From patchwork Wed Aug 28 08:21:49 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephen Boyd X-Patchwork-Id: 11118175 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C93A2112C for ; Wed, 28 Aug 2019 08:22:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A05732189D for ; Wed, 28 Aug 2019 08:22:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="CsodN8Ty" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726605AbfH1IWI (ORCPT ); Wed, 28 Aug 2019 04:22:08 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:43161 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726321AbfH1IVz (ORCPT ); Wed, 28 Aug 2019 04:21:55 -0400 Received: by mail-pl1-f195.google.com with SMTP id 4so871117pld.10 for ; Wed, 28 Aug 2019 01:21:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=zBHpNvufe28nLemPiNmtcBO4lsWCA9oHO3YETBlFgi4=; b=CsodN8TyIXBUvJIf8wrH4ECCazW4cHFoHhyOesxNpaIdhZoxOUHWaSA10IQOlNTD0D KbfLc9iTL244E3wQojl7eL/NeLFhWUCi/ZHveyHaByH30l7mTy1SWPjz7Jq1OUr1w5cb 5+jMzeIpWl9EsbExUX8qKFs55sslZwFuXnIKI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=zBHpNvufe28nLemPiNmtcBO4lsWCA9oHO3YETBlFgi4=; b=cg5EYzsGoREaDxoX18ZaNryyCBSG2mLz+9YM/CJu6qqkXpZVvyWMpMxJWC5Ip4a5ds e6oU0g0wOrtlpBn6U+aoi1TM2eVQbnnGYsrrCl63TfmrUfTZcEbaDJrSk1HU6xA8PCPR Myd9ArfbcK2Ef+D3y+twUHUaHeE3T7rVSRG3+uDui69gSVpFAeT9iIaGAt+26kpZAcKN PiwbIn9G97tT7D8ChXITnbBQnnQ3EUP30oVO1WLUEdysZBP5XBg121TsIG5lRCyDMvUC wrRh5KKb+sN8HUYOABEZXz4uylJDkof6UR4cZTHi8FkPRUlPYq646tFJU+aUQPgvric7 qvZQ== X-Gm-Message-State: APjAAAV0gwDPQauz2O4GdBeWAl5s1lfw6A4rOEAvT460X/xBxBmLlm+1 aOKqYHAlbSJGd9dKbIQXphwf4Q== X-Google-Smtp-Source: APXvYqxNfuZcG+FCfxCwwXrymGrrC78fPo1dlzMiQr2RsEW1DtIZgFw5mh5ldb74v70RfnvZ/HcTuQ== X-Received: by 2002:a17:902:1024:: with SMTP id b33mr3126228pla.325.1566980514791; Wed, 28 Aug 2019 01:21:54 -0700 (PDT) Received: from smtp.gmail.com ([2620:15c:202:1:fa53:7765:582b:82b9]) by smtp.gmail.com with ESMTPSA id y10sm1296959pjp.27.2019.08.28.01.21.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Aug 2019 01:21:54 -0700 (PDT) From: Stephen Boyd To: Peter Huewe , Jarkko Sakkinen Cc: linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, Andrey Pronin , Duncan Laurie , Jason Gunthorpe , Arnd Bergmann , Greg Kroah-Hartman , Guenter Roeck , Alexander Steffen , Heiko Stuebner Subject: [PATCH v5 3/4] tpm: tpm_tis_spi: Introduce a flow control callback Date: Wed, 28 Aug 2019 01:21:49 -0700 Message-Id: <20190828082150.42194-4-swboyd@chromium.org> X-Mailer: git-send-email 2.23.0.187.g17f5b7556c-goog In-Reply-To: <20190828082150.42194-1-swboyd@chromium.org> References: <20190828082150.42194-1-swboyd@chromium.org> MIME-Version: 1.0 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Cr50 firmware has a different flow control protocol than the one used by this TPM PTP SPI driver. Introduce a flow control callback so we can override the standard sequence with the custom one that Cr50 uses. Cc: Andrey Pronin Cc: Duncan Laurie Cc: Jason Gunthorpe Cc: Arnd Bergmann Cc: Greg Kroah-Hartman Cc: Guenter Roeck Cc: Alexander Steffen Cc: Heiko Stuebner Signed-off-by: Stephen Boyd Reviewed-by: Jarkko Sakkinen --- drivers/char/tpm/tpm_tis_spi.c | 62 ++++++++++++++++++++++------------ 1 file changed, 41 insertions(+), 21 deletions(-) diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c index 19513e622053..b3ed85671dd8 100644 --- a/drivers/char/tpm/tpm_tis_spi.c +++ b/drivers/char/tpm/tpm_tis_spi.c @@ -42,6 +42,8 @@ struct tpm_tis_spi_phy { struct tpm_tis_data priv; struct spi_device *spi_device; + int (*flow_control)(struct tpm_tis_spi_phy *phy, + struct spi_transfer *xfer); u8 *iobuf; }; @@ -50,12 +52,46 @@ static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *da return container_of(data, struct tpm_tis_spi_phy, priv); } +/* + * TCG SPI flow control is documented in section 6.4 of the spec[1]. In short, + * keep trying to read from the device until MISO goes high indicating the + * wait state has ended. + * + * [1] https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/ + */ +static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy, + struct spi_transfer *spi_xfer) +{ + struct spi_message m; + int ret, i; + + if ((phy->iobuf[3] & 0x01) == 0) { + // handle SPI wait states + phy->iobuf[0] = 0; + + for (i = 0; i < TPM_RETRY; i++) { + spi_xfer->len = 1; + spi_message_init(&m); + spi_message_add_tail(spi_xfer, &m); + ret = spi_sync_locked(phy->spi_device, &m); + if (ret < 0) + return ret; + if (phy->iobuf[0] & 0x01) + break; + } + + if (i == TPM_RETRY) + return -ETIMEDOUT; + } + + return 0; +} + static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, u8 *in, const u8 *out) { struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data); int ret = 0; - int i; struct spi_message m; struct spi_transfer spi_xfer; u8 transfer_len; @@ -82,26 +118,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, if (ret < 0) goto exit; - if ((phy->iobuf[3] & 0x01) == 0) { - // handle SPI wait states - phy->iobuf[0] = 0; - - for (i = 0; i < TPM_RETRY; i++) { - spi_xfer.len = 1; - spi_message_init(&m); - spi_message_add_tail(&spi_xfer, &m); - ret = spi_sync_locked(phy->spi_device, &m); - if (ret < 0) - goto exit; - if (phy->iobuf[0] & 0x01) - break; - } - - if (i == TPM_RETRY) { - ret = -ETIMEDOUT; - goto exit; - } - } + ret = phy->flow_control(phy, &spi_xfer); + if (ret < 0) + goto exit; spi_xfer.cs_change = 0; spi_xfer.len = transfer_len; @@ -207,6 +226,7 @@ static int tpm_tis_spi_probe(struct spi_device *dev) phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); if (!phy->iobuf) return -ENOMEM; + phy->flow_control = tpm_tis_spi_flow_control; /* If the SPI device has an IRQ then use that */ if (dev->irq > 0)