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Update STM driver changes for clarity 

- Use a switch statement rather than shifting and masking to compute
  the AlternateBytes value.
- Rename rounded_size to alt_bytes to clarify its purpose.
pull/11602/head
Kyle Kearney 2019-10-03 11:07:42 -07:00
parent 8c860524fb
commit 8e9877c212
1 changed files with 42 additions and 12 deletions
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54
targets/TARGET_STM/qspi_api.c
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@ -42,6 +42,40 @@
/* hence 2^(31+1), then FLASH_SIZE_DEFAULT = 1<<31 */
#define QSPI_FLASH_SIZE_DEFAULT 0x80000000
#if defined(OCTOSPI1)
static uint32_t get_alt_bytes_size(const uint32_t num_bytes)
{
switch (num_bytes) {
case 1:
return HAL_OSPI_ALTERNATE_BYTES_8_BITS;
case 2:
return HAL_OSPI_ALTERNATE_BYTES_16_BITS;
case 3:
return HAL_OSPI_ALTERNATE_BYTES_24_BITS;
case 4:
return HAL_OSPI_ALTERNATE_BYTES_32_BITS;
}
error("Invalid alt bytes size");
return 0xFFFFFFFF;
}
#else /* OCTOSPI1 */
static uint32_t get_alt_bytes_size(const uint32_t num_bytes)
{
switch (num_bytes) {
case 1:
return QSPI_ALTERNATE_BYTES_8_BITS;
case 2:
return QSPI_ALTERNATE_BYTES_16_BITS;
case 3:
return QSPI_ALTERNATE_BYTES_24_BITS;
case 4:
return QSPI_ALTERNATE_BYTES_32_BITS;
}
error("Invalid alt bytes size");
return 0xFFFFFFFF;
}
#endif /* OCTOSPI1 */
#if defined(OCTOSPI1)
qspi_status_t qspi_prepare_command(const qspi_command_t *command, OSPI_RegularCmdTypeDef *st_command)
{
@ -151,15 +185,15 @@ qspi_status_t qspi_prepare_command(const qspi_command_t *command, OSPI_RegularCm
}
// Round up to nearest byte - unused parts of byte act as dummy cycles
uint32_t rounded_size = ((command->alt.size - 1) >> 3) + 1;
uint32_t alt_bytes = ((command->alt.size - 1) >> 3) + 1;
// Maximum of 4 alt bytes
if (rounded_size > 4) {
if (alt_bytes > 4) {
error("Command param error: alt size exceeds maximum of 32 bits\n");
return QSPI_STATUS_ERROR;
}
// Unused bits in most significant byte of alt
uint8_t leftover_bits = (rounded_size << 3) - command->alt.size;
uint8_t leftover_bits = (alt_bytes << 3) - command->alt.size;
if (leftover_bits != 0) {
// Account for dummy cycles that will be spent in the alt portion of the command
uint8_t integrated_dummy_cycles = leftover_bits / alt_lines;
@ -176,9 +210,7 @@ qspi_status_t qspi_prepare_command(const qspi_command_t *command, OSPI_RegularCm
st_command->AlternateBytes = command->alt.value;
}
/* command->AlternateBytesSize needs to be shifted by OCTOSPI_CCR_ABSIZE_Pos */
// 0b00 = 1 byte, 0b01 = 2 bytes, 0b10 = 3 bytes, 0b11 = 4 bytes
st_command->AlternateBytesSize = ((rounded_size - 1) << OCTOSPI_CCR_ABSIZE_Pos) & OCTOSPI_CCR_ABSIZE_Msk;
st_command->AlternateBytesSize = get_alt_bytes_size(alt_bytes);
}
switch (command->data.bus_width) {
@ -283,14 +315,14 @@ qspi_status_t qspi_prepare_command(const qspi_command_t *command, QSPI_CommandTy
}
// Round up to nearest byte - unused parts of byte act as dummy cycles
uint32_t rounded_size = ((command->alt.size - 1) >> 3) + 1;
uint32_t alt_bytes = ((command->alt.size - 1) >> 3) + 1;
// Maximum of 4 alt bytes
if (rounded_size > 4) {
if (alt_bytes > 4) {
return QSPI_STATUS_ERROR;
}
// Unused bits in most significant byte of alt
uint8_t leftover_bits = (rounded_size << 3) - command->alt.size;
uint8_t leftover_bits = (alt_bytes << 3) - command->alt.size;
if (leftover_bits != 0) {
// Account for dummy cycles that will be spent in the alt portion of the command
uint8_t integrated_dummy_cycles = leftover_bits / alt_lines;
@ -306,9 +338,7 @@ qspi_status_t qspi_prepare_command(const qspi_command_t *command, QSPI_CommandTy
st_command->AlternateBytes = command->alt.value;
}
/* command->AlternateBytesSize needs to be shifted by QUADSPI_CCR_ABSIZE_Pos */
// 0b00 = 1 byte, 0b01 = 2 bytes, 0b10 = 3 bytes, 0b11 = 4 bytes
st_command->AlternateBytesSize = ((rounded_size - 1) << QUADSPI_CCR_ABSIZE_Pos) & QUADSPI_CCR_ABSIZE_Msk;
st_command->AlternateBytesSize = get_alt_bytes_size(alt_bytes);
}
switch (command->data.bus_width) {