From patchwork Tue Feb 8 10:45:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Lucas De Marchi X-Patchwork-Id: 12738448 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 53081C433F5 for ; Tue, 8 Feb 2022 10:45:47 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3049210E6D2; Tue, 8 Feb 2022 10:45:18 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id 51DED10E224; Tue, 8 Feb 2022 10:45:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1644317112; x=1675853112; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=gqZNDevZLqM/RC37vfn+L0AvGvvPx+wqt3xJH2xPIQE=; b=cdiV7DfOa9ABEDadC1Qs05d2Klc/FiJ8R/6BBmarjqghK2kddCl7HLyy EYW53NpTNgmubBnpWxmGfeyfJSDvxV287ib4L237zR4jQXwSCCDtE3Qkw 9mKS0b9beUTU3V+lKs17gYaDDXypw9yE9fDXz6u1qZXnVH65uvD8HEJcj 9UfktVx+RrYj8HBJ2qlZLoXGnwiHFnHut+xsA5AUyGJM9trPEqMKgTyiT uQUhINXucdWQnB67DSLFYL1vtxxZmJOnox081ldsyPuXZVBfwkavIkZFi UsBArK3+qOgMZmhNM0S8a2QZBWkQY98U8z7QW1jIobno8cXNZ2Gafw/2o Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10251"; a="249130468" X-IronPort-AV: E=Sophos;i="5.88,352,1635231600"; d="scan'208";a="249130468" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2022 02:45:10 -0800 X-IronPort-AV: E=Sophos;i="5.88,352,1635231600"; d="scan'208";a="700804111" Received: from lucas-s2600cw.jf.intel.com ([10.165.21.202]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2022 02:45:09 -0800 From: Lucas De Marchi To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: [PATCH v2 02/18] iosys-map: Add a few more helpers Date: Tue, 8 Feb 2022 02:45:08 -0800 Message-Id: <20220208104524.2516209-3-lucas.demarchi@intel.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220208104524.2516209-1-lucas.demarchi@intel.com> References: <20220208104524.2516209-1-lucas.demarchi@intel.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Matthew Brost , =?utf-8?q?Thomas_Hellstr=C3=B6m?= , Lucas De Marchi , linux-kernel@vger.kernel.org, Daniele Ceraolo Spurio , Thomas Zimmermann , Mauro Carvalho Chehab , =?utf-8?q?Christian_K=C3=B6nig?= , John Harrison Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" First the simplest ones: - iosys_map_memset(): when abstracting system and I/O memory, just like the memcpy() use case, memset() also has dedicated functions to be called for using IO memory. - iosys_map_memcpy_from(): we may need to copy data from I/O memory, not only to. In certain situations it's useful to be able to read or write to an offset that is calculated by having the memory layout given by a struct declaration. Usually we are going to read/write a u8, u16, u32 or u64. As a pre-requisite for the implementation, add iosys_map_memcpy_from() to be the equivalent of iosys_map_memcpy_to(), but in the other direction. Then add 2 pairs of macros: - iosys_map_rd() / iosys_map_wr() - iosys_map_rd_field() / iosys_map_wr_field() The first pair takes the C-type and offset to read/write. The second pair uses a struct describing the layout of the mapping in order to calculate the offset and size being read/written. We could use readb, readw, readl, readq and the write* counterparts, however due to alignment issues this may not work on all architectures. If alignment needs to be checked to call the right function, it's not possible to decide at compile-time which function to call: so just leave the decision to the memcpy function that will do exactly that. Finally, in order to use the above macros with a map derived from another, add another initializer: IOSYS_MAP_INIT_OFFSET(). v2: - Rework IOSYS_MAP_INIT_OFFSET() so it doesn't rely on aliasing rules within the union - Add offset to both iosys_map_rd_field() and iosys_map_wr_field() to allow the struct itself to be at an offset from the mapping - Add documentation to iosys_map_rd_field() with example and expected memory layout Cc: Sumit Semwal Cc: Christian König Cc: Thomas Zimmermann Cc: Mauro Carvalho Chehab Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Lucas De Marchi Reviewed-by: Matt Atwood Reviewed-by: Mauro Carvalho Chehab --- include/linux/iosys-map.h | 202 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 202 insertions(+) diff --git a/include/linux/iosys-map.h b/include/linux/iosys-map.h index edd730b1e899..c6b223534b21 100644 --- a/include/linux/iosys-map.h +++ b/include/linux/iosys-map.h @@ -6,6 +6,7 @@ #ifndef __IOSYS_MAP_H__ #define __IOSYS_MAP_H__ +#include #include #include @@ -120,6 +121,45 @@ struct iosys_map { .is_iomem = false, \ } +/** + * IOSYS_MAP_INIT_OFFSET - Initializes struct iosys_map from another iosys_map + * @map_: The dma-buf mapping structure to copy from + * @offset_: Offset to add to the other mapping + * + * Initializes a new iosys_map struct based on another passed as argument. It + * does a shallow copy of the struct so it's possible to update the back storage + * without changing where the original map points to. It is the equivalent of + * doing: + * + * .. code-block:: c + * + * iosys_map map = other_map; + * iosys_map_incr(&map, &offset); + * + * Example usage: + * + * .. code-block:: c + * + * void foo(struct device *dev, struct iosys_map *base_map) + * { + * ... + * struct iosys_map map = IOSYS_MAP_INIT_OFFSET(base_map, FIELD_OFFSET); + * ... + * } + * + * The advantage of using the initializer over just increasing the offset with + * iosys_map_incr() like above is that the new map will always point to the + * right place of the buffer during its scope. It reduces the risk of updating + * the wrong part of the buffer and having no compiler warning about that. If + * the assignment to IOSYS_MAP_INIT_OFFSET() is forgotten, the compiler can warn + * about the use of uninitialized variable. + */ +#define IOSYS_MAP_INIT_OFFSET(map_, offset_) ({ \ + struct iosys_map copy = *map_; \ + iosys_map_incr(©, offset_); \ + copy; \ +}) + /** * iosys_map_set_vaddr - Sets a iosys mapping structure to an address in system memory * @map: The iosys_map structure @@ -239,6 +279,26 @@ static inline void iosys_map_memcpy_to(struct iosys_map *dst, size_t dst_offset, memcpy(dst->vaddr + dst_offset, src, len); } +/** + * iosys_map_memcpy_from - Memcpy from iosys_map into system memory + * @dst: Destination in system memory + * @src: The iosys_map structure + * @src_offset: The offset from which to copy + * @len: The number of byte in src + * + * Copies data from a iosys_map with an offset. The dest buffer is in + * system memory. Depending on the mapping location, the helper picks the + * correct method of accessing the memory. + */ +static inline void iosys_map_memcpy_from(void *dst, const struct iosys_map *src, + size_t src_offset, size_t len) +{ + if (src->is_iomem) + memcpy_fromio(dst, src->vaddr_iomem + src_offset, len); + else + memcpy(dst, src->vaddr + src_offset, len); +} + /** * iosys_map_incr - Increments the address stored in a iosys mapping * @map: The iosys_map structure @@ -255,4 +315,146 @@ static inline void iosys_map_incr(struct iosys_map *map, size_t incr) map->vaddr += incr; } +/** + * iosys_map_memset - Memset iosys_map + * @dst: The iosys_map structure + * @offset: Offset from dst where to start setting value + * @value: The value to set + * @len: The number of bytes to set in dst + * + * Set value in iosys_map. Depending on the buffer's location, the helper + * picks the correct method of accessing the memory. + */ +static inline void iosys_map_memset(struct iosys_map *dst, size_t offset, + int value, size_t len) +{ + if (dst->is_iomem) + memset_io(dst->vaddr_iomem + offset, value, len); + else + memset(dst->vaddr + offset, value, len); +} + +/** + * iosys_map_rd - Read a C-type value from the iosys_map + * + * @map__: The iosys_map structure + * @offset__: The offset from which to read + * @type__: Type of the value being read + * + * Read a C type value from iosys_map, handling possible un-aligned accesses to + * the mapping. + * + * Returns: + * The value read from the mapping. + */ +#define iosys_map_rd(map__, offset__, type__) ({ \ + type__ val; \ + iosys_map_memcpy_from(&val, map__, offset__, sizeof(val)); \ + val; \ +}) + +/** + * iosys_map_wr - Write a C-type value to the iosys_map + * + * @map__: The iosys_map structure + * @offset__: The offset from the mapping to write to + * @type__: Type of the value being written + * @val__: Value to write + * + * Write a C-type value to the iosys_map, handling possible un-aligned accesses + * to the mapping. + */ +#define iosys_map_wr(map__, offset__, type__, val__) ({ \ + type__ val = (val__); \ + iosys_map_memcpy_to(map__, offset__, &val, sizeof(val)); \ +}) + +/** + * iosys_map_rd_field - Read a member from a struct in the iosys_map + * + * @map__: The iosys_map structure + * @struct_offset__: Offset from the beggining of the map, where the struct + * is located + * @struct_type__: The struct describing the layout of the mapping + * @field__: Member of the struct to read + * + * Read a value from iosys_map considering its layout is described by a C struct + * starting at @struct_offset__. The field offset and size is calculated and its + * value read handling possible un-aligned memory accesses. For example: suppose + * there is a @struct foo defined as below and the value ``foo.field2.inner2`` + * needs to be read from the iosys_map: + * + * .. code-block:: c + * + * struct foo { + * int field1; + * struct { + * int inner1; + * int inner2; + * } field2; + * int field3; + * } __packed; + * + * This is the expected memory layout of a buffer using iosys_map_rd_field(): + * + * +------------------------------+--------------------------+ + * | Address | Content | + * +==============================+==========================+ + * | buffer + 0000 | start of mmapped buffer | + * | | pointed by iosys_map | + * +------------------------------+--------------------------+ + * | ... | ... | + * +------------------------------+--------------------------+ + * | buffer + ``struct_offset__`` | start of ``struct foo`` | + * +------------------------------+--------------------------+ + * | ... | ... | + * +------------------------------+--------------------------+ + * | buffer + wwww | ``foo.field2.inner2`` | + * +------------------------------+--------------------------+ + * | ... | ... | + * +------------------------------+--------------------------+ + * | buffer + yyyy | end of ``struct foo`` | + * +------------------------------+--------------------------+ + * | ... | ... | + * +------------------------------+--------------------------+ + * | buffer + zzzz | end of mmaped buffer | + * +------------------------------+--------------------------+ + * + * Values automatically calculated by this macro or not needed are denoted by + * wwww, yyyy and zzzz. This is the code to read that value: + * + * .. code-block:: c + * + * x = iosys_map_rd_field(&map, offset, struct foo, field2.inner2); + * + * Returns: + * The value read from the mapping. + */ +#define iosys_map_rd_field(map__, struct_offset__, struct_type__, field__) ({ \ + struct_type__ *s; \ + iosys_map_rd(map__, struct_offset__ + offsetof(struct_type__, field__), \ + typeof(s->field__)); \ +}) + +/** + * iosys_map_wr_field - Write to a member of a struct in the iosys_map + * + * @map__: The iosys_map structure + * @struct_offset__: Offset from the beggining of the map, where the struct + * is located + * @struct_type__: The struct describing the layout of the mapping + * @field__: Member of the struct to read + * @val__: Value to write + * + * Write a value to the iosys_map considering its layout is described by a C struct + * starting at @struct_offset__. The field offset and size is calculated and the + * @val__ is written handling possible un-aligned memory accesses. Refer to + * iosys_map_rd_field() for expected usage and memory layout. + */ +#define iosys_map_wr_field(map__, struct_offset__, struct_type__, field__, val__) ({ \ + struct_type__ *s; \ + iosys_map_wr(map__, struct_offset__ + offsetof(struct_type__, field__), \ + typeof(s->field__), val__); \ +}) + #endif /* __IOSYS_MAP_H__ */