Re: [PATCH 00/14] usb: typec: UCSI driver overhaul

[Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>]

On Fri, Sep 27, 2019 at 12:13:57AM +0000, Ajay Gupta wrote:
> Hi Heikki,
> > -----Original Message-----
> > From: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> > Sent: Thursday, September 26, 2019 3:07 AM
> > To: Ajay Gupta <ajayg@xxxxxxxxxx>
> > Cc: linux-usb@xxxxxxxxxxxxxxx
> > Subject: [PATCH 00/14] usb: typec: UCSI driver overhaul
> > 
> > Hi Ajay,
> > 
> > Here's the pretty much complete rewrite of the I/O handling that I was
> > talking about. The first seven patches are not actually related to
> > this stuff, but I'm including them here because the rest of the series
> > is made on top of them. I'm including also that fix patch I send you
> > earlier.
> > 
> > After this it should be easier to handle quirks. My idea how to handle
> > the multi-instance connector alt modes is that we "emulate" the PPM in
> > ucsi_ccg.c in order to handle them, so ucsi.c is not touched at all.
> > 
> > We can now get the connector alternate modes that the actual
> > controller supplies during probe - before registering the ucsi
> > interface - and squash all alt modes with the same SVID into one that
> > we supply to the ucsi.c when ever it sends GET_ALTERNATE_MODES
> > command. Also other alt mode commands like SET_NEW_CAM can have
> > special processing in ucsi_ccg.c and ucsi_ccg.c alone. There should
> > not be any problem with that anymore.
> I took the changes and loaded on my GPU system and do not see
> altmode devices under /sys/bus/typec/devices/*. Its empty.
> 
> Below error is seen
> "ucsi_ccg 4-0008: con1: failed to register alternate modes"
> 
> ucsi_run_command() is returning -16.
> 
> I will review the ccg changes and try to debug above issue.

I tested this series with the NVIDIA GPU PCI card that we have. The
controller is reporting BUSY as responce to the GET_ALTERNATE_MODES
command. I added a loop to ucsi_exec_command() where I read the CCI
until the there is no UCSI_CCI_BUSY bit set, and it seems to work.

Here are both changes:

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index accf54d987ad..d70ee8006c34 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -102,6 +102,7 @@ static int ucsi_read_error(struct ucsi *ucsi)

 static int ucsi_exec_command(struct ucsi *ucsi, u64 cmd)
 {
+       unsigned long timeout;
        u32 cci;
        int ret;

@@ -109,12 +110,15 @@ static int ucsi_exec_command(struct ucsi *ucsi, u64 cmd)
        if (ret)
                return ret;

-       ret = ucsi->ops->read(ucsi, UCSI_CCI, &cci, sizeof(cci));
-       if (ret)
-               return ret;
+       timeout = jiffies + msecs_to_jiffies(UCSI_TIMEOUT_MS);
+       do {
+               if (time_is_before_jiffies(timeout))
+                       return -ETIMEDOUT;

-       if (cci & UCSI_CCI_BUSY)
-               return -EBUSY;
+               ret = ucsi->ops->read(ucsi, UCSI_CCI, &cci, sizeof(cci));
+               if (ret)
+                       return ret;
+       } while (cci & UCSI_CCI_BUSY);

        if (!(cci & UCSI_CCI_COMMAND_COMPLETE))
                return -EIO;
@@ -330,7 +334,7 @@ static int ucsi_register_altmodes(struct ucsi_connector *con, u8 recipient)
                command |= UCSI_GET_ALTMODE_RECIPIENT(recipient);
                command |= UCSI_GET_ALTMODE_CONNECTOR_NUMBER(con->num);
                command |= UCSI_GET_ALTMODE_OFFSET(i);
-               command |= UCSI_GET_ALTMODE_NUM_ALTMODES(1); /* One at a time */
+
                len = ucsi_run_command(con->ucsi, command, alt, sizeof(alt));
                if (len <= 0)
                        return len;

Let me know if that works.

thanks,

-- 
heikki