From nobody Fri Dec 19 19:15:51 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CF3312973A2; Tue, 15 Apr 2025 15:37:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744731437; cv=none; b=F1inNoF/DPXBKqVxeILZIJCLFnxvWm3WUs2APGFK434d12hzJqMGCFiJ5tHDhGGCVWmexgN7h2RZpK2D0upUT4zdTcUWxHPiRDqn/wU1kW7SvdC87qLMrXdMJCZ6KKNgSZHsoDtiqdr0dn3XMhjt9OYXBCt58utSmv6kvFGZlqs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744731437; c=relaxed/simple; bh=iLhQrLWil25q6mOdTJw9OuNJ8sG/2mmYC9fMfHYOxvM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=WrxWDVg6ap0A6NMymJhM2hOQ7kNRngkHSCagZOmT10RfxMYqnWABeqGSicaEvcRnadUUk808Pqbi73yo4uDKW5SfHt6N7QiybcBhRpiJ6E/LT71QpAYhP2gZr9fSLpTSICGUz+zLqauy/UfaZ2LLM41IlzXEUE2s2VK1VEboJkM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lvE2uZVv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="lvE2uZVv" Received: by smtp.kernel.org (Postfix) with ESMTPS id 6C5C7C4CEF3; Tue, 15 Apr 2025 15:37:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744731437; bh=iLhQrLWil25q6mOdTJw9OuNJ8sG/2mmYC9fMfHYOxvM=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=lvE2uZVvO+1OD/IRYzyhzUtgUpbpJg0fN00+skg3iFQYSsoO1hnnBwuvnWxyvWWcD uZzh5YFc+a4ZFo/wpYHH+IFhPI2w9udSmKPvfYpJpnzzXSvYCK6sYeKCtmmx5VVxmJ e/Qi19A4DARCrGoXYkg6ZTikbNZBiFF2If2Su57/RgiKAK+xLh1T4J+ZRdxKTUpVOi T9KXwbvsj4XSJbr7q40Mjfsixs2/qyqL2gAojajM7Tk+4NScuVzyhrBjTqVNaJ9RuY 3OBe5Eme/wDmy0rCyDBWHaPDlxdPNV+zrNN9CIPlk+ykMKnP0TURN1xFlm7YCiQ7t9 B7WpOUrEOI23Q== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C1DDC369AB; Tue, 15 Apr 2025 15:37:17 +0000 (UTC) From: Sven Peter via B4 Relay Date: Tue, 15 Apr 2025 15:36:58 +0000 Subject: [PATCH v2 4/6] i2c: pasemi: Improve error recovery 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: <20250415-pasemi-fixes-v2-4-c543bf53151a@svenpeter.dev> References: <20250415-pasemi-fixes-v2-0-c543bf53151a@svenpeter.dev> In-Reply-To: <20250415-pasemi-fixes-v2-0-c543bf53151a@svenpeter.dev> To: Janne Grunau , Alyssa Rosenzweig , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Naveen N Rao , Andi Shyti , Neal Gompa , Hector Martin Cc: linuxppc-dev@lists.ozlabs.org, asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Sven Peter X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=4795; i=sven@svenpeter.dev; h=from:subject:message-id; bh=UdXQ8SUtLivYr558egJosJKmHk91VYvtGnZh/V57dEs=; b=owGbwMvMwCHmIlirolUq95LxtFoSQ/q/Wo13a1P715ycGSTHyJd7p1dg2YusT38uru8S/HfoW 4udw9lfHaUsDGIcDLJiiizb99ubPnn4RnDppkvvYeawMoEMYeDiFICJ+NYz/HdNckyT5XKt4GsS MeSS/31mp7N65u8gs9C8i406n1JjOBn+cDUKp69mDp+WPaHu2f6rqzh4Tj052h0e43FXwmtpzT9 dbgA= X-Developer-Key: i=sven@svenpeter.dev; a=openpgp; fpr=A1E3E34A2B3C820DBC4955E5993B08092F131F93 X-Endpoint-Received: by B4 Relay for sven@svenpeter.dev/default with auth_id=167 X-Original-From: Sven Peter Reply-To: sven@svenpeter.dev From: Hector Martin The hardware (supposedly) has a 25ms timeout for clock stretching and the driver uses 100ms which should be plenty. The error reocvery itself is however lacking. Add handling for all the missing error condition, and better recovery in pasemi_smb_clear(). Also move the timeout to a #define since it's used in multiple places now. Signed-off-by: Hector Martin [sven: adjusted commit message after splitting the commit into two] Signed-off-by: Sven Peter Reviewed-by: Alyssa Rosenzweig --- drivers/i2c/busses/i2c-pasemi-core.c | 75 +++++++++++++++++++++++++++++++-= ---- 1 file changed, 65 insertions(+), 10 deletions(-) diff --git a/drivers/i2c/busses/i2c-pasemi-core.c b/drivers/i2c/busses/i2c-= pasemi-core.c index 9b611dbdfef23e78a4ea75ac0311938d52b6ba96..2f31f039bedfd7f78d6572fe925= 125b1a6d0724b 100644 --- a/drivers/i2c/busses/i2c-pasemi-core.c +++ b/drivers/i2c/busses/i2c-pasemi-core.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -52,6 +53,12 @@ #define CTL_UJM BIT(8) #define CTL_CLK_M GENMASK(7, 0) =20 +/* + * The hardware (supposedly) has a 25ms timeout for clock stretching, thus + * use 100ms here which should be plenty. + */ +#define TRANSFER_TIMEOUT_MS 100 + static inline void reg_write(struct pasemi_smbus *smbus, int reg, int val) { dev_dbg(smbus->dev, "smbus write reg %x val %08x\n", reg, val); @@ -80,24 +87,44 @@ static void pasemi_reset(struct pasemi_smbus *smbus) reinit_completion(&smbus->irq_completion); } =20 -static void pasemi_smb_clear(struct pasemi_smbus *smbus) +static int pasemi_smb_clear(struct pasemi_smbus *smbus) { unsigned int status; + int ret; =20 - status =3D reg_read(smbus, REG_SMSTA); + /* First wait for the bus to go idle */ + ret =3D readx_poll_timeout(ioread32, smbus->ioaddr + REG_SMSTA, + status, !(status & (SMSTA_XIP | SMSTA_JAM)), + USEC_PER_MSEC, USEC_PER_MSEC * TRANSFER_TIMEOUT_MS); + + if (ret < 0) { + dev_err(smbus->dev, "Bus is still stuck (status 0x%08x)\n", status); + return -EIO; + } + + /* If any badness happened or there is data in the FIFOs, reset the FIFOs= */ + if ((status & (SMSTA_MRNE | SMSTA_JMD | SMSTA_MTO | SMSTA_TOM | SMSTA_MTN= | SMSTA_MTA)) || + !(status & SMSTA_MTE)) + pasemi_reset(smbus); + + /* Clear the flags */ reg_write(smbus, REG_SMSTA, status); + + return 0; } =20 static int pasemi_smb_waitready(struct pasemi_smbus *smbus) { - int timeout =3D 100; + int timeout =3D TRANSFER_TIMEOUT_MS; int ret; unsigned int status; =20 if (smbus->use_irq) { reinit_completion(&smbus->irq_completion); - reg_write(smbus, REG_IMASK, SMSTA_XEN | SMSTA_MTN); - ret =3D wait_for_completion_timeout(&smbus->irq_completion, msecs_to_jif= fies(100)); + /* XEN should be set when a transaction terminates, whether due to error= or not */ + reg_write(smbus, REG_IMASK, SMSTA_XEN); + ret =3D wait_for_completion_timeout(&smbus->irq_completion, + msecs_to_jiffies(timeout)); reg_write(smbus, REG_IMASK, 0); status =3D reg_read(smbus, REG_SMSTA); =20 @@ -123,9 +150,35 @@ static int pasemi_smb_waitready(struct pasemi_smbus *s= mbus) } } =20 + /* Controller timeout? */ + if (status & SMSTA_TOM) { + dev_warn(smbus->dev, "Controller timeout, status 0x%08x\n", status); + return -EIO; + } + + /* Peripheral timeout? */ + if (status & SMSTA_MTO) { + dev_warn(smbus->dev, "Peripheral timeout, status 0x%08x\n", status); + return -ETIME; + } + + /* Still stuck in a transaction? */ + if (status & SMSTA_XIP) { + dev_warn(smbus->dev, "Bus stuck, status 0x%08x\n", status); + return -EIO; + } + + /* Arbitration loss? */ + if (status & SMSTA_MTA) { + dev_warn(smbus->dev, "Arbitration loss, status 0x%08x\n", status); + return -EBUSY; + } + /* Got NACK? */ - if (status & SMSTA_MTN) + if (status & SMSTA_MTN) { + dev_warn(smbus->dev, "NACK, status 0x%08x\n", status); return -ENXIO; + } =20 /* Clear XEN */ reg_write(smbus, REG_SMSTA, SMSTA_XEN); @@ -187,9 +240,9 @@ static int pasemi_i2c_xfer(struct i2c_adapter *adapter, struct pasemi_smbus *smbus =3D adapter->algo_data; int ret, i; =20 - pasemi_smb_clear(smbus); - - ret =3D 0; + ret =3D pasemi_smb_clear(smbus); + if (ret) + return ret; =20 for (i =3D 0; i < num && !ret; i++) ret =3D pasemi_i2c_xfer_msg(adapter, &msgs[i], (i =3D=3D (num - 1))); @@ -210,7 +263,9 @@ static int pasemi_smb_xfer(struct i2c_adapter *adapter, addr <<=3D 1; read_flag =3D read_write =3D=3D I2C_SMBUS_READ; =20 - pasemi_smb_clear(smbus); + err =3D pasemi_smb_clear(smbus); + if (err) + return err; =20 switch (size) { case I2C_SMBUS_QUICK: --=20 2.34.1