Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Kevin Hilman <khilman@baylibre.com>
To:     Neil Armstrong <narmstrong@baylibre.com>, ulf.hansson@linaro.org
Cc:     linux-amlogic@lists.infradead.org, linux-mmc@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Neil Armstrong <narmstrong@baylibre.com>,
        Art Nikpal <art@khadas.com>,
        Christian Hewitt <christianshewitt@gmail.com>
Subject: Re: [PATCH] mmc: meson-gx: limit segments to 1 when dram-access-quirk is needed
In-Reply-To: <20200608084458.32014-1-narmstrong@baylibre.com>
References: <20200608084458.32014-1-narmstrong@baylibre.com>
Date:   Tue, 09 Jun 2020 07:54:20 -0700
Message-ID: <7hmu5cguhv.fsf@baylibre.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Neil Armstrong <narmstrong@baylibre.com> writes:

> The actual max_segs computation leads to failure while using the broadcom
> sdio brcmfmac/bcmsdh driver, since the driver tries to make usage of scatter
> gather.
>
> But with the dram-access-quirk we use a 1,5K SRAM bounce buffer, and the
> max_segs current value of 3 leads to max transfers to 4,5k, which doesn't work.
>
> This patch sets max_segs to 1 to better describe the hardware limitation,
> and fix the SDIO functionnality with the brcmfmac/bcmsdh driver on Amlogic
> G12A/G12B SoCs on boards like SEI510 or Khadas VIM3.
>
> Reported-by: Art Nikpal <art@khadas.com>
> Reported-by: Christian Hewitt <christianshewitt@gmail.com>
> Fixes: acdc8e71d9bb ("mmc: meson-gx: add dram-access-quirk")
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

Reviewed-by: Kevin Hilman <khilman@baylibre.com>