From nobody Thu Apr 9 12:47:26 2026 Received: from mail-wr1-f44.google.com (mail-wr1-f44.google.com [209.85.221.44]) (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 F11C13A784F for ; Mon, 9 Mar 2026 11:40:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.44 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773056438; cv=none; b=GEqVu4SZwl1ETjsLp0dqF9oaSuMjY2pHsEA0ZlHQWfdNdDq4EeEsizKmbdAeld5GFPJHbKw2vWwJq23nXMaBNjfiXf2+6ZHRJlE1AIq1M/5emmC5CZE5v+BPebjnwkgTZDtLWR1DnYfALHPDqaHU5QIFKdp4KNiZqvDDmoVKZEE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773056438; c=relaxed/simple; bh=iawZxXCHV/teSW9TbByTZ0aCl2jCak1q3AZVPQS3+5c=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=AV3utJPWjKpsMx5UrWvA+7h5bYLvl0yqxqArXJBjXz1pvEUvXNfBQEUutVif1VxWkMZ0UjP/rPtLiqRPcXkrdjfKnq/DjvILJJwY5FcBQdTc3iSa3D5ElRNBUsjv6Vhpk3ARQaJ5dHG7jtd8UFy56ZLo2TxO9abi4A040CWLhjI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=KrgWMTOn; arc=none smtp.client-ip=209.85.221.44 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KrgWMTOn" Received: by mail-wr1-f44.google.com with SMTP id ffacd0b85a97d-439d8df7620so1943818f8f.0 for ; Mon, 09 Mar 2026 04:40:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1773056435; x=1773661235; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=SQ9F92hXIJmt/OqV8+0Y8qWB6C+g5fuewMC6KiuhW88=; b=KrgWMTOnsO8lwwizqhdDWJnLDXQpcAOenotW3cn2jOgnEozvbH9RJXGfwfAqWa3QTb pn5rxFO8y9KZwweEVkn9gdpfImgL2j01bwpsiggntdHMHXSs+RRorjigdz5N4XB/pZSz kjfWD4Zy1W6ovBcUW0eviSDjUO5xTIM+09HYdZtcTuN+OtHXXc+s+nJVNTXFymrekFhh 6RnRTQowA4YFgkb1nGtyD4iFukeYZysYlAwR24OIkSt4i2NTeCutHnfTW/UvEM1StOwg fC1XAUG40qTDWdaVt5DqzqvVlVD98jQ9bu46SeMIXBsygfInwkm1EiKApe0LdCtHs+Y/ tILw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773056435; x=1773661235; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-gg:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=SQ9F92hXIJmt/OqV8+0Y8qWB6C+g5fuewMC6KiuhW88=; b=OZ+u6evOpGE7j048SPUh+9S0KfB74Q2bdA8VnHx/nSH2ydzX+fIq3oZ9BRSIXvO71q 9v3w/sbW58mJI+6S5SpgFd0bGnccyhH5bQJfPKUgXpKu0PZ5DY5SGoYLN6hI1MZFFIdd 0TjzveWCIdIjgUGiZ9kvqOssMUjPXti4841YCkmaMn1NJ3+6uF1W5q7bbnkeAB0Q7H7W GpjloJK/iWDZATFiP3ricEwtbD/n5V9ad43eLy6BhdMzwJ5G36kF3llJ5jFTOqhQOgKt F+dgJYmGlJ+ilng5qv2YXJEe+wFYkDwqMH5Xp8A5qzMk8+lfJKSnPX9hcOSx7Rr15qOP KRCg== X-Forwarded-Encrypted: i=1; AJvYcCVizF9wdNin6HFJXiMH35lFAkQqT+gZw7WuUN5PI0iQTc+ssLtzr6YjEgx0UI53YHsB8+Ej7zG3+G8iyBM=@vger.kernel.org X-Gm-Message-State: AOJu0Yx7IWTO4YmUhYGQ/PT/XY/yE6SgMOfDi0KjWd+y+b8CyOaPvYpJ XxPrerlMfQ/LMg1IA64zVjoJIeQpg9Q3VYEW1W60Sd+f6ZgUSxWQId26 X-Gm-Gg: ATEYQzyBU6eeFdowNof0aNGAPz+b4QcL/5VQd4oYZvz0HMOHCYxqtr3HuihWYhlCUHk xJvEMT0I6uhbFWXDj90BAIQyQJq1zIDCtaiUGO2P+0XB3rm862xSNvlVYm51rWkiJQ41mnvHNpu CrXuWXd9J6JDBkI1xoHK6a2EpIHLgEs7evTVeL9s9pSM+Jg3CM6Xn8Tar/vpdrdmYkHObfaFIQS mLBtvAAk1Pnrhwv4fCEatwN1TbegBhh08QrF0LaQ5rd83JgvfTqdIOStMXEJEohSJBnFliVXOcE tfNacp0zB1WUgaPE2jB+0QhHWDPfNKkR7Gd8q+an2+0n8tde+HcdxlApwEO1i3H52kFrAB6R+S4 pOA+vhMVmqNPYNDTvChKusq3ujBAOuJTpp27DAsu062I1rKrqHq41Hik4Wvt/zrjQYWZQ5hJfae pZ7hcQBZQQuirkTs85X688eis7L8caUHyWnjXgzOWMKXZYrOFEdlYieUhGi4SaXgLg X-Received: by 2002:a05:6000:1886:b0:439:b541:a091 with SMTP id ffacd0b85a97d-439da8a2cd8mr18675754f8f.56.1773056435052; Mon, 09 Mar 2026 04:40:35 -0700 (PDT) Received: from ipedrosa-thinkpadx1carbongen12.rmtes.csb ([67.218.236.52]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-439dad8ec97sm28471699f8f.5.2026.03.09.04.40.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Mar 2026 04:40:34 -0700 (PDT) From: Iker Pedrosa Date: Mon, 09 Mar 2026 12:40:14 +0100 Subject: [PATCH v2 4/7] mmc: sdhci-of-k1: add comprehensive SDR tuning support Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260309-orangepi-sd-card-uhs-v2-4-5bb2b574df5d@gmail.com> References: <20260309-orangepi-sd-card-uhs-v2-0-5bb2b574df5d@gmail.com> In-Reply-To: <20260309-orangepi-sd-card-uhs-v2-0-5bb2b574df5d@gmail.com> To: Ulf Hansson , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Adrian Hunter , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Yixun Lan , Yixun Lan Cc: Michael Opdenacker , Javier Martinez Canillas , linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, linux-riscv@lists.infradead.org, spacemit@lists.linux.dev, linux-kernel@vger.kernel.org, Iker Pedrosa X-Mailer: b4 0.14.2 Implement software tuning algorithm to enable UHS-I SDR modes for SD card operation. This adds both TX and RX delay line tuning based on the SpacemiT K1 controller capabilities. Key features: - Conditional tuning: only tune when SD card is present and for high-speed modes (=E2=89=A5100MHz) - TX tuning: configure transmit delay line with default values (dline_reg=3D0, delaycode=3D127) to ensure optimal signal output timing - RX tuning: test full delay range (0-255) with window detection algorithm to find optimal receive timing - Retry mechanism: multiple fallback delays within optimal window for improved reliability - Complete register support: add delay line control and configuration register definitions for fine-grained timing control Signed-off-by: Iker Pedrosa --- drivers/mmc/host/sdhci-of-k1.c | 119 +++++++++++++++++++++++++++++++++++++= ++++ 1 file changed, 119 insertions(+) diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c index 79cb7c8d0b6d9c4206bf01721651c8efe8a173c9..d903851b9be0e1d21a2b30636f5= e63a52cad0dc2 100644 --- a/drivers/mmc/host/sdhci-of-k1.c +++ b/drivers/mmc/host/sdhci-of-k1.c @@ -84,6 +84,12 @@ #define SDHC_TX_DLINE_REG_MASK GENMASK(23, 16) =20 #define SPACEMIT_RX_DLINE_REG 9 +#define SPACEMIT_RX_TUNE_DELAY_MIN 0x0 +#define SPACEMIT_RX_TUNE_DELAY_MAX 0xFF +#define SPACEMIT_RX_TUNE_DELAY_STEP 0x1 + +#define SPACEMIT_TX_TUNING_DLINE_REG 0x00 +#define SPACEMIT_TX_TUNING_DELAYCODE 127 =20 struct spacemit_sdhci_host { struct clk *clk_core; @@ -251,6 +257,118 @@ static unsigned int spacemit_sdhci_clk_get_max_clock(= struct sdhci_host *host) return clk_get_rate(pltfm_host->clk); } =20 +static int spacemit_sdhci_execute_tuning(struct sdhci_host *host, u32 opco= de) +{ + int ret =3D 0; + int i; + bool pass_window[SPACEMIT_RX_TUNE_DELAY_MAX + 1] =3D {false}; + int pass_len =3D 0, pass_start =3D 0, max_pass_len =3D 0, max_pass_start = =3D 0; + u8 final_delay; + struct mmc_host *mmc =3D host->mmc; + struct mmc_ios ios =3D mmc->ios; + + /* + * Tuning is required for SDR50/SDR104, HS200/HS400 cards and + * if clock frequency is greater than 100MHz in these modes. + */ + if (host->clock < 100 * 1000 * 1000 || + !(ios.timing =3D=3D MMC_TIMING_MMC_HS200 || + ios.timing =3D=3D MMC_TIMING_UHS_SDR50 || + ios.timing =3D=3D MMC_TIMING_UHS_SDR104)) + return 0; + + if (!(mmc->caps2 & MMC_CAP2_NO_SD) && !mmc->ops->get_cd(mmc)) + return 0; + + if (mmc->caps2 & MMC_CAP2_NO_MMC) { + spacemit_sdhci_set_tx_dline_reg(host, SPACEMIT_TX_TUNING_DLINE_REG); + spacemit_sdhci_set_tx_delay(host, SPACEMIT_TX_TUNING_DELAYCODE); + spacemit_sdhci_tx_tuning_prepare(host); + + dev_dbg(mmc_dev(host->mmc), "TX tuning: dline_reg=3D%d, delaycode=3D%d\n= ", + SPACEMIT_TX_TUNING_DLINE_REG, SPACEMIT_TX_TUNING_DELAYCODE); + } + + spacemit_sdhci_prepare_tuning(host); + + for (i =3D SPACEMIT_RX_TUNE_DELAY_MIN; i <=3D SPACEMIT_RX_TUNE_DELAY_MAX; + i +=3D SPACEMIT_RX_TUNE_DELAY_STEP) { + spacemit_sdhci_set_rx_delay(host, i); + + ret =3D mmc_send_tuning(host->mmc, opcode, NULL); + pass_window[i] =3D (ret =3D=3D 0); + + dev_dbg(mmc_dev(host->mmc), "RX delay %d: %s\n", + i, pass_window[i] ? "pass" : "fail"); + } + + for (i =3D SPACEMIT_RX_TUNE_DELAY_MIN; i <=3D SPACEMIT_RX_TUNE_DELAY_MAX; + i +=3D SPACEMIT_RX_TUNE_DELAY_STEP) { + if (pass_window[i]) { + if (pass_len =3D=3D 0) + pass_start =3D i; + pass_len++; + } else { + if (pass_len > max_pass_len) { + max_pass_len =3D pass_len; + max_pass_start =3D pass_start; + } + pass_len =3D 0; + } + } + + if (pass_len > max_pass_len) { + max_pass_len =3D pass_len; + max_pass_start =3D pass_start; + } + + if (max_pass_len < 3) { + dev_err(mmc_dev(host->mmc), "Tuning failed: no stable window found\n"); + return -EIO; + } + + final_delay =3D max_pass_start + max_pass_len / 2; + spacemit_sdhci_set_rx_delay(host, final_delay); + ret =3D mmc_send_tuning(host->mmc, opcode, NULL); + if (ret) { + u8 retry_delays[] =3D { + max_pass_start + max_pass_len / 4, + max_pass_start + (3 * max_pass_len) / 4, + max_pass_start, + max_pass_start + max_pass_len - 1 + }; + int retry_count =3D ARRAY_SIZE(retry_delays); + + dev_warn(mmc_dev(mmc), "Primary delay %d failed, trying alternatives\n", + final_delay); + + for (i =3D 0; i < retry_count; i++) { + if (retry_delays[i] >=3D SPACEMIT_RX_TUNE_DELAY_MIN && + retry_delays[i] <=3D SPACEMIT_RX_TUNE_DELAY_MAX) { + spacemit_sdhci_set_rx_delay(host, retry_delays[i]); + ret =3D mmc_send_tuning(host->mmc, opcode, NULL); + if (!ret) { + final_delay =3D retry_delays[i]; + dev_info(mmc_dev(mmc), "Retry successful with delay %d\n", + final_delay); + break; + } + } + } + + if (ret) { + dev_err(mmc_dev(mmc), "All retry attempts failed\n"); + return -EIO; + } + } + + dev_dbg(mmc_dev(host->mmc), + "Tuning successful: window %d-%d, using delay %d\n", + max_pass_start, max_pass_start + max_pass_len - 1, final_delay); + + return 0; +} + static int spacemit_sdhci_pre_select_hs400(struct mmc_host *mmc) { struct sdhci_host *host =3D mmc_priv(mmc); @@ -344,6 +462,7 @@ static const struct sdhci_ops spacemit_sdhci_ops =3D { .set_clock =3D spacemit_sdhci_set_clock, .set_uhs_signaling =3D spacemit_sdhci_set_uhs_signaling, .voltage_switch =3D spacemit_sdhci_voltage_switch, + .platform_execute_tuning =3D spacemit_sdhci_execute_tuning, }; =20 static const struct sdhci_pltfm_data spacemit_sdhci_k1_pdata =3D { --=20 2.53.0