From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755526AbcJMGDL (ORCPT ); Thu, 13 Oct 2016 02:03:11 -0400 Received: from mx0a-0016f401.pphosted.com ([67.231.148.174]:58751 "EHLO mx0b-0016f401.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755215AbcJMGDG (ORCPT ); Thu, 13 Oct 2016 02:03:06 -0400 Subject: Re: [PATCH 6/10] mmc: sdhci-xenon: Add Marvell Xenon SDHC core functionality To: Adrian Hunter , Gregory CLEMENT , Ulf Hansson , References:

<1b015f16-aa37-591c-3299-9431f6e82cce@intel.com> <4009a66b-1e09-0780-b7c1-128ff1401b5f@marvell.com> <7939a923-eb97-ca44-ac4c-f0a3cd4f45bc@intel.com> CC: Jason Cooper , Andrew Lunn , Sebastian Hesselbarth , Rob Herring , , Thomas Petazzoni , , "Jack(SH) Zhu" , Jimmy Xu , Jisheng Zhang , Nadav Haklai , Ryan Gao , Doug Jones , Shiwu Zhang , Victor Gu , "Wei(SOCP) Liu" , Wilson Ding , Xueping Liu , Hilbert Zhang , Liuliu Zhao , Peng Zhu , Yu Cao , Romain Perier , Yehuda Yitschak , Marcin Wojtas , Hanna Hawa , Kostya Porotchkin , From: Ziji Hu Message-ID: <6bed26dc-f4c1-7f0d-36b6-d7d5fcbf0da9@marvell.com> Date: Thu, 13 Oct 2016 13:38:18 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <7939a923-eb97-ca44-ac4c-f0a3cd4f45bc@intel.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-10-13_02:,, signatures=0 X-Proofpoint-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1610130092 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Adrian, On 2016/10/12 21:07, Adrian Hunter wrote: > On 12/10/16 14:58, Ziji Hu wrote: >> Hi Adrian, >> >> Thank you very much for your review. >> I will firstly fix the typo. >> >> On 2016/10/11 20:37, Adrian Hunter wrote: >>>> + >>>> +static int xenon_start_signal_voltage_switch(struct mmc_host *mmc, >>>> + struct mmc_ios *ios) >>>> +{ >>>> + struct sdhci_host *host = mmc_priv(mmc); >>>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); >>>> + struct sdhci_xenon_priv *priv = sdhci_pltfm_priv(pltfm_host); >>>> + >>>> + /* >>>> + * Before SD/SDIO set signal voltage, SD bus clock should be >>>> + * disabled. However, sdhci_set_clock will also disable the Internal >>>> + * clock in mmc_set_signal_voltage(). >>>> + * If Internal clock is disabled, the 3.3V/1.8V bit can not be updated. >>>> + * Thus here manually enable internal clock. >>>> + * >>>> + * After switch completes, it is unnecessary to disable internal clock, >>>> + * since keeping internal clock active obeys SD spec. >>>> + */ >>>> + enable_xenon_internal_clk(host); >>>> + >>>> + if (priv->card_candidate) { >>> >>> mmc_power_up() calls __mmc_set_signal_voltage() calls >>> host->ops->start_signal_voltage_switch so priv->card_candidate could be an >>> invalid reference to an old card. >>> >>> So that's not going to work if the card changes - not only for removable >>> cards but even for eMMC if init fails and retries. >>> >> As you point out, this piece of code have defects, even though it actually works on Marvell multiple platforms, unless eMMC card is removable. >> >> I can add a property to explicitly indicate eMMC type in DTS. >> Then card_candidate access can be removed here. >> Does it sounds more reasonable to you? > > Sure > >> >>>> + if (mmc_card_mmc(priv->card_candidate)) >>>> + return xenon_emmc_signal_voltage_switch(mmc, ios); >>> >>> So if all you need to know is whether it is a eMMC, why can't DT tell you? >>> >> I can add an eMMC type property in DTS, to remove the card_candidate access here. >> >>>> + } >>>> + >>>> + return sdhci_start_signal_voltage_switch(mmc, ios); >>>> +} >>>> + >>>> +/* >>>> + * After determining which slot is used for SDIO, >>>> + * some additional task is required. >>>> + */ >>>> +static void xenon_init_card(struct mmc_host *mmc, struct mmc_card *card) >>>> +{ >>>> + struct sdhci_host *host = mmc_priv(mmc); >>>> + u32 reg; >>>> + u8 slot_idx; >>>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); >>>> + struct sdhci_xenon_priv *priv = sdhci_pltfm_priv(pltfm_host); >>>> + >>>> + /* Link the card for delay adjustment */ >>>> + priv->card_candidate = card; >>> >>> You really need a better way to get the card. I suggest you take up the >>> issue with Ulf. One possibility is to have mmc core set host->card = card >>> much earlier. >>> >> Could you please tell me if any issue related to card_candidate still exists, after the card_candidate is removed from xenon_start_signal_voltage_switch() in above? >> It seems that when init_card is called, the structure card has already been updated and stable in MMC/SD/SDIO initialization sequence. >> May I keep it here? > > It works by accident rather than by design. We can do better. > Could you please tell me some details which are satisfied about card_candidate? I must admit that card_candidate in xenon_start_signal_voltage_switch() is imperfect. But card_candidate in init_card() and later in set_ios() work by design, rather than by accident. We did a lot of tests on several platforms. The structure mmc_card passed in here is a stable one. Thus in my very own opinion, it is safe and stable to use mmc_card here. card_candidate is used only in card initialization. It is not active in later transfers after initialization is done. It will always updated with mmc_card in next card initialization. >> >>>> + /* Set tuning functionality of this slot */ >>>> + xenon_slot_tuning_setup(host); >>>> + >>>> + slot_idx = priv->slot_idx; >>>> + if (!mmc_card_sdio(card)) { >>>> + /* Re-enable the Auto-CMD12 cap flag. */ >>>> + host->quirks |= SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12; >>>> + host->flags |= SDHCI_AUTO_CMD12; >>>> + >>>> + /* Clear SDIO Card Inserted indication */ >>>> + reg = sdhci_readl(host, SDHC_SYS_CFG_INFO); >>>> + reg &= ~(1 << (slot_idx + SLOT_TYPE_SDIO_SHIFT)); >>>> + sdhci_writel(host, reg, SDHC_SYS_CFG_INFO); >>>> + >>>> + if (mmc_card_mmc(card)) { >>>> + mmc->caps |= MMC_CAP_NONREMOVABLE; >>>> + if (!(host->quirks2 & SDHCI_QUIRK2_NO_1_8_V)) >>>> + mmc->caps |= MMC_CAP_1_8V_DDR; >>>> + /* >>>> + * Force to clear BUS_TEST to >>>> + * skip bus_test_pre and bus_test_post >>>> + */ >>>> + mmc->caps &= ~MMC_CAP_BUS_WIDTH_TEST; >>>> + mmc->caps2 |= MMC_CAP2_HC_ERASE_SZ | >>>> + MMC_CAP2_PACKED_CMD; >>>> + if (mmc->caps & MMC_CAP_8_BIT_DATA) >>>> + mmc->caps2 |= MMC_CAP2_HS400_1_8V; >>>> + } >>>> + } else { >>>> + /* >>>> + * Delete the Auto-CMD12 cap flag. >>>> + * Otherwise, when sending multi-block CMD53, >>>> + * Driver will set Transfer Mode Register to enable Auto CMD12. >>>> + * However, SDIO device cannot recognize CMD12. >>>> + * Thus SDHC will time-out for waiting for CMD12 response. >>>> + */ >>>> + host->quirks &= ~SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12; >>>> + host->flags &= ~SDHCI_AUTO_CMD12; >>> >>> sdhci_set_transfer_mode() won't enable auto-CMD12 for CMD53 anyway, so is >>> this needed? >>> >> In Xenon driver, Auto-CMD12 flag is set to enable full support to Auto-CMD feature, both Auto-CMD12 and Auto-CMD23. >> As a result, when Xenon SDHC slot can both support SD and SDIO, Auto-CMD12 is disabled when SDIO card is inserted, and renabled when SD is inserted. >> >> I recheck the sdhci code to set Auto-CMD bit in Transfer Mode register, in sdhci_set_transfer_mode(): >> if (mmc_op_multi(cmd->opcode) || data->blocks > 1) >> As you can see, as long as it is CMD18/CMD25 OR there are multiple data blocks, Auto-CMD field will be set. >> CMD53 doesn't have CMD23. Thus Auto-CMD12 is selected since Auto-CMD12 flag is set. >> Thus I have to clear Auto-CMD12 to avoid issuing Auto-CMD12 in SDIO transfer. > > > The code is: > > if (mmc_op_multi(cmd->opcode) || data->blocks > 1) { > mode = SDHCI_TRNS_BLK_CNT_EN | SDHCI_TRNS_MULTI; > /* > * If we are sending CMD23, CMD12 never gets sent > * on successful completion (so no Auto-CMD12). > */ > if (sdhci_auto_cmd12(host, cmd->mrq) && > (cmd->opcode != SD_IO_RW_EXTENDED)) > mode |= SDHCI_TRNS_AUTO_CMD12; > else if (cmd->mrq->sbc && (host->flags & SDHCI_AUTO_CMD23)) { > mode |= SDHCI_TRNS_AUTO_CMD23; > sdhci_writel(host, cmd->mrq->sbc->arg, SDHCI_ARGUMENT2); > } > } > > You can see the check for SD_IO_RW_EXTENDED which is CMD53. > Sorry. I didn't notice CMD53 check was added. I introduced this Auto-CMD12 hack since kernel 3.8. It seems that this check is not added in kernel 3.8. Thanks for the information. I will remove the Auto-CMD12 hack. >> >> I just meet a similar issue in RPMB. >> When Auto-CMD12 flag is set, eMMC RPMB access will trigger Auto-CMD12, since CMD25 is in use. >> It will cause RPMB access failed. > > Can you explain more about the RPMB issue. Doesn't it use CMD23, so CMD12 > wouldn't be used - auto or manually. > RPMB go through the MMC ioctl routine. Unlike normal data transfer, MMC ioctl for RPMB explicitly issues CMD23. When CMD25 is issued, there is neither data->sbc nor Auto-CMD23. As a result, sdhci driver will automatically enable Auto-CMD12 for RPMB CMD25 if Auto-CMD12 flag is set. >> >> One possible solution is to drop Auto-CMD12 support and use Auto-CMD23 only, in Xenon driver. >> May I know you opinion, please? > > I don't use auto-CMD12 because I don't know if it provides any benefit and > sdhci does not seem to have implemented Auto CMD12 Error Recovery, although > I have never looked at it closely. > Actually, Auto-CMD23 is always used on our Xenon. Auto-CMD12 is not used at all. But since this driver is a general one for all Marvell products, Auto-CMD12 is also supported in case that Auto-CMD23 is not available.