From owner-svn-src-all@freebsd.org Sat Dec 7 17:24:08 2019 Return-Path: Delivered-To: svn-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 648EB1D78B2; Sat, 7 Dec 2019 17:24:08 +0000 (UTC) (envelope-from ian@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 47Vbsh22Dxz410Z; Sat, 7 Dec 2019 17:24:08 +0000 (UTC) (envelope-from ian@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 28ED31D24A; Sat, 7 Dec 2019 17:24:08 +0000 (UTC) (envelope-from ian@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id xB7HO8dT022620; Sat, 7 Dec 2019 17:24:08 GMT (envelope-from ian@FreeBSD.org) Received: (from ian@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id xB7HO7J8022618; Sat, 7 Dec 2019 17:24:07 GMT (envelope-from ian@FreeBSD.org) Message-Id: <201912071724.xB7HO7J8022618@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: ian set sender to ian@FreeBSD.org using -f From: Ian Lepore Date: Sat, 7 Dec 2019 17:24:07 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r355494 - stable/12/sys/dev/iicbus X-SVN-Group: stable-12 X-SVN-Commit-Author: ian X-SVN-Commit-Paths: stable/12/sys/dev/iicbus X-SVN-Commit-Revision: 355494 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 07 Dec 2019 17:24:08 -0000 Author: ian Date: Sat Dec 7 17:24:07 2019 New Revision: 355494 URL: https://svnweb.freebsd.org/changeset/base/355494 Log: MFC r352338: Create a mechanism for encoding a system errno into the IIC_Exxxxx space. Errors are communicated between the i2c controller layer and upper layers (iicbus and slave device drivers) using a set of IIC_Exxxxxx constants which effectively define a private number space separate from (and having values that conflict with) the system errno number space. Sometimes it is necessary to report a plain old system error (especially EINTR) from the controller or bus layer and have that value make it back across the syscall interface intact. I initially considered replicating a few "crucial" errno values with similar names and new numbers, e.g., IIC_EINTR, IIC_ERESTART, etc. It seemed like that had the potential to grow over time until many of the errno names were duplicated into the IIC_Exxxxx space. So instead, this defines a mechanism to "encode" an errno into the IIC_Exxxx space by setting the high bit and putting the errno into the lower-order bits; a new errno2iic() function does this. The existing iic2errno() recognizes the encoded values and extracts the original errno out of the encoded value. An interesting wrinkle occurs with the pseudo-error values such as ERESTART -- they aleady have the high bit set, and turning it off would be the wrong thing to do. Instead, iic2errno() recognizes that lots of high bits are on (i.e., it's a negative number near to zero) and just returns that value as-is. Thus, existing drivers continue to work without needing any changes, and there is now a way to return errno values from the lower layers. The first use of that is in iicbus_poll() which does mtx_sleep() with the PCATCH flag, and needs to return the errno from that up the call chain. Differential Revision: https://reviews.freebsd.org/D20975 Modified: stable/12/sys/dev/iicbus/iiconf.c stable/12/sys/dev/iicbus/iiconf.h Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/dev/iicbus/iiconf.c ============================================================================== --- stable/12/sys/dev/iicbus/iiconf.c Sat Dec 7 17:19:36 2019 (r355493) +++ stable/12/sys/dev/iicbus/iiconf.c Sat Dec 7 17:24:07 2019 (r355494) @@ -42,6 +42,18 @@ __FBSDID("$FreeBSD$"); #include "iicbus_if.h" /* + * Encode a system errno value into the IIC_Exxxxx space by setting the + * IIC_ERRNO marker bit, so that iic2errno() can turn it back into a plain + * system errno value later. This lets controller- and bus-layer code get + * important system errno values (such as EINTR/ERESTART) back to the caller. + */ +int +errno2iic(int errno) +{ + return ((errno == 0) ? 0 : errno | IIC_ERRNO); +} + +/* * Translate IIC_Exxxxx status values to vaguely-equivelent errno values. */ int @@ -59,7 +71,22 @@ iic2errno(int iic_status) case IIC_ENOTSUPP: return (EOPNOTSUPP); case IIC_ENOADDR: return (EADDRNOTAVAIL); case IIC_ERESOURCE: return (ENOMEM); - default: return (EIO); + default: + /* + * If the high bit is set, that means it's a system errno value + * that was encoded into the IIC_Exxxxxx space by setting the + * IIC_ERRNO marker bit. If lots of high-order bits are set, + * then it's one of the negative pseudo-errors such as ERESTART + * and we return it as-is. Otherwise it's a plain "small + * positive integer" errno, so just remove the IIC_ERRNO marker + * bit. If it's some unknown number without the high bit set, + * there isn't much we can do except call it an I/O error. + */ + if ((iic_status & IIC_ERRNO) == 0) + return (EIO); + if ((iic_status & 0xFFFF0000) != 0) + return (iic_status); + return (iic_status & ~IIC_ERRNO); } } @@ -97,7 +124,7 @@ iicbus_poll(struct iicbus_softc *sc, int how) return (IIC_EBUSBSY); } - return (error); + return (errno2iic(error)); } /* Modified: stable/12/sys/dev/iicbus/iiconf.h ============================================================================== --- stable/12/sys/dev/iicbus/iiconf.h Sat Dec 7 17:19:36 2019 (r355493) +++ stable/12/sys/dev/iicbus/iiconf.h Sat Dec 7 17:24:07 2019 (r355494) @@ -96,12 +96,14 @@ #define IIC_ENOTSUPP 0x8 /* request not supported */ #define IIC_ENOADDR 0x9 /* no address assigned to the interface */ #define IIC_ERESOURCE 0xa /* resources (memory, whatever) unavailable */ +#define IIC_ERRNO __INT_MIN /* marker bit: errno is in low-order bits */ /* * Note that all iicbus functions return IIC_Exxxxx status values, * except iic2errno() (obviously) and iicbus_started() (returns bool). */ extern int iic2errno(int); +extern int errno2iic(int); extern int iicbus_request_bus(device_t, device_t, int); extern int iicbus_release_bus(device_t, device_t); extern device_t iicbus_alloc_bus(device_t);