linux-kernel - Re: [PATCHv2 4/6] dw_dmac: autoconfigure block

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1348240166.13371.100.camel@smile>
Date:	Fri, 21 Sep 2012 18:09:26 +0300
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	viresh kumar <viresh.kumar@...aro.org>
Cc:	Vinod Koul <vinod.koul@...el.com>, spear-devel@...t.st.com,
	linux-kernel@...r.kernel.org, Hein Tibosch <hein_tibosch@...oo.es>
Subject: Re: [PATCHv2 4/6] dw_dmac: autoconfigure block_size or use platform
 data

On Fri, 2012-09-21 at 19:30 +0530, viresh kumar wrote: 
> On Fri, Sep 21, 2012 at 5:35 PM, Andy Shevchenko
> <andriy.shevchenko@...ux.intel.com> wrote:
> > diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
> > @@ -1385,6 +1375,7 @@ static int __devinit dw_probe(struct platform_device *pdev)
> 
> > +       /* get hardware configuration parameters */
> > +       if (autocfg)
> > +               max_blk_size = dma_readl(dw, MAX_BLK_SIZE);
> > +
> 
> Why don't you do above with the below ++ code
> 
> >         /* Calculate all channel mask before DMA setup */
> >         dw->all_chan_mask = (1 << nr_channels) - 1;
> >
> > @@ -1470,6 +1465,16 @@ static int __devinit dw_probe(struct platform_device *pdev)
> >                 INIT_LIST_HEAD(&dwc->free_list);
> >
> >                 channel_clear_bit(dw, CH_EN, dwc->mask);
> > +
> > +               /* hardware configuration */
> > +               if (autocfg)
> > +                       /* Decode maximum block size for given channel. The
> > +                        * stored 4 bit value represents blocks from 0x00 for 3
> > +                        * up to 0x0a for 4095. */
> 
> i.e. here?
Because there is only one register, but we have loop for channels. Shall
we read the same register as many times as amount of channels we have?

> 
> > +                       dwc->block_size =
> > +                               (4 << ((max_blk_size >> 4 * i) & 0xf)) - 1;
> > +               else
> > +                       dwc->block_size = pdata->block_size;
> >         }

-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/