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Restricted the size of all memory access commands to ensure that no more than two packets are sent to and from EDBG debug tools

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2022-12-18 19:25:40 +00:00
parent f64a14b04a
commit 09fc5b73f2
1 changed files with 12 additions and 51 deletions
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63
src/DebugToolDrivers/Protocols/CMSIS-DAP/VendorSpecific/EDBG/AVR/EdbgAvr8Interface.cpp
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@@ -1659,7 +1659,18 @@ namespace Bloom::DebugToolDrivers::Protocols::CmsisDap::Edbg::Avr
return this->maximumMemoryAccessSizePerRequest;
}
return std::nullopt;
/*
* EDBG AVR8 debug tools behave in a really weird way when receiving or responding with more than two packets
* for a single memory access command. The data they read/write in this case appears to be wrong.
*
* To address this, we make sure we only issue memory access commands that will result in no more than two
* packets being sent to and from the debug tool.
*
* The -30 is to accommodate for the bytes in the command that are not part of the main payload of the command.
*/
return static_cast<Targets::TargetMemorySize>(
(this->edbgInterface->getUsbHidInputReportSize() - 30) * 2
);
}
TargetMemoryBuffer EdbgAvr8Interface::readMemory(
@@ -1759,56 +1770,6 @@ namespace Bloom::DebugToolDrivers::Protocols::CmsisDap::Edbg::Avr
return output;
}
if (
type != Avr8MemoryType::FLASH_PAGE
&& type != Avr8MemoryType::SPM
&& type != Avr8MemoryType::APPL_FLASH
&& type != Avr8MemoryType::BOOT_FLASH
&& type != Avr8MemoryType::EEPROM_PAGE
) {
/*
* EDBG AVR8 debug tools behave in a really weird way when responding with more than two packets
* for a single read (non-flash) memory command. The data they return in this case appears to be of little
* use.
*
* To address this, we make sure we only issue read memory commands that will result in no more than two
* response packets. For calls that require more than this, we simply split them into numerous calls.
*/
/*
* The subtraction of 20 bytes here is just to account for any other bytes included in the response
* that isn't actually the memory data (like the command ID, version bytes, etc). I could have sought the
* actual value but who has the time. It won't exceed 20 bytes. Bite me.
*/
const auto singlePacketSize = static_cast<std::uint32_t>(this->edbgInterface->getUsbHidInputReportSize() - 20);
const auto totalResponsePackets = std::ceil(static_cast<float>(bytes) / static_cast<float>(singlePacketSize));
const auto totalReadsRequired = static_cast<std::uint16_t>(std::ceil(static_cast<float>(totalResponsePackets) / 2));
if (totalResponsePackets > 2) {
/*
* This call to readMemory() will result in more than two response packets, so split it into multiple
* calls that will result in no more than two response packets per call.
*/
auto output = TargetMemoryBuffer();
for (auto i = 1; i <= totalReadsRequired; i++) {
const auto bytesToRead = static_cast<TargetMemorySize>(
(bytes - output.size()) > (singlePacketSize * 2)
? (singlePacketSize * 2) : bytes - output.size()
);
auto data = this->readMemory(
type,
static_cast<TargetMemoryAddress>(startAddress + output.size()),
bytesToRead,
excludedAddresses
);
std::move(data.begin(), data.end(), std::back_inserter(output));
}
return output;
}
}
const auto responseFrame = this->edbgInterface->sendAvrCommandFrameAndWaitForResponseFrame(
ReadMemory(
type,