| Message ID | 1534796770-10295-8-git-send-email-minyard@acm.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,01/10] i2c:pm_smbus: Clean up some style issues | expand |
On 08/20/2018 05:26 PM, minyard@acm.org wrote: > From: Corey Minyard <cminyard@mvista.com> > > Change 880b1ffe6ec2f0ae "smbus: do not immediately complete commands" > changed pm_smbus to delay setting the host busy bit until the status > register was read, to work around a bug in AMIBIOS. Unfortunately, > when interrupts are enabled, the status register will never get read > and the processing will never happen. > > Modify the code to only delay setting the host busy bit if interrupts > are not enabled. > > Signed-off-by: Corey Minyard <cminyard@mvista.com> > Cc: Hervé Poussineau <hpoussin@reactos.org> > Cc: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > --- > hw/i2c/pm_smbus.c | 19 +++++++++++++------ > 1 file changed, 13 insertions(+), 6 deletions(-) > > diff --git a/hw/i2c/pm_smbus.c b/hw/i2c/pm_smbus.c > index 664a6b1..10ba208 100644 > --- a/hw/i2c/pm_smbus.c > +++ b/hw/i2c/pm_smbus.c > @@ -80,9 +80,6 @@ static void smb_transaction(PMSMBus *s) > I2CBus *bus = s->smbus; > int ret; > > - assert(s->smb_stat & STS_HOST_BUSY); > - s->smb_stat &= ~STS_HOST_BUSY; > - > SMBUS_DPRINTF("SMBus trans addr=0x%02x prot=0x%02x\n", addr, prot); > /* Transaction isn't exec if STS_DEV_ERR bit set */ > if ((s->smb_stat & STS_DEV_ERR) != 0) { > @@ -209,9 +206,18 @@ error: > > static void smb_transaction_start(PMSMBus *s) > { > - /* Do not execute immediately the command ; it will be > - * executed when guest will read SMB_STAT register */ > - s->smb_stat |= STS_HOST_BUSY; > + if (s->smb_ctl & CTL_INTREN) { > + smb_transaction(s); > + } else { > + /* Do not execute immediately the command; it will be > + * executed when guest will read SMB_STAT register. This > + * is to work around a bug in AMIBIOS (that is working > + * around another bug in some specific hardware) where > + * it waits for STS_HOST_BUSY to be set before waiting > + * checking for status. If STS_HOST_BUSY doesn't get > + * set, it gets stuck. */ > + s->smb_stat |= STS_HOST_BUSY; > + } > } > > static bool > @@ -330,6 +336,7 @@ static uint64_t smb_ioport_readb(void *opaque, hwaddr addr, unsigned width) > val = s->smb_stat; > if (s->smb_stat & STS_HOST_BUSY) { > /* execute command now */ > + s->smb_stat &= ~STS_HOST_BUSY; > smb_transaction(s); > } > break; >
diff --git a/hw/i2c/pm_smbus.c b/hw/i2c/pm_smbus.c index 664a6b1..10ba208 100644 --- a/hw/i2c/pm_smbus.c +++ b/hw/i2c/pm_smbus.c @@ -80,9 +80,6 @@ static void smb_transaction(PMSMBus *s) I2CBus *bus = s->smbus; int ret; - assert(s->smb_stat & STS_HOST_BUSY); - s->smb_stat &= ~STS_HOST_BUSY; - SMBUS_DPRINTF("SMBus trans addr=0x%02x prot=0x%02x\n", addr, prot); /* Transaction isn't exec if STS_DEV_ERR bit set */ if ((s->smb_stat & STS_DEV_ERR) != 0) { @@ -209,9 +206,18 @@ error: static void smb_transaction_start(PMSMBus *s) { - /* Do not execute immediately the command ; it will be - * executed when guest will read SMB_STAT register */ - s->smb_stat |= STS_HOST_BUSY; + if (s->smb_ctl & CTL_INTREN) { + smb_transaction(s); + } else { + /* Do not execute immediately the command; it will be + * executed when guest will read SMB_STAT register. This + * is to work around a bug in AMIBIOS (that is working + * around another bug in some specific hardware) where + * it waits for STS_HOST_BUSY to be set before waiting + * checking for status. If STS_HOST_BUSY doesn't get + * set, it gets stuck. */ + s->smb_stat |= STS_HOST_BUSY; + } } static bool @@ -330,6 +336,7 @@ static uint64_t smb_ioport_readb(void *opaque, hwaddr addr, unsigned width) val = s->smb_stat; if (s->smb_stat & STS_HOST_BUSY) { /* execute command now */ + s->smb_stat &= ~STS_HOST_BUSY; smb_transaction(s); } break;