From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Nguyen An Hoan <na-hoan@jinso.co.jp>
Cc: Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
"Mark Brown" <broonie@kernel.org>,
"Geert Uytterhoeven" <geert+renesas@glider.be>,
"Magnus Damm" <magnus.damm@gmail.com>,
linux-spi <linux-spi@vger.kernel.org>,
"Kuninori Morimoto" <kuninori.morimoto.gx@renesas.com>,
"Yoshihiro Shimoda" <yoshihiro.shimoda.uh@renesas.com>,
稲吉 <h-inayoshi@jinso.co.jp>, Dung:人ソ <nv-dung@jinso.co.jp>,
カオ・ヴァン・ドン <cv-dong@jinso.co.jp>
Subject: Re: [PATCH 2/2] spi: sh-msiof: Use DMA if possible
Date: Fri, 11 Jan 2019 10:09:10 +0100 [thread overview]
Message-ID: <CAMuHMdUAk004J-06o43yHei10tWCkyztsWUXUyCj36cPwT9D0w@mail.gmail.com> (raw)
In-Reply-To: <1547197109-637-2-git-send-email-na-hoan@jinso.co.jp>
Hi Hoan-san,
On Fri, Jan 11, 2019 at 9:59 AM Nguyen An Hoan <na-hoan@jinso.co.jp> wrote:
> From: Hoan Nguyen An <na-hoan@jinso.co.jp>
>
> Currently, this driver only supports feature for DMA 32-bits.
> In this case, only if the data length is divisible by 4 to use
> DMA, otherwise PIO will be used. This patch will suggest use
> the DMA 32-bits with 4bytes of words, then the remaining data
> will be transmitted by PIO mode.
>
> Signed-off-by: Hoan Nguyen An <na-hoan@jinso.co.jp>
Thanks for your patch, that's a great idea!
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
with a small suggestion below.
> --- a/drivers/spi/spi-sh-msiof.c
> +++ b/drivers/spi/spi-sh-msiof.c
> @@ -937,17 +937,13 @@ static int sh_msiof_transfer_one(struct spi_master *master,
> unsigned int l = 0;
>
> if (tx_buf)
> - l = min(len, p->tx_fifo_size * 4);
> + l = min(len - len % 4, p->tx_fifo_size * 4);
I think this would be easier to read when written as:
l = min(round_down(len, 4), p->tx_fifo_size * 4);
> if (rx_buf)
> - l = min(len, p->rx_fifo_size * 4);
> + l = min(len - len % 4, p->rx_fifo_size * 4);
Likewise,
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-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
next prev parent reply other threads:[~2019-01-11 9:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-11 8:58 [PATCH 1/2] spi: sh-msiof: fix *info pointer in request_dma() Nguyen An Hoan
2019-01-11 8:58 ` [PATCH 2/2] spi: sh-msiof: Use DMA if possible Nguyen An Hoan
2019-01-11 9:09 ` Geert Uytterhoeven [this message]
2019-01-11 9:27 ` Hoan
2019-01-11 10:05 ` Geert Uytterhoeven
2019-01-18 8:19 ` Hoan
2019-01-11 9:01 ` [PATCH 1/2] spi: sh-msiof: fix *info pointer in request_dma() Geert Uytterhoeven
2019-01-11 10:15 ` Sergei Shtylyov
2019-01-11 13:26 ` Mark Brown
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