RE: [PATCH v5] ssi: xilinx_spips: Skip spi bus update for a few register writes

[Sai Pavan Boddu <saipava@xilinx.com>]

Thanks Francisco & Alistair for review.
I have sent V6 with Review tags and commit message fix.

Regards,
Sai Pavan

> -----Original Message-----
> From: Francisco Iglesias <frasse.iglesias@gmail.com>
> Sent: Friday, October 25, 2019 6:47 PM
> To: Sai Pavan Boddu <saipava@xilinx.com>
> Cc: Alistair Francis <alistair@alistair23.me>; Peter Maydell
> <peter.maydell@linaro.org>; Edgar Iglesias <edgari@xilinx.com>; qemu-
> devel@nongnu.org
> Subject: Re: [PATCH v5] ssi: xilinx_spips: Skip spi bus update for a few register
> writes
> 
> Hi Sai,
> 
> On [2019 Oct 25] Fri 11:02:11, Sai Pavan Boddu wrote:
> > A few configuration register writes need not update the spi bus state,
> > so just return after register write.
> 
> s/register write/the register write/
> 
> >
> > Signed-off-by: Sai Pavan Boddu <sai.pavan.boddu@xilinx.com>
> 
> After above change:
> 
> Reviewed-by: Francisco Iglesias <frasse.iglesias@gmail.com>
> Tested-by: Francisco Iglesias <frasse.iglesias@gmail.com>
> 
> Best regards,
> Francisco Iglesias
> 
> > ---
> >
> > Changes for V2:
> > 	Just skip update of spips cs and fifos
> > 	Update commit message accordingly
> > Changes for V4:
> > 	Avoid checking for zynqmp qspi
> > 	Skip spi bus update for few of the registers Changes for V4:
> > 	Move the register list to existing switch case above.
> > Change for V5:
> > 	Fixed Commit message.
> >
> >  hw/ssi/xilinx_spips.c | 22 ++++++++++++++++++----
> >  1 file changed, 18 insertions(+), 4 deletions(-)
> >
> > diff --git a/hw/ssi/xilinx_spips.c b/hw/ssi/xilinx_spips.c index
> > a309c71..0d6c2e1 100644
> > --- a/hw/ssi/xilinx_spips.c
> > +++ b/hw/ssi/xilinx_spips.c
> > @@ -109,6 +109,7 @@
> >  #define R_GPIO              (0x30 / 4)
> >  #define R_LPBK_DLY_ADJ      (0x38 / 4)
> >  #define R_LPBK_DLY_ADJ_RESET (0x33)
> > +#define R_IOU_TAPDLY_BYPASS (0x3C / 4)
> >  #define R_TXD1              (0x80 / 4)
> >  #define R_TXD2              (0x84 / 4)
> >  #define R_TXD3              (0x88 / 4)
> > @@ -139,6 +140,8 @@
> >  #define R_LQSPI_STS         (0xA4 / 4)
> >  #define LQSPI_STS_WR_RECVD      (1 << 1)
> >
> > +#define R_DUMMY_CYCLE_EN    (0xC8 / 4)
> > +#define R_ECO               (0xF8 / 4)
> >  #define R_MOD_ID            (0xFC / 4)
> >
> >  #define R_GQSPI_SELECT          (0x144 / 4)
> > @@ -970,6 +973,7 @@ static void xilinx_spips_write(void *opaque,
> > hwaddr addr,  {
> >      int mask = ~0;
> >      XilinxSPIPS *s = opaque;
> > +    bool try_flush = true;
> >
> >      DB_PRINT_L(0, "addr=" TARGET_FMT_plx " = %x\n", addr,
> (unsigned)value);
> >      addr >>= 2;
> > @@ -1019,13 +1023,23 @@ static void xilinx_spips_write(void *opaque,
> hwaddr addr,
> >          tx_data_bytes(&s->tx_fifo, (uint32_t)value, 3,
> >                        s->regs[R_CONFIG] & R_CONFIG_ENDIAN);
> >          goto no_reg_update;
> > +    /* Skip SPI bus update for below registers writes */
> > +    case R_GPIO:
> > +    case R_LPBK_DLY_ADJ:
> > +    case R_IOU_TAPDLY_BYPASS:
> > +    case R_DUMMY_CYCLE_EN:
> > +    case R_ECO:
> > +        try_flush = false;
> > +        break;
> >      }
> >      s->regs[addr] = (s->regs[addr] & ~mask) | (value & mask);
> >  no_reg_update:
> > -    xilinx_spips_update_cs_lines(s);
> > -    xilinx_spips_check_flush(s);
> > -    xilinx_spips_update_cs_lines(s);
> > -    xilinx_spips_update_ixr(s);
> > +    if (try_flush) {
> > +        xilinx_spips_update_cs_lines(s);
> > +        xilinx_spips_check_flush(s);
> > +        xilinx_spips_update_cs_lines(s);
> > +        xilinx_spips_update_ixr(s);
> > +    }
> >  }
> >
> >  static const MemoryRegionOps spips_ops = {
> > --
> > 2.7.4
> >