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Allow unaligned input/output for QSPI 

The code is written such that access to the data input/output happens word-by-word, and that means unaligned access is fine (though with a performance loss) on Cortex-M3/M4 devices.
pull/7825/head
Steven 2018-08-19 14:21:26 +02:00 committed by Steven Cooreman
parent 845a5beb30
commit e0d033bdd1
1 changed files with 8 additions and 4 deletions
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12
targets/TARGET_Silicon_Labs/TARGET_EFM32/qspi_api.c
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@ -163,8 +163,8 @@ qspi_status_t qspi_write(qspi_t *obj, const qspi_command_t *command, const void
QSPI_WriteConfig_TypeDef cfg = QSPI_WRITECONFIG_DEFAULT;
uint32_t to_write = *length;
// Enforce word-aligned and word-sized access
if ((to_write & 0x3) != 0 || ((uint32_t)data & 0x3) != 0) {
// Enforce word-sized access
if ((to_write & 0x3) != 0) {
return QSPI_STATUS_INVALID_PARAMETER;
}
@ -216,6 +216,8 @@ qspi_status_t qspi_write(qspi_t *obj, const qspi_command_t *command, const void
// Wait for the QSPI in case we're writing too fast
while (((obj->instance->SRAMFILL & _QSPI_SRAMFILL_SRAMFILLINDACWRITE_MASK) >> _QSPI_SRAMFILL_SRAMFILLINDACWRITE_SHIFT) >= 126);
// Unaligned access is fine on CM3/CM4 provided we stick to LDR/STR
// With the line below, the compiler can't really do anything else anyways
*((uint32_t*)QSPI0_MEM_BASE) = ((uint32_t*)data)[i/4];
}
@ -284,8 +286,8 @@ qspi_status_t qspi_read(qspi_t *obj, const qspi_command_t *command, void *data,
QSPI_ReadConfig_TypeDef cfg = QSPI_READCONFIG_DEFAULT;
uint32_t to_read = *length;
// Enforce word-aligned and word-sized access
if ((to_read & 0x3) != 0 || ((uint32_t)data & 0x3) != 0) {
// Enforce word-sized access
if ((to_read & 0x3) != 0) {
return QSPI_STATUS_INVALID_PARAMETER;
}
@ -353,6 +355,8 @@ qspi_status_t qspi_read(qspi_t *obj, const qspi_command_t *command, void *data,
// Wait for the FIFO in case we're reading too fast
while ((obj->instance->SRAMFILL & _QSPI_SRAMFILL_SRAMFILLINDACREAD_MASK) >> _QSPI_SRAMFILL_SRAMFILLINDACREAD_SHIFT == 0);
// Unaligned access is fine on CM3/CM4 provided we stick to LDR/STR
// With the line below, the compiler can't really do anything else anyways
((uint32_t*)data)[i/4] = *((uint32_t*)QSPI0_MEM_BASE);
}