diff options
| author | Gregory Nutt <gnutt@nuttx.org> | 2015-01-08 06:23:42 -0600 |
|---|---|---|
| committer | Gregory Nutt <gnutt@nuttx.org> | 2015-01-08 06:23:42 -0600 |
| commit | 3cfb3001c68d449f0b59586bca112bf5a2e226fa (patch) | |
| tree | 6b44391374480c4fd0210992945de74f35b85e64 /nuttx/drivers/mmcsd/Kconfig | |
| parent | 982650a1b30076732fee025a63ec151fc0f3dcb1 (diff) | |
| download | nuttx-3cfb3001c68d449f0b59586bca112bf5a2e226fa.tar.gz nuttx-3cfb3001c68d449f0b59586bca112bf5a2e226fa.tar.bz2 nuttx-3cfb3001c68d449f0b59586bca112bf5a2e226fa.zip | |
MMCSD SDIO: Add support for a new SDWAIT_WRCOMPLETE condition. The previous logic used a busy-wait loop to pool the card R1 start to determine when the card was ready for the next transfer. That busy-wait can be quite long -- hundreds of milliseconds. And alternative is to look the the SD D0 pin which will change state when the card is no longer busy.
This logic implements a change the avoids the busy-wait poll by reconfiguring the SD D0 pin as a GPIO interrupt, then waiting for the card to becom ready without taking up CPU cycles.
This change is conditioned on CONFIG_MMCSD_SDIOWATI_WRCOMPLETE and is currenlty only implemented for the STM32 SDIO driver.
From David Sidrane
Diffstat (limited to 'nuttx/drivers/mmcsd/Kconfig')
| -rwxr-xr-x[-rw-r--r--] | nuttx/drivers/mmcsd/Kconfig | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/nuttx/drivers/mmcsd/Kconfig b/nuttx/drivers/mmcsd/Kconfig index 4949cee1f..f78232ebb 100644..100755 --- a/nuttx/drivers/mmcsd/Kconfig +++ b/nuttx/drivers/mmcsd/Kconfig @@ -38,6 +38,23 @@ config MMCSD_HAVECARDDETECT SDIO driver card detection is 100% accurate +config MMCSD_SDIOWAIT_WRCOMPLETE + bool "Use SDIO_D Busy to detect Write Complete" + default n + ---help--- + SDIO driver will use SDIO_D Busy signalling to detect Write Complete. + This option when selected, will enable the MMCSD driver to use the + underlying (stm32_sdio only) drivers implementation of the SD specs + SDIO_D Busy signalling to detect Write Complete. This will avoid + potentially very long (600Ms+) busy waiting in the MMCSD driver. + + To implement SDIO_D Busy signalling, the underlying driver must + be capable of switching the GPIO_SDIO_D0 to be a rising edge sensitive + interrupt pin. It must then, condition that pin to detect the rising edge + on receipt of SDWAIT_WRCOMPLETE in the SDIO_WAITENABLE call and + return it back to regular SDIO mode, when either the ISR fires or pin is + found to be high in the SDIO_EVENTWAIT call. + config MMCSD_SPI bool "MMC/SD SPI transfer support" default y |