit_stop;
>
> @@ -1333,6 +1346,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
> emit_stop:
> svc_i3c_master_emit_stop(master);
> svc_i3c_master_clear_merrwarn(master);
> + svc_i3c_master_flush_fifo(master);
>
> return ret;
> }
> --
> 2.34.1
>
