Messages in this thread | | | Date | Fri, 16 Jul 2021 00:55:52 +0200 | From | Miquel Raynal <> | Subject | Re: [PATCH 3/4] i3c: master: svc: add support for slave to stop returning data |
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Hi Clark,
Clark Wang <xiaoning.wang@nxp.com> wrote on Thu, 15 Jul 2021 16:24:12 +0800:
> When i3c controller reads data from slave device, slave device can stop > returning data with an ACK after any byte. > Add this support for svc i3c controller. Otherwise, it will go TIMEOUT > error path when the slave device ends the read operation early.
Is this part of the I3C specification? I am not aware about it.
> Signed-off-by: Clark Wang <xiaoning.wang@nxp.com> > --- > drivers/i3c/master/svc-i3c-master.c | 28 ++++++++++++++++++++-------- > 1 file changed, 20 insertions(+), 8 deletions(-) > > diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c > index 9d80435638ea..892e57fec4b0 100644 > --- a/drivers/i3c/master/svc-i3c-master.c > +++ b/drivers/i3c/master/svc-i3c-master.c > @@ -865,7 +865,7 @@ static int svc_i3c_master_read(struct svc_i3c_master *master, > u8 *in, unsigned int len) > { > int offset = 0, i, ret; > - u32 mdctrl; > + u32 mdctrl, mstatus; > > while (offset < len) { > unsigned int count; > @@ -874,8 +874,15 @@ static int svc_i3c_master_read(struct svc_i3c_master *master, > mdctrl, > !(mdctrl & SVC_I3C_MDATACTRL_RXEMPTY), > 0, 1000); > - if (ret) > - return ret; > + if (ret) { > + ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, > + mstatus, SVC_I3C_MSTATUS_COMPLETE(mstatus), > + 0, 1000); > + if (ret) > + return ret; > + else > + return offset; > + } > > count = SVC_I3C_MDATACTRL_RXCOUNT(mdctrl); > for (i = 0; i < count; i++) > @@ -884,7 +891,7 @@ static int svc_i3c_master_read(struct svc_i3c_master *master, > offset += count; > } > > - return 0; > + return offset; > } > > static int svc_i3c_master_write(struct svc_i3c_master *master, > @@ -917,7 +924,7 @@ static int svc_i3c_master_write(struct svc_i3c_master *master, > static int svc_i3c_master_xfer(struct svc_i3c_master *master, > bool rnw, unsigned int xfer_type, u8 addr, > u8 *in, const u8 *out, unsigned int xfer_len, > - unsigned int read_len, bool continued) > + unsigned int *read_len, bool continued) > { > u32 reg; > int ret; > @@ -927,7 +934,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master, > SVC_I3C_MCTRL_IBIRESP_NACK | > SVC_I3C_MCTRL_DIR(rnw) | > SVC_I3C_MCTRL_ADDR(addr) | > - SVC_I3C_MCTRL_RDTERM(read_len), > + SVC_I3C_MCTRL_RDTERM(*read_len), > master->regs + SVC_I3C_MCTRL); > > ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg, > @@ -939,8 +946,10 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master, > ret = svc_i3c_master_read(master, in, xfer_len); > else > ret = svc_i3c_master_write(master, out, xfer_len); > - if (ret) > + if (ret < 0) > goto emit_stop; > + if (rnw) > + *read_len = ret; > > ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg, > SVC_I3C_MSTATUS_COMPLETE(reg), 0, 1000); > @@ -1012,7 +1021,7 @@ static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master) > > ret = svc_i3c_master_xfer(master, cmd->rnw, xfer->type, > cmd->addr, cmd->in, cmd->out, > - cmd->len, cmd->read_len, > + cmd->len, &cmd->read_len, > cmd->continued); > if (ret) > break; > @@ -1141,6 +1150,9 @@ static int svc_i3c_master_send_direct_ccc_cmd(struct svc_i3c_master *master, > if (!wait_for_completion_timeout(&xfer->comp, msecs_to_jiffies(1000))) > svc_i3c_master_dequeue_xfer(master, xfer); > > + if (cmd->read_len != xfer_len) > + ccc->dests[0].payload.len = cmd->read_len; > + > ret = xfer->ret; > svc_i3c_master_free_xfer(xfer); >
Thanks, Miquèl
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