mirror of https://github.com/rusefi/rusefi-1.git
70 lines
1.6 KiB
C++
70 lines
1.6 KiB
C++
/**
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* @file zero_device.cpp
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*
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* @date Feb 12, 2021
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* @author Matthew Kennedy, (c) 2021
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*
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* This file implements a special block device that simply reports "no media"
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* Use it when you need to mount *something* but don't have an SD card available.
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*/
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#include "pch.h"
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#include <cstring>
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struct NullDevice {
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const struct BaseBlockDeviceVMT *vmt;
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_base_block_device_data
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};
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static bool nd_is_inserted(void*) {
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// This function is the whole point - we have no media!
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return false;
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}
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static bool nd_is_protected(void*) {
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return false;
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}
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static bool nd_return_success(void*) {
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return HAL_SUCCESS;
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}
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static bool nd_return_success_read(void*, uint32_t, uint8_t* buffer, uint32_t n) {
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// write zeroes to the buffer to prevent somebody reading random memory
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memset(buffer, 0, n);
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return HAL_SUCCESS;
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}
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static bool nd_return_success_write(void*, uint32_t, const uint8_t*, uint32_t) {
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return HAL_SUCCESS;
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}
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static bool nd_get_info(void*, BlockDeviceInfo* bdip) {
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// We have to report non-zero size here because Windows
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// will query the size of the block device even if we indicate
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// that the device has no media
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// If we report zeroes, it breaks USB until you unplug this device
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bdip->blk_num = 1000;
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bdip->blk_size = 512;
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return HAL_SUCCESS;
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}
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static const struct BaseBlockDeviceVMT ndVmt = {
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(size_t)0, // instanceOffset
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nd_is_inserted,
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nd_is_protected,
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// These functions just claim success to make the host happy
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nd_return_success,
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nd_return_success,
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nd_return_success_read,
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nd_return_success_write,
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nd_return_success,
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nd_get_info
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};
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// This device is always ready and has no state
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NullDevice ND1 = { &ndVmt, BLK_READY };
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