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walkround for samd21 setup_packet overflow

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increase setup packet size from 8 to 12, since USB DMA controller is
suspected to overflow the buffer with 2 extra bytes
This commit is contained in:
hathach
2021-01-08 01:21:03 +07:00
parent 9f0b401f80
commit 60620dca42
1 changed files with 8 additions and 2 deletions
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10
src/portable/microchip/samd/dcd_samd.c
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@@ -37,14 +37,20 @@
/* MACRO TYPEDEF CONSTANT ENUM
*------------------------------------------------------------------*/
static TU_ATTR_ALIGNED(4) UsbDeviceDescBank sram_registers[8][2];
static TU_ATTR_ALIGNED(4) uint8_t _setup_packet[8];
// Setup packet is only 8 bytes in length. However under certain scenario,
// SAMD21 USB DMA controller is "suspected" to overwrite/overflow the setup_packet with 2 extra bytes.
// Which corrupt other variable and cause issue such as
// https://github.com/adafruit/circuitpython/issues/3912 (on macOS)
// Therefore we increase it to 12 bytes as walk-around until figuring out the root cause
static TU_ATTR_ALIGNED(4) uint8_t _setup_packet[8+4];
// ready for receiving SETUP packet
static inline void prepare_setup(void)
{
// Only make sure the EP0 OUT buffer is ready
sram_registers[0][0].ADDR.reg = (uint32_t) _setup_packet;
sram_registers[0][0].PCKSIZE.bit.MULTI_PACKET_SIZE = sizeof(_setup_packet);
sram_registers[0][0].PCKSIZE.bit.MULTI_PACKET_SIZE = sizeof(tusb_control_request_t);
sram_registers[0][0].PCKSIZE.bit.BYTE_COUNT = 0;
}