From: Ulf Hansson <ulf.hansson@linaro.org>
To: Chen-Yu Tsai <wens@csie.org>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>,
Hans de Goede <hdegoede@redhat.com>,
linux-mmc <linux-mmc@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-sunxi@googlegroups.com
Subject: Re: [PATCH RFC 03/15] mmc: sunxi: Block signal voltage switching (CMD11)
Date: Fri, 29 Jan 2016 11:42:13 +0100 [thread overview]
Message-ID: <CAPDyKFrG8cXChSRuAx-a++iNHUHU_GuUApDhxfPSJZb1Oo1fsg@mail.gmail.com> (raw)
In-Reply-To: <1453354002-28366-4-git-send-email-wens@csie.org>
On 21 January 2016 at 06:26, Chen-Yu Tsai <wens@csie.org> wrote:
> Allwinner's mmc controller supports signal voltage switching. This is
> supported in code in Allwinner's kernel. However, publicly available
> boards all tie it to a fixed 3.0/3.3V regulator, with options to tie
> it to 1.8V for eMMC on some.
>
> Since Allwinner's kernel is an ancient 3.4, it is hard to say whether
> adapting it's code to a modern mainline kernel would work. Block signal
> voltage switching until someone has proper hardware to implement and
> test this.
>
> This only affects SD UHS-1 modes, as eMMC switches the voltage directly
> without any signaling.
>
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
> drivers/mmc/host/sunxi-mmc.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
> index 790f01662b4e..0495ae7da6d6 100644
> --- a/drivers/mmc/host/sunxi-mmc.c
> +++ b/drivers/mmc/host/sunxi-mmc.c
> @@ -816,6 +816,20 @@ static void sunxi_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
> }
> }
>
> + /*
> + * TODO Support signal voltage switching
> + *
> + * Compared to Allwinner's kernel, recent updates in the mmc core
> + * mean this should be as easy as setting the flags in cmd_val and
> + * imask, and waiting for it to finish. However no boards support
> + * this so this cannot be tested. Block it for now.
> + */
> + if (cmd->opcode == SD_SWITCH_VOLTAGE) {
> + mrq->cmd->error = -EPERM;
> + mmc_request_done(mmc, mrq);
> + return;
> + }
Unless some of the MMC_CAP_UHS* mode is set, this command shouldn't be sent.
So, if you *really* want to protect from this, I think it's better to
clear these caps in the ->probe() function, after mmc_of_parse() has
been called.
> +
> if (cmd->opcode == MMC_GO_IDLE_STATE) {
> cmd_val |= SDXC_SEND_INIT_SEQUENCE;
> imask |= SDXC_COMMAND_DONE;
> --
> 2.7.0.rc3
>
Kind regards
Uffe
next prev parent reply other threads:[~2016-01-29 10:42 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-21 5:26 [PATCH RFC 00/15] mmc: sunxi: Support vqmmc regulator and eMMC DDR modes Chen-Yu Tsai
2016-01-21 5:26 ` [PATCH RFC 01/15] mmc: sunxi: Document host init sequence Chen-Yu Tsai
2016-01-29 11:39 ` Ulf Hansson
2016-01-21 5:26 ` [PATCH RFC 02/15] mmc: sunxi: Return error on mmc_regulator_set_ocr() fail in .set_ios op Chen-Yu Tsai
2016-01-29 11:40 ` Ulf Hansson
2016-01-21 5:26 ` [PATCH RFC 03/15] mmc: sunxi: Block signal voltage switching (CMD11) Chen-Yu Tsai
2016-01-29 10:42 ` Ulf Hansson [this message]
2016-01-29 14:44 ` Chen-Yu Tsai
2016-01-21 5:26 ` [PATCH RFC 04/15] mmc: sunxi: Support vqmmc regulator Chen-Yu Tsai
2016-01-29 11:40 ` Ulf Hansson
2016-01-21 5:26 ` [PATCH RFC 05/15] mmc: sunxi: Support MMC_DDR52 timing modes Chen-Yu Tsai
2016-01-21 11:14 ` Hans de Goede
2016-01-21 11:55 ` Chen-Yu Tsai
2016-01-21 12:26 ` Hans de Goede
2016-01-21 5:26 ` [PATCH RFC 06/15] mmc: sunxi: Support 8 bit eMMC DDR transfer modes Chen-Yu Tsai
2016-01-21 5:26 ` [PATCH RFC 07/15] mmc: sunxi: Enable eMMC HS-DDR (MMC_CAP_1_8V_DDR) support Chen-Yu Tsai
2016-01-21 5:26 ` [PATCH RFC 08/15] ARM: dts: sun6i: Add mmc3 pins for 8 bit emmc Chen-Yu Tsai
2016-01-22 20:31 ` Maxime Ripard
2016-01-23 11:04 ` Chen-Yu Tsai
2016-01-24 16:54 ` Maxime Ripard
2016-01-21 5:26 ` [PATCH RFC 09/15] ARM: dts: sun6i: sina31s: Switch to mmc3 for onboard eMMC Chen-Yu Tsai
2016-01-21 11:16 ` Hans de Goede
2016-01-21 12:23 ` Chen-Yu Tsai
2016-01-21 12:25 ` Hans de Goede
2016-01-21 12:28 ` Chen-Yu Tsai
2016-01-21 12:38 ` Hans de Goede
2016-01-22 20:39 ` Maxime Ripard
2016-01-23 4:21 ` Chen-Yu Tsai
2016-01-24 16:56 ` Maxime Ripard
2016-01-21 5:26 ` [PATCH RFC 10/15] ARM: dts: sun8i: Include SDC2_RST pin in mmc2_8bit_pins Chen-Yu Tsai
2016-01-24 16:58 ` Maxime Ripard
2016-01-21 5:26 ` [PATCH RFC 11/15] ARM: dts: sun8i: sina33: Enable hardware reset and HS-DDR for eMMC Chen-Yu Tsai
2016-01-22 20:42 ` Maxime Ripard
2016-01-21 5:26 ` [PATCH RFC 12/15] ARM: dts: sun9i: Use sun9i specific mmc compatible Chen-Yu Tsai
2016-01-22 20:44 ` Maxime Ripard
2016-01-23 10:50 ` Chen-Yu Tsai
2016-01-21 5:26 ` [PATCH RFC 13/15] ARM: dts: sun9i: Include SDC2_RST pin in mmc2_8bit_pins Chen-Yu Tsai
2016-01-24 16:58 ` Maxime Ripard
2016-01-21 5:26 ` [PATCH RFC 14/15] ARM: dts: sun9i: a80-optimus: Enable hardware reset and HS-DDR for eMMC Chen-Yu Tsai
2016-01-24 16:59 ` Maxime Ripard
2016-01-21 5:26 ` [PATCH RFC 15/15] ARM: dts: sun9i: cubieboard4: " Chen-Yu Tsai
2016-01-24 16:59 ` Maxime Ripard
2016-01-21 11:19 ` [PATCH RFC 00/15] mmc: sunxi: Support vqmmc regulator and eMMC DDR modes Hans de Goede
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