From patchwork Tue Apr 11 22:55:43 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 9676197 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 51DCA60231 for ; Tue, 11 Apr 2017 22:56:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3F1222851F for ; Tue, 11 Apr 2017 22:56:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3399C28589; Tue, 11 Apr 2017 22:56:20 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9703C2851F for ; Tue, 11 Apr 2017 22:56:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752547AbdDKW4S (ORCPT ); Tue, 11 Apr 2017 18:56:18 -0400 Received: from mail-pg0-f42.google.com ([74.125.83.42]:33962 "EHLO mail-pg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753109AbdDKW4P (ORCPT ); Tue, 11 Apr 2017 18:56:15 -0400 Received: by mail-pg0-f42.google.com with SMTP id 21so5262041pgg.1 for ; Tue, 11 Apr 2017 15:56:14 -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; bh=5kN1lK/LfevnXnyTtBN2c2ANaBwI19tKuZsbMv0n/ko=; b=XGNgscUWDK3BabBCa1apg6p/ljuacdxvKfvma8NaANRxf6Gcd3agcEdDao4wtYPsct IzH9UQ4ET9XY/8IsxStpcSe3OBFkiCK86lXbHO3n6MnR7SSzjnJCQmBFRbYweEQ8rHxD HXaqERg0fBuwOVXT2IyCDAiJRc5tpG33Xzvp8= 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; bh=5kN1lK/LfevnXnyTtBN2c2ANaBwI19tKuZsbMv0n/ko=; b=TpKEwyzQAbhFGok6/4OeoszDK9kgT49C8mrYg2jGnBZgo83h2fCokKF3E6+BOd1ss1 P2dkKxTkX1cGj2FRv34y6RCOWVanaOo5Hy1gFQt+eUL1d8cujkCArIWCdxSkvmTv0P7S HKhXOukDxI+c9ZkzLatZp4QzrAv4RXajQKXOLNYKkVJmRSaTJ2ideVXJSKm6FKzTMDxo 1GvdeM0eGpl99ml7sOJG3yemTamvnjVa516ocJVahYl4OJRhUGGpEYkbuv/Tbx3Upcpi WmqhlhGlbxJIhGaWa/RX64Os3TulbIP/lpXuTVPLQIMIjfvygkfIdl7sAECYbXliJ7EF Da1w== X-Gm-Message-State: AN3rC/4hKc+BTL8rVw4RkoqqTnIb0rm+pA1uNnPFd88H9AJMCaJZrK+psUrOEs7PJPGTjwuK X-Received: by 10.84.216.91 with SMTP id f27mr11639318plj.130.1491951374354; Tue, 11 Apr 2017 15:56:14 -0700 (PDT) Received: from tictac.mtv.corp.google.com ([172.22.65.76]) by smtp.gmail.com with ESMTPSA id 70sm12105135pfk.49.2017.04.11.15.56.12 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 11 Apr 2017 15:56:13 -0700 (PDT) From: Douglas Anderson To: Jaehoon Chung , Ulf Hansson Cc: briannorris@chromium.org, linux-rockchip@lists.infradead.org, Shawn Lin , Heiko Stuebner , kevin@archlinuxarm.org, amstan@chromium.org, xzy.xu@rock-chips.com, Douglas Anderson , stable@vger.kernel.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] mmc: dw_mmc: Don't allow Runtime PM for SDIO cards Date: Tue, 11 Apr 2017 15:55:43 -0700 Message-Id: <20170411225543.987-1-dianders@chromium.org> X-Mailer: git-send-email 2.12.2.715.g7642488e1d-goog Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP According to the SDIO standard interrupts are normally signalled in a very complicated way. They require the card clock to be running and require the controller to be paying close attention to the signals coming from the card. This simply can't happen with the clock stopped or with the controller in a low power mode. To that end, we'll disable runtime_pm when we detect that an SDIO card was inserted. This is much like with what we do with the special "SDMMC_CLKEN_LOW_PWR" bit that dw_mmc supports. NOTE: we specifically do this Runtime PM disabling at card init time rather than in the enable_sdio_irq() callback. This is _different_ than how SDHCI does it. Why do we do it differently? - Unlike SDHCI, dw_mmc uses the standard sdio_irq code in Linux (AKA dw_mmc doesn't set MMC_CAP2_SDIO_IRQ_NOTHREAD). - Because we use the standard sdio_irq code: - We see a constant stream of enable_sdio_irq(0) and enable_sdio_irq(1) calls. This is because the standard code disables interrupts while processing and re-enables them after. - While interrupts are disabled, there's technically a period where we could get runtime disabled while processing interrupts. - If we are runtime disabled while processing interrupts, we'll reset the controller at resume time (see dw_mci_runtime_resume), which seems like a terrible idea because we could possibly have another interrupt pending. To fix the above isues we'd want to put something in the standard sdio_irq code that makes sure to call pm_runtime get/put when interrupts are being actively being processed. That's possible to do, but it seems like a more complicated mechanism when we really just want the runtime pm disabled always for SDIO cards given that all the other bits needed to get Runtime PM vs. SDIO just aren't there. NOTE: at some point in time someone might come up with a fancy way to do SDIO interrupts and still allow (some) amount of runtime PM. Technically we could turn off the card clock if we used an alternate way of signaling SDIO interrupts (and out of band interrupt is one way to do this). We probably wouldn't actually want to fully runtime suspend in this case though--at least not with the current dw_mci_runtime_resume() which basically fully resets the controller at resume time. Fixes: e9ed8835e990 ("mmc: dw_mmc: add runtime PM callback") Cc: Reported-by: Brian Norris Signed-off-by: Douglas Anderson Acked-by: Jaehoon Chung Reviewed-by: Shawn Lin Tested-by: Brian Norris --- drivers/mmc/host/dw_mmc.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 249ded65192e..e45129f48174 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -1620,10 +1621,16 @@ static void dw_mci_init_card(struct mmc_host *mmc, struct mmc_card *card) if (card->type == MMC_TYPE_SDIO || card->type == MMC_TYPE_SD_COMBO) { - set_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags); + if (!test_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags)) { + pm_runtime_get_noresume(mmc->parent); + set_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags); + } clk_en_a = clk_en_a_old & ~clken_low_pwr; } else { - clear_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags); + if (test_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags)) { + pm_runtime_put_noidle(mmc->parent); + clear_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags); + } clk_en_a = clk_en_a_old | clken_low_pwr; }