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QSPIFBlockDevice: fix misconception in minimum program size 

Prior to this PR, the minimum program size (QSPI_MIN_PROG_SIZE) of
QSPIFBlockDevice was 256 by default and 512 for some targets.
Those values were in fact page sizes, not program sizes.

Here's an explanation:
* Most QSPI flashes can be programmed to a granularity of a
  single byte or a few bytes - no need to be a whole page.
  This should be the value of QSPI_MIN_PROG_SIZE. Applications
  need to align buffer sizes to this granularity when
  programming QSPI flashes.
* Each sending of the underlying QSPI program signal requires
  destination bytes to be located within the same page.
  If a QSPIFBlockDevice::program() call crosses page boundaries,
  this function breaks down the operation into multiple chunks,
  so it's not a concern for the application.

So this PR changes the default program size to 1 (byte), and
for targets with a 4-byte (1-word) read size it overrides the
program size.

Note: No config is needed for the page size, as it comes from
the SFDP table parsed during initialisation.
pull/13848/head
Lingkai Dong 2020-11-03 14:22:13 +00:00
parent 66c05ddbf8
commit c61445a787
1 changed files with 8 additions and 5 deletions
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13
storage/blockdevice/COMPONENT_QSPIF/mbed_lib.json
View File

@ -18,7 +18,7 @@
"QSPI_POLARITY_MODE": 0, "QSPI_POLARITY_MODE": 0,
"QSPI_FREQ": "40000000", "QSPI_FREQ": "40000000",
"QSPI_MIN_READ_SIZE": "1", "QSPI_MIN_READ_SIZE": "1",
"QSPI_MIN_PROG_SIZE": "256" "QSPI_MIN_PROG_SIZE": "1"
}, },
"target_overrides": { "target_overrides": {
"MX25R6435F": { "MX25R6435F": {
@ -37,15 +37,18 @@
"MCU_NRF52840": { "MCU_NRF52840": {
"QSPI_FREQ": "32000000", "QSPI_FREQ": "32000000",
"QSPI_MIN_READ_SIZE": "4", "QSPI_MIN_READ_SIZE": "4",
"QSPI_MIN_PROG_SIZE": "256" "QSPI_MIN_PROG_SIZE": "4"
}, },
"MCU_PSOC6": { "MCU_PSOC6": {
"QSPI_FREQ": "50000000", "QSPI_FREQ": "50000000"
"QSPI_MIN_PROG_SIZE": "512"
}, },
"EFM32GG11_STK3701": { "EFM32GG11_STK3701": {
"QSPI_MIN_READ_SIZE": "4", "QSPI_MIN_READ_SIZE": "4",
"QSPI_MIN_PROG_SIZE": "256" "QSPI_MIN_PROG_SIZE": "4"
},
"MCU_LPC546XX": {
"QSPI_MIN_READ_SIZE": "4",
"QSPI_MIN_PROG_SIZE": "4"
} }
} }
} }