245 lines
11 KiB
C
245 lines
11 KiB
C
/* ----> DO NOT REMOVE THE FOLLOWING NOTICE <----
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Copyright (c) 2014-2015 Datalight, Inc.
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All Rights Reserved Worldwide.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; use version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but "AS-IS," WITHOUT ANY WARRANTY; without even the implied warranty
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of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/* Businesses and individuals that for commercial or other reasons cannot
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comply with the terms of the GPLv2 license may obtain a commercial license
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before incorporating Reliance Edge into proprietary software for
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distribution in any form. Visit http://www.datalight.com/reliance-edge for
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more information.
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*/
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/** @file
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@brief Macros to encapsulate MISRA C:2012 deviations in OS-specific code.
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*/
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#ifndef REDOSDEVIATIONS_H
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#define REDOSDEVIATIONS_H
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#if REDCONF_OUTPUT == 1
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/* Needed for PRINT_ASSERT() and OUTPUT_CHARACTER().
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*/
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#include <stdio.h>
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#endif
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#if (REDCONF_ASSERTS == 1) && (REDCONF_OUTPUT == 1)
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/** Print a formatted message for an assertion.
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Usages of this macro deviate from MISRA C:2012 Rule 21.6 (required). Using
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printf() is the most convenient way to output this information; and the risk
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of "unspecified, undefined and implementation-defined" behavior causing
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problems (as cited in the rationale for the rule) is small. The driver does
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not depend on this string being outputted correctly. Furthermore, use of
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printf() disappears when either asserts or output are disabled.
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As Rule 21.6 is required, a separate deviation record is required.
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*/
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#define PRINT_ASSERT(file, line) \
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printf("Assertion failed in \"%s\" at line %u\n\r", ((file) == NULL) ? "" : (file), (unsigned)(line))
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#endif
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/** Cast a value to unsigned long.
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Usages of this macro deviate from MISRA C:2012 Directive 4.6. This macro is
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used in two places to cast a uint64_t value (used by the block device
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abstraction for sector numbers) to unsigned long, since third-party code
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which is not under the control of this project uses unsigned long for sector
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numbers. The cast is guaranteed to not lose any information, since when the
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disk is opened the sector count is verified to be less than or equal to an
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unsigned long value. The text of the directive mentions that "it might be
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desirable not to apply this guideline when interfacing with ... code outside
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the project's control", which describes the situation for this deviation.
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As Directive 4.6 is advisory, a deviation record is not required. This
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notice is the only record of the deviation.
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*/
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#define CAST_ULONG(ull) ((unsigned long)(ull))
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/** Cast a const-qualified pointer to a pointer which is *not* const-qualified.
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Usages of this macro deviate from MISRA C:2012 Rule 11.8. This macro is
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used in exactly one place in order to cope with a poorly designed
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third-party interface. Reliance Edge, at every level of the stack, uses
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const-qualified pointers for buffers used in write operations, since the
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data is read from the buffer, and the buffer does not need to be modified
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(consistent with Rule 8.13). One of the third-party block device interfaces
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that Reliance Edge interfaces with does not follow this convention: it uses
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an unqualified pointer for the buffer parameter of its sector write
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function. This forces the need for the cast to avoid warnings. The
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implementation of the sector write function is provided by the user, so it
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is to be hoped that the buffer is not actually modified.
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As Rule 11.8 is required, a separate deviation record is required.
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*/
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#define CAST_AWAY_CONST(type, ptr) ((type *)(ptr))
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/** Allocate zero-initialized (cleared) memory.
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All usages of this macro deviate from MISRA C:2012 Directive 4.12 (required)
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and Rule 21.3 (required). In the context of the single place it is actually
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used, this macro also deviates from Rule 22.1 (required).
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This macro is used in the FreeRTOS block device code in order to allocate a
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RAM disk, when that implementation of the block device is selected. The
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primary rationale for all these deviations is that a) the RAM disk cannot be
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allocated statically (since the volume information is stored in a
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structure), and b) the RAM disk is primarily intended as a temporary testing
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tool for users who want to try out Reliance Edge before the real storage
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media is available. In most real systems, Reliance Edge is used with
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non-volatile storage like SD/MMC or eMMC, not with RAM disks.
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Rule 22.1 states that all resources which are allocated must also be
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explicitly freed. The RAM disk is allocated and never freed, deviating from
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that rule. This is done because the data in the RAM disk is emulating a
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non-volatile storage medium, and thus needs to persist even after the block
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device is closed, to allow the file system to be ormatted and then mounted,
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or unmounted and remounted in the course of a test. Thus the memory will
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remain allocated until the target device is rebooted. This is assumed to be
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acceptable for the primary purpose of the RAM disk, which is preliminary
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testing.
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As Directive 4.12, Rule 21.3, and Rule 22.1 are all required, separate
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deviation records are required.
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*/
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#define ALLOCATE_CLEARED_MEMORY(nelem, elsize) calloc(nelem, elsize)
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#if REDCONF_OUTPUT == 1
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/** Output a character to a serial port or other display device.
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Usages of this macro deviate from MISRA C:2012 Rule 21.6 (required).
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FreeRTOS does not include a standard method of printing characters, so
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putchar() is the most convenient and portable way to accomplish the task.
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The risk of "unspecified, undefined and implementation-defined" behavior
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causing problems (as cited in the rationale for the rule) is small. The
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driver does not depend on the character being outputted correctly.
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Furthermore, use of putchar() disappears when output is disabled.
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As Rule 21.6 is required, a separate deviation record is required.
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*/
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#define OUTPUT_CHARACTER(ch) (void)putchar(ch)
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#endif
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#if (REDCONF_TASK_COUNT > 1U) && (REDCONF_API_POSIX == 1)
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/** Cast a TaskHandle_t (a pointer type) to uintptr_t.
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Usage of this macro deivate from MISRA-C:2012 Rule 11.4 (advisory). This
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macro is used for the FreeRTOS version of RedOsTaskId(). Some RTOSes
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natively use an integer for task IDs; others use pointers. RedOsTaskId()
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uses integers, FreeRTOS uses pointers; to reconcile this difference, the
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pointer must be cast to integer. This is fairly safe, since the resulting
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integer is never cast back to a pointer; and although the integer
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representation of a pointer is implementation-defined, the representation is
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irrelevant provided that unique pointers are converted to unique integers.
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As Rule 11.4 is advisory, a deviation record is not required. This notice
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is the only record of the deviation.
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*/
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#define CAST_TASK_PTR_TO_UINTPTR(taskptr) ((uintptr_t)(taskptr))
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#endif
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/** Ignore the return value of a function (cast to void)
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Usages of this macro deviate from MISRA C:2012 Directive 4.7, which states
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that error information must be checked immediately after a function returns
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potential error information.
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If asserts and output are enabled, then this macro is used to document that
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the return value of printf() is ignored. A failure of printf() does not
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impact the filesystem core, nor is there anything the filesystem can do to
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respond to such an error (especially since it occurs within an assert).
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Thus, the most reasonable action is to ignore the error.
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In the STM32 SDIO block device implementation, errors are also ignored in an
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IRQ interrupt handler. This is the most reasonable action to take for two
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reasons: (a) it would be dangerous to spend processor time responding to the
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error inside the IRQ handler; (b) it has been verified that the same error
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is propegated to the DiskRead/Write method, which does return the error to
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the core.
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In the Atmel SD/MMC block device implementation, error information from
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sd_mmc_read_capacity() is ignored. This is a reasonable action because all
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of the possible error conditions were eliminated by a previous check.
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sd_mmc_read_capacity() fails under the same conditions as
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sd_mmc_test_unit_ready(), which was checked ealier in the same function.
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In the mutex module, error information returned from the mutex release
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function is ignored when asserts are disabled. This is a reasonable action
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because the mutex release function (xSemaphoreGive) is documented only to
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fail if the mutex was not obtained correctly, which can be demonstrably
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avoided.
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As Directive 4.7 is required, a separate deviation record is required.
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*/
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#define IGNORE_ERRORS(fn) ((void) (fn))
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/** @brief Determine whether a pointer is aligned on a 32-bit boundary.
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This is used to determine whether a data buffer meets the requirements of
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the underlying block device implementation. When transferring data via
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DMA (Direct Memory Access) on an STM32 device, the data buffer must be cast
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as a uint32 pointer, and unexpected behavior may occur if the buffer is not
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aligned correctly.
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There is no way to perform this check without deviating from MISRA C rules
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against casting pointers to integer types. Usage of this macro deviates
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from MISRA C:2012 Rule 11.4 (advisory). The main rationale the rule cites
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against converting pointers to integers is that the chosen integer type may
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not be able to represent the pointer; this is a non-issue here since we use
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uintptr_t. The text says the rule still applies when using uintptr_t due to
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concern about unaligned pointers, but that is not an issue here since the
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integer value of the pointer is not saved and not converted back into a
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pointer and dereferenced. The result of casting a pointer to a sufficiently
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large integer is implementation-defined, but macros similar to this one have
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been used by Datalight for a long time in a wide variety of environments and
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they have always worked as expected.
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This deviation only occurs when using the STM32 SDIO block device
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implementation.
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As Rule 11.4 is advisory, a deviation record is not required. This notice
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is the only record of deviation.
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*/
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#define IS_UINT32_ALIGNED_PTR(ptr) (((uintptr_t)(ptr) & (sizeof(uint32_t) - 1U)) == 0U)
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/** @brief Cast a 32-bit aligned void pointer to a uint32 pointer.
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Usages of this macro deviate from MISRA C:2012 Rule 11.5 (advisory). A
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cast from a void pointer to an object pointer is discouraged because of
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potential alignment issues. However, this macro is only used to cast
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pointers that have already been tested to be 32-bit aligned, so the
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operation will be safe.
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This deviation only occurs when using the STM32 SDIO block device
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implementation.
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As rule 11.5 is advisory, a deviation record is not required. This notice
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is the only record of the deviation.
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*/
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#define CAST_UINT32_PTR(ptr) ((uint32_t *) (ptr))
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#endif
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