Hi Philipp,
-----Original Message----- From: Philipp Tomsich [mailto:philipp.tomsich@theobroma-systems.com] Sent: Friday, November 30, 2018 2:40 PM To: u-boot@lists.denx.de Cc: Tom Rini trini@konsulko.com; Philipp Tomsich philipp.tomsich@theobroma-systems.com; Mario Six mario.six@gdsys.cc; Michal Simek michal.simek@xilinx.com; Simon Glass sjg@chromium.org; Masahiro Yamada yamada.masahiro@socionext.com; Alexey Brodkin alexey.brodkin@synopsys.com; Alex Kiernan alex.kiernan@gmail.com; Eric Nelson eric@nelint.com; Marek Vasut marek.vasut@gmail.com; Jörg Krause joerg.krause@embedded.rocks; Adam Ford aford173@gmail.com; Stephen Warren swarren@nvidia.com; Angelo Dureghello angelo@sysam.it; Tuomas Tynkkynen tuomas.tynkkynen@iki.fi; Eugeniu Rosca roscaeugeniu@gmail.com Subject: [PATCH 1/6] Kconfig: Migrate BOUNCE_BUFFER
The bounce buffer is used by a few drivers (most of the MMC drivers) to overcome limitations in their respective DMA implementation.
This moves the configuration to Kconfig and makes it user-selectable (even though it will be a required feature to make those drivers work): the expected usage is for drivers depending on this to 'select' it unconditionally from their respective Kconfig.
Signed-off-by: Philipp Tomsich philipp.tomsich@theobroma-systems.com
common/Kconfig | 8 ++++++++ scripts/config_whitelist.txt | 1 - 2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/common/Kconfig b/common/Kconfig index 57bd16d..f45e066 100644 --- a/common/Kconfig +++ b/common/Kconfig @@ -645,6 +645,14 @@ config DISPLAY_BOARDINFO_LATE the relocation phase. The board function checkboard() is called to do this.
+config BOUNCE_BUFFER
- bool "Include bounce buffer API"
- help
Some peripherals support DMA from a subset of physicallyaddressable memory only. To support such peripherals, thebounce buffer API uses a temporary buffer: it copies datato/from DMA regions while managing cache operations.
IIRC I decided to use bounce buffer just to make sure data we pass to the DMA is properly aligned. Not sure though if that's a valid use-case for it but if it is IMHO it worth mentioning here in this help message.
-Alexey