linux-kernel - Re: [PATCH] mmc: sdhi: fill in actual

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: <FaBiPuw0MFfdsj60MQTULROSN-8cSV7sNRlgO5SSVPo5jfQopmm9zTq4JT71VxaO32qdcAhisOrhFYG_QLByLNHcBrMgshsI_WwP9rlH2ms=@protonmail.ch>
Date:   Thu, 29 Aug 2019 15:59:46 +0000
From:   Tamás Szűcs <tszucs@...tonmail.ch>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Linux MMC List <linux-mmc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH] mmc: sdhi: fill in actual_clock

Hi Geert,

It would be possible to call clk_get_rate() unconditionally but there's usually no need, thus the ternary. Are you in favor of that though?

It turns out I need to send a followup to fix some glitches. Please stay tuned.

Kind regards,
Tamas


Tamás Szűcs
tszucs@...tonmail.ch

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Thursday, August 29, 2019 9:47 AM, Geert Uytterhoeven <geert@...ux-m68k.org> wrote:

> Hi Tamás,
>
> On Wed, Aug 28, 2019 at 9:02 PM Tamás Szűcs tszucs@...tonmail.ch wrote:
>
> > Save set clock in mmc_host actual_clock enabling exporting it via debugfs.
> > This will indicate the precise SD clock in I/O settings rather than only the
> > sometimes misleading requested clock.
> > Signed-off-by: Tamás Szűcs tszucs@...tonmail.ch
>
> Thanks for your patch!
>
> > --- a/drivers/mmc/host/renesas_sdhi_core.c
> > +++ b/drivers/mmc/host/renesas_sdhi_core.c
> > @@ -124,7 +124,7 @@ static unsigned int renesas_sdhi_clk_update(struct tmio_mmc_host *host,
> > {
> > struct renesas_sdhi *priv = host_to_priv(host);
> > unsigned int freq, diff, best_freq = 0, diff_min = ~0;
> >
> > -         int i, ret;
> >
> >
> >
> > -         int i;
> >
> >           /* tested only on R-Car Gen2+ currently; may work for others */
> >           if (!(host->pdata->flags & TMIO_MMC_MIN_RCAR2))
> >
> >
> >
> > @@ -153,9 +153,11 @@ static unsigned int renesas_sdhi_clk_update(struct tmio_mmc_host *host,
> > }
> > }
> >
> > -         ret = clk_set_rate(priv->clk, best_freq);
> >
> >
> >
> > -         host->mmc->actual_clock =
> >
> >
> > -                 clk_set_rate(priv->clk, best_freq) == 0 ?
> >
> >
> > -                         best_freq : clk_get_rate(priv->clk);
> >
> >
>
> When clk_set_rate() returns 0 to indicate success, it may still have
> rounded the requested clock rate, no?
> So wouldn't it be better to always call clk_get_rate()?
>
> > -         return ret == 0 ? best_freq : clk_get_rate(priv->clk);
> >
> >
> >
> > -         return host->mmc->actual_clock;
> >
> >
> >
> > }
>
> Gr{oetje,eeting}s,
>
> Geert
>
> ----------------------------
>
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds