From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f177.google.com (mail-pf1-f177.google.com [209.85.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 069A83FC9 for ; Sat, 4 Sep 2021 10:38:22 +0000 (UTC) Received: by mail-pf1-f177.google.com with SMTP id v123so1524101pfb.11 for ; Sat, 04 Sep 2021 03:38:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=R1xW5dhI5MdMWEzd4wBz2g9T6oS/nscW3i7iz8B4JF4=; b=HpqLoJEgYUbhqc2bFgHHAv1ULMAbKdNHpo6SpdPmUUBATbKEnlMs+yaSVQLt5DT2/5 EKu12Uyy3/y0qrd0KJQe5fC/7LKo8J53JUWXbas8GyI0Gq0vD71CkG8yeXd3r/3GJg9G OLzVdSZpzBi0AmeDbvyGaYQzza5Xu+2Sh49Kal9UsyC2hPl/nkIY+lufeNkijKROKe6k 1Hv2HjfkVX3Iu5uk9cglsBlUNfcjsMtBHvvByrF0+uW3jylO7g9taH/CTug9d+uViNqh k7DfAbNYwH6IVH0Z3TcFhWreAhcNYHeJB8XOoc+jxDy48rHI3l90aoYGdffDWVEeYXRJ ez/A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=R1xW5dhI5MdMWEzd4wBz2g9T6oS/nscW3i7iz8B4JF4=; b=A6EJlXTpzJuxmaWCGXByD5nXVcuXzlzLVI4THXv2aBbUJjQQzMgFca2MgaCDGry+tk IEGQIwC5cS5D4AhRzL4t90quYF/qBsLOOUJzg4m41Ej134tj3y5titstZ8P/0+liM5DZ PBkBA2Rj7b4jR12YHbKd6wKoXsySprMLlQYXoyEaer0EEBOW37Yso+Gba+0+UuyAqX6o Quo2e8aR7wSk37QNN0laDEpfn6nZJ+AFkfcRx4OCJ2+210tYXmNXYaC5P3z+eAPygfy/ oCXMBVvPXwxDYdkOFKIsclHCIj0FOt5kYQ1UiihCw077qCQQR+t80dPk7yeb1Fj8pBKS Rp/w== X-Gm-Message-State: AOAM5331jvvONojRCCXHq8TfFlPwVTF767nbMAX0YTBaUFzVk0jA3mqj EpURZz5CjpZmmqjS7PII5ojU24Zm0al3Zw== X-Google-Smtp-Source: ABdhPJw4py10hDMDA93ust0NUPG+eBLUsaxvPqJbHkdz6EfAp7jHVCWxkNnhkfvO5kQK5Yd60zVsjA== X-Received: by 2002:a63:111f:: with SMTP id g31mr3147053pgl.80.1630751901812; Sat, 04 Sep 2021 03:38:21 -0700 (PDT) Received: from [172.16.100.12] ([1.235.44.150]) by smtp.gmail.com with ESMTPSA id 66sm2027792pfx.29.2021.09.04.03.38.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 04 Sep 2021 03:38:20 -0700 (PDT) Subject: Re: [PATCH] sunxi: mmc: A20: Fix MMC optimisation To: Andre Przywara , Jagan Teki , Tom Rini Cc: Jernej Skrabec , Samuel Holland , u-boot@lists.denx.de, linux-sunxi@lists.linux.dev References: <20210903154916.5264-1-andre.przywara@arm.com> From: Jaehoon Chung Message-ID: <9459f678-17ca-19dc-e5e5-b1e2e1b61a31@gmail.com> Date: Sat, 4 Sep 2021 19:38:17 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 Precedence: bulk X-Mailing-List: linux-sunxi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20210903154916.5264-1-andre.przywara@arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Andre Przywara wrote on 9/4/21 12:49 AM: > Some SoCs (as seen on A20) seem to misreport the MMC FIFO level if the > FIFO is completely full: the level size reads as zero, but the FIFO_FULL > bit is set. We won't do a single iteration of the read loop in this > case, so will be stuck forever. > > Check for this situation and use a safe minimal FIFO size instead when > we hit this case. > > This fixes MMC boot on A20 devices after the MMC FIFO optimisation > (9faae5457f52). > > Signed-off-by: Andre Przywara Reviewed-by: Jaehoon Chung Best Regards, Jaehoon Chung > --- > drivers/mmc/sunxi_mmc.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/mmc/sunxi_mmc.c b/drivers/mmc/sunxi_mmc.c > index 178b8cf106..aaab0cf866 100644 > --- a/drivers/mmc/sunxi_mmc.c > +++ b/drivers/mmc/sunxi_mmc.c > @@ -349,10 +349,14 @@ static int mmc_trans_data_by_cpu(struct sunxi_mmc_priv *priv, struct mmc *mmc, > * register without checking the status register after every > * read. That saves half of the costly MMIO reads, effectively > * doubling the read performance. > + * Some SoCs (A20) report a level of 0 if the FIFO is > + * completely full (value masked out?). Use a safe minimal > + * FIFO size in this case. > */ > - for (in_fifo = SUNXI_MMC_STATUS_FIFO_LEVEL(status); > - in_fifo > 0; > - in_fifo--) > + in_fifo = SUNXI_MMC_STATUS_FIFO_LEVEL(status); > + if (in_fifo == 0 && (status & SUNXI_MMC_STATUS_FIFO_FULL)) > + in_fifo = 32; > + for (; in_fifo > 0; in_fifo--) > buff[i++] = readl_relaxed(&priv->reg->fifo); > dmb(); > }