From: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Ulf HANSSON <ulf.hansson@stericsson.com>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Lee Jones <lee.jones@linaro.org>
Subject: Re: [PATCH 4/4] mmc: mmci: Fix incorrect handling of HW flow control for SDIO
Date: Mon, 3 Oct 2011 09:31:14 +0200 [thread overview]
Message-ID: <4E8964C2.5000300@stericsson.com> (raw)
In-Reply-To: <20111001161248.GG11710@n2100.arm.linux.org.uk>
Hi Russel,
On 10/01/2011 06:12 PM, Russell King - ARM Linux wrote:
> Shouldn't this also re-enable the ST hardware flow control for non-SDIO
> cards?
I do not think that is needed. Hardware flow control is turned on per
default for all cards thanks to the .clkreg member of the variant struct:
mmci_set_clkreg():
clk |= variant->clkreg_enable;
where
static struct variant_data variant_ux500v2 = {
.clkreg_enable = MCI_ST_UX500_HWFCEN,
This means that HWFC will be on for all cards. This patch only disables
it for SDIO cards (thanks to the mmc_card_sdio()-check) during
problematic transfers (HW peculiarity), and then re-enables it again for
SDIO cards during "normal" transfers. So the HWFC state for non-SDIO
cards should not be touched I think.
Best Regards
Stefan Nilsson
WARNING: multiple messages have this Message-ID (diff)
From: stefan.xk.nilsson@stericsson.com (Stefan Nilsson XK)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 4/4] mmc: mmci: Fix incorrect handling of HW flow control for SDIO
Date: Mon, 3 Oct 2011 09:31:14 +0200 [thread overview]
Message-ID: <4E8964C2.5000300@stericsson.com> (raw)
In-Reply-To: <20111001161248.GG11710@n2100.arm.linux.org.uk>
Hi Russel,
On 10/01/2011 06:12 PM, Russell King - ARM Linux wrote:
> Shouldn't this also re-enable the ST hardware flow control for non-SDIO
> cards?
I do not think that is needed. Hardware flow control is turned on per
default for all cards thanks to the .clkreg member of the variant struct:
mmci_set_clkreg():
clk |= variant->clkreg_enable;
where
static struct variant_data variant_ux500v2 = {
.clkreg_enable = MCI_ST_UX500_HWFCEN,
This means that HWFC will be on for all cards. This patch only disables
it for SDIO cards (thanks to the mmc_card_sdio()-check) during
problematic transfers (HW peculiarity), and then re-enables it again for
SDIO cards during "normal" transfers. So the HWFC state for non-SDIO
cards should not be touched I think.
Best Regards
Stefan Nilsson
next prev parent reply other threads:[~2011-10-03 7:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-27 7:46 [PATCH 4/4] mmc: mmci: Fix incorrect handling of HW flow control for SDIO Ulf Hansson
2011-09-27 7:46 ` Ulf Hansson
2011-10-01 16:12 ` Russell King - ARM Linux
2011-10-01 16:12 ` Russell King - ARM Linux
2011-10-03 7:31 ` Stefan Nilsson XK [this message]
2011-10-03 7:31 ` Stefan Nilsson XK
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