From patchwork Mon Apr 27 14:53:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sakari Ailus X-Patchwork-Id: 210037 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7092BC54FCB for ; Mon, 27 Apr 2020 14:54:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E3FE206D9 for ; Mon, 27 Apr 2020 14:54:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728024AbgD0Oyv (ORCPT ); Mon, 27 Apr 2020 10:54:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38148 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1727115AbgD0Oyv (ORCPT ); Mon, 27 Apr 2020 10:54:51 -0400 X-Greylist: delayed 174 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 27 Apr 2020 07:54:50 PDT Received: from hillosipuli.retiisi.org.uk (hillosipuli.retiisi.org.uk [IPv6:2a01:4f9:c010:4572::81:2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0A1EC0610D5; Mon, 27 Apr 2020 07:54:50 -0700 (PDT) Received: from lanttu.localdomain (lanttu.retiisi.org.uk [IPv6:2a01:4f9:c010:4572::c1:2]) by hillosipuli.retiisi.org.uk (Postfix) with ESMTP id 0542A634C8B; Mon, 27 Apr 2020 17:53:58 +0300 (EEST) From: Sakari Ailus To: Petr Mladek Cc: Andy Shevchenko , linux-media@vger.kernel.org, Dave Stevenson , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, hverkuil@xs4all.nl, laurent.pinchart@ideasonboard.com, mchehab@kernel.org, Sergey Senozhatsky , Steven Rostedt , Joe Perches , Jani Nikula Subject: [RESEND PATCH v3 1/1] lib/vsprintf: Add support for printing V4L2 and DRM fourccs Date: Mon, 27 Apr 2020 17:53:03 +0300 Message-Id: <20200427145303.29943-1-sakari.ailus@linux.intel.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Add a printk modifier %p4cc (for pixel format) for printing V4L2 and DRM pixel formats denoted by fourccs. The fourcc encoding is the same for both so the same implementation can be used. Suggested-by: Mauro Carvalho Chehab Signed-off-by: Sakari Ailus --- since v2: - Add comments to explain why things are being done - Print characters under 32 (space) as hexadecimals in parenthesis. - Do not print spaces in the fourcc codes. - Make use of a loop over the fourcc characters instead of put_unaligned_le32(). This is necessary to omit spaces in the output. - Use DRM style format instead of V4L2. This provides the precise code as a numerical value as well as explicit endianness information. - Added WARN_ON_ONCE() sanity checks. Comments on these are welcome; I'd expect them mostly be covered by the tests. - Added tests for %p4cc in lib/test_printf.c Documentation/core-api/printk-formats.rst | 12 ++++ lib/test_printf.c | 17 +++++ lib/vsprintf.c | 86 +++++++++++++++++++++++ 3 files changed, 115 insertions(+) diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index 8ebe46b1af39..7aa0451e06fb 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -545,6 +545,18 @@ For printing netdev_features_t. Passed by reference. +V4L2 and DRM FourCC code (pixel format) +--------------------------------------- + +:: + + %p4cc + +Print a FourCC code used by V4L2 or DRM, including format endianness and +its numerical value as hexadecimal. + +Passed by reference. + Thanks ====== diff --git a/lib/test_printf.c b/lib/test_printf.c index 2d9f520d2f27..a14754086707 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -624,6 +624,22 @@ static void __init fwnode_pointer(void) software_node_unregister_nodes(softnodes); } +static void __init fourcc_pointer(void) +{ + struct { + u32 code; + char *str; + } const try[] = { + { 0x20104646, "FF(10) little-endian (0x20104646)", }, + { 0xa0104646, "FF(10) big-endian (0xa0104646)", }, + { 0x10111213, "(13)(12)(11)(10) little-endian (0x10111213)", }, + }; + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(try); i++) + test(try[i].str, "%p4cc", &try[i].code); +} + static void __init errptr(void) { @@ -668,6 +684,7 @@ test_pointer(void) flags(); errptr(); fwnode_pointer(); + fourcc_pointer(); } static void __init selftest(void) diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 7c488a1ce318..02e7906619c0 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1721,6 +1721,89 @@ char *netdev_bits(char *buf, char *end, const void *addr, return special_hex_number(buf, end, num, size); } +static noinline_for_stack +char *fourcc_string(char *buf, char *end, const u32 *__fourcc, + struct printf_spec spec, const char *fmt) +{ +#define FOURCC_HEX_CHAR_STR "(xx)" +#define FOURCC_BIG_ENDIAN_STR " big-endian" +#define FOURCC_LITTLE_ENDIAN_STR " little-endian" +#define FOURCC_HEX_NUMBER " (0x01234567)" +#define FOURCC_STRING_MAX \ + FOURCC_HEX_CHAR_STR FOURCC_HEX_CHAR_STR FOURCC_HEX_CHAR_STR \ + FOURCC_HEX_CHAR_STR FOURCC_LITTLE_ENDIAN_STR FOURCC_HEX_NUMBER + struct printf_spec my_spec = { + .type = FORMAT_TYPE_UINT, + .field_width = 2, + .flags = SMALL, + .base = 16, + .precision = -1, + }; + char __s[sizeof(FOURCC_STRING_MAX)]; + char *s = __s; + unsigned int i; + /* + * The 31st bit defines the endianness of the data, so save its printing + * for later. + */ + u32 fourcc = *__fourcc & ~BIT(31); + int ret; + + if (check_pointer(&buf, end, __fourcc, spec)) + return buf; + + if (fmt[1] != 'c' || fmt[2] != 'c') + return error_string(buf, end, "(%p4?)", spec); + + for (i = 0; i < sizeof(fourcc); i++, fourcc >>= 8) { + unsigned char c = fourcc; + + /* Weed out spaces */ + if (c == ' ') + continue; + + /* Print non-control characters as-is */ + if (c > ' ') { + *s = c; + s++; + continue; + } + + if (WARN_ON_ONCE(sizeof(__s) < + (s - __s) + sizeof(FOURCC_HEX_CHAR_STR))) + break; + + *s = '('; + s++; + s = number(s, s + 2, c, my_spec); + *s = ')'; + s++; + } + + ret = strscpy(s, *__fourcc & BIT(31) ? FOURCC_BIG_ENDIAN_STR + : FOURCC_LITTLE_ENDIAN_STR, + sizeof(__s) - (s - __s)); + if (!WARN_ON_ONCE(ret < 0)) + s += ret; + + if (!WARN_ON_ONCE(sizeof(__s) < + (s - __s) + sizeof(FOURCC_HEX_NUMBER))) { + *s = ' '; + s++; + *s = '('; + s++; + /* subtract parentheses and the space from the size */ + special_hex_number(s, s + sizeof(FOURCC_HEX_NUMBER) - 3, + *__fourcc, sizeof(u32)); + s += sizeof(u32) * 2 + 2 /* 0x */; + *s = ')'; + s++; + *s = '\0'; + } + + return string(buf, end, __s, spec); +} + static noinline_for_stack char *address_val(char *buf, char *end, const void *addr, struct printf_spec spec, const char *fmt) @@ -2131,6 +2214,7 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode, * correctness of the format string and va_list arguments. * - 'K' For a kernel pointer that should be hidden from unprivileged users * - 'NF' For a netdev_features_t + * - '4cc' V4L2 or DRM FourCC code, with endianness and raw numerical value. * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with * a certain separator (' ' by default): * C colon @@ -2223,6 +2307,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, return restricted_pointer(buf, end, ptr, spec); case 'N': return netdev_bits(buf, end, ptr, spec, fmt); + case '4': + return fourcc_string(buf, end, ptr, spec, fmt); case 'a': return address_val(buf, end, ptr, spec, fmt); case 'd':