From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 556C6C4332F for ; Mon, 28 Mar 2022 15:46:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239181AbiC1PsX (ORCPT ); Mon, 28 Mar 2022 11:48:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239085AbiC1PqK (ORCPT ); Mon, 28 Mar 2022 11:46:10 -0400 Received: from mail.baikalelectronics.ru (mail.baikalelectronics.com [87.245.175.226]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7648D4AE3B; Mon, 28 Mar 2022 08:44:18 -0700 (PDT) Received: from mail.baikalelectronics.ru (unknown [192.168.51.25]) by mail.baikalelectronics.ru (Postfix) with ESMTP id D57901E28D4; Thu, 24 Mar 2022 03:16:37 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.baikalelectronics.ru D57901E28D4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baikalelectronics.ru; s=mail; t=1648080997; bh=WwPZH0B/nbV8SPoRsnfa0nApSVFo28Gv/7atL+OBCV4=; h=From:To:CC:Subject:Date:In-Reply-To:References:From; b=G6fhluXK/HeWLEpvOSJmMgfNTLbDeIzc4qqbGv6vy2xkZyEj+/2Dffrr0FEDXYsKC PDEtpsoJuXO2GccFVQQA6nrGGy9T9X/gjABOxKX6r9O4gLkI74Kkfnuzn2AaX+HgoD ObNJ+FD5N/7B/iGGVHmue4voGN0WUpaM3dIZ/ihg= Received: from localhost (192.168.168.10) by mail (192.168.51.25) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Thu, 24 Mar 2022 03:16:37 +0300 From: Serge Semin To: Damien Le Moal , Hans de Goede , Jens Axboe CC: Serge Semin , Serge Semin , Alexey Malahov , Pavel Parkhomenko , Rob Herring , , , Subject: [PATCH 09/21] ata: libahci_platform: Introduce reset assertion/deassertion methods Date: Thu, 24 Mar 2022 03:16:16 +0300 Message-ID: <20220324001628.13028-10-Sergey.Semin@baikalelectronics.ru> In-Reply-To: <20220324001628.13028-1-Sergey.Semin@baikalelectronics.ru> References: <20220324001628.13028-1-Sergey.Semin@baikalelectronics.ru> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: MAIL.baikal.int (192.168.51.25) To mail (192.168.51.25) Precedence: bulk List-ID: X-Mailing-List: linux-ide@vger.kernel.org Currently the ACHI-platform library supports only the assert and deassert reset signals and ignores the platforms with self-deasserting reset lines. That prone to having the platforms with self-deasserting reset method misbehaviour when it comes to resuming from sleep state after the clocks have been fully disabled. For such cases the controller needs to be fully reset all over after the reference clocks are enabled and stable, otherwise the controller state machine might be in an undetermined state. The best solution would be to auto-detect which reset method is supported by the particular platform and use it implicitly in the framework of the ahci_platform_enable_resources()/ahci_platform_disable_resources() methods. Alas it can't be implemented due to the AHCI-platform library already supporting the shared reset control lines. As [1] says in such case we have to use only one of the next methods: + reset_control_assert()/reset_control_deassert(); + reset_control_reset()/reset_control_rearm(). If the driver had an exclusive control over the reset lines we could have been able to manipulate the lines with no much limitation and just used the combination of the methods above to cover all the possible reset-control cases. Since the shared reset control has already been advertised and couldn't be changed with no risk to breaking the platforms relying on it, we have no choice but to make the platform drivers to determine which reset methods the platform reset system supports. In order to implement both types of reset control support we suggest to introduce the new AHCI-platform flag: AHCI_PLATFORM_RST_TRIGGER, which when passed to the ahci_platform_get_resources() method together with the AHCI_PLATFORM_GET_RESETS flag will indicate that the reset lines are self-deasserting thus the reset_control_reset()/reset_control_rearm() will be used to control the reset state. Otherwise the reset_control_deassert()/reset_control_assert() methods will be utilized. [1] Documentation/driver-api/reset.rst Signed-off-by: Serge Semin --- drivers/ata/ahci.h | 1 + drivers/ata/libahci_platform.c | 47 ++++++++++++++++++++++++++++++---- include/linux/ahci_platform.h | 5 +++- 3 files changed, 47 insertions(+), 6 deletions(-) diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h index 1564c691094a..0b1d5c24cb8c 100644 --- a/drivers/ata/ahci.h +++ b/drivers/ata/ahci.h @@ -342,6 +342,7 @@ struct ahci_host_priv { bool got_runtime_pm; /* Did we do pm_runtime_get? */ unsigned int n_clks; struct clk_bulk_data *clks; /* Optional */ + unsigned int f_rsts; struct reset_control *rsts; /* Optional */ struct regulator **target_pwrs; /* Optional */ struct regulator *ahci_regulator;/* Optional */ diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c index 5998e735a813..febad33aa43c 100644 --- a/drivers/ata/libahci_platform.c +++ b/drivers/ata/libahci_platform.c @@ -150,6 +150,41 @@ void ahci_platform_disable_clks(struct ahci_host_priv *hpriv) } EXPORT_SYMBOL_GPL(ahci_platform_disable_clks); +/** + * ahci_platform_deassert_rsts - Deassert/trigger platform resets + * @hpriv: host private area to store config values + * + * This function desserts or triggers all the reset lanes found for the AHCI + * device. + * + * RETURNS: + * 0 on success otherwise a negative error code + */ +int ahci_platform_deassert_rsts(struct ahci_host_priv *hpriv) +{ + if (hpriv->f_rsts & AHCI_PLATFORM_RST_TRIGGER) + return reset_control_reset(hpriv->rsts); + + return reset_control_deassert(hpriv->rsts); +} +EXPORT_SYMBOL_GPL(ahci_platform_deassert_rsts); + +/** + * ahci_platform_assert_rsts - Assert/rearm platform resets + * @hpriv: host private area to store config values + * + * This function asserts or rearms (for self-deasserting resets) all the reset + * controls found for the AHCI device. + */ +void ahci_platform_assert_rsts(struct ahci_host_priv *hpriv) +{ + if (hpriv->f_rsts & AHCI_PLATFORM_RST_TRIGGER) + return (void)reset_control_rearm(hpriv->rsts); + + reset_control_assert(hpriv->rsts); +} +EXPORT_SYMBOL_GPL(ahci_platform_assert_rsts); + /** * ahci_platform_enable_regulators - Enable regulators * @hpriv: host private area to store config values @@ -247,18 +282,18 @@ int ahci_platform_enable_resources(struct ahci_host_priv *hpriv) if (rc) goto disable_regulator; - rc = reset_control_deassert(hpriv->rsts); + rc = ahci_platform_deassert_rsts(hpriv); if (rc) goto disable_clks; rc = ahci_platform_enable_phys(hpriv); if (rc) - goto disable_resets; + goto disable_rsts; return 0; -disable_resets: - reset_control_assert(hpriv->rsts); +disable_rsts: + ahci_platform_assert_rsts(hpriv); disable_clks: ahci_platform_disable_clks(hpriv); @@ -285,7 +320,7 @@ void ahci_platform_disable_resources(struct ahci_host_priv *hpriv) { ahci_platform_disable_phys(hpriv); - reset_control_assert(hpriv->rsts); + ahci_platform_assert_rsts(hpriv); ahci_platform_disable_clks(hpriv); @@ -468,6 +503,8 @@ struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev, rc = PTR_ERR(hpriv->rsts); goto err_out; } + + hpriv->f_rsts = flags & AHCI_PLATFORM_RST_TRIGGER; } /* diff --git a/include/linux/ahci_platform.h b/include/linux/ahci_platform.h index fd964e6a68d6..57d25d30a9fa 100644 --- a/include/linux/ahci_platform.h +++ b/include/linux/ahci_platform.h @@ -26,6 +26,8 @@ struct clk * ahci_platform_find_clk(struct ahci_host_priv *hpriv, const char *con_id); int ahci_platform_enable_clks(struct ahci_host_priv *hpriv); void ahci_platform_disable_clks(struct ahci_host_priv *hpriv); +int ahci_platform_deassert_rsts(struct ahci_host_priv *hpriv); +void ahci_platform_assert_rsts(struct ahci_host_priv *hpriv); int ahci_platform_enable_regulators(struct ahci_host_priv *hpriv); void ahci_platform_disable_regulators(struct ahci_host_priv *hpriv); int ahci_platform_enable_resources(struct ahci_host_priv *hpriv); @@ -44,6 +46,7 @@ int ahci_platform_resume_host(struct device *dev); int ahci_platform_suspend(struct device *dev); int ahci_platform_resume(struct device *dev); -#define AHCI_PLATFORM_GET_RESETS 0x01 +#define AHCI_PLATFORM_GET_RESETS BIT(0) +#define AHCI_PLATFORM_RST_TRIGGER BIT(1) #endif /* _AHCI_PLATFORM_H */ -- 2.35.1