Hide unused code under #ifdef notyet (in one case the only caller is under
that same ifdef), or if it is arm (not arm64) specific code under the
__arm__ ifdef to not yield -Wunused-function warnings during the arm64
kernel compile.
MFC after: 2 weeks
front-end doesn't support SDMA or the latter implements a platform-
specific transfer method instead. While at it, factor out allocation
and freeing of SDMA resources to sdhci_dma_{alloc,free}() in order to
keep the code more readable when adding support for ADMA variants.
o Base the size of the SDMA bounce buffer on MAXPHYS up to the maximum
of 512 KiB instead of using a fixed 4-KiB-buffer. With the default
MAXPHYS of 128 KiB and depending on the controller and medium, this
reduces the number of SDHCI interrupts by a factor of ~16 to ~32 on
sequential reads while an increase of throughput of up to ~84 % was
seen.
Front-ends for broken controllers that only support an SDMA buffer
boundary of a specific size may set SDHCI_QUIRK_BROKEN_SDMA_BOUNDARY
and supply a size via struct sdhci_slot. According to Linux, only
Qualcomm MSM-type SDHCI controllers are affected by this, though.
Requested by: Shreyank Amartya (unconditional bump to 512 KiB)
o Introduce a SDHCI_DEPEND macro for specifying the dependency of the
front-end modules on the sdhci(4) one and bump the module version
of sdhci(4) to 2 via an also newly introduced SDHCI_VERSION in order
to ensure that all components are in sync WRT struct sdhci_slot.
o In sdhci(4):
- Make pointers const were applicable,
- replace a few device_printf(9) calls with slot_printf() for
consistency, and
- sync some local functions with their prototypes WRT static.
SDHOST is another SD controller that is present on Raspberry Pi (the
other one is SDHC and handled by bcm2835_sdhci driver). Both
controllers are capable of providing interface to SD card, actual
configuration can be set in dtb file. At the moment custom DTBs for
RPi/RPi2 have sdhost node disabled. On RPi3 sdhost is disabled in
snapshot images by applying mmc.dtbo overlay. To enalbe both devices
user has to edit config.txt on FAT partition and remove or comment
"dtoverlay=mmc" line.
When no overlay applied on RPi3 SDHOST controls SD card and SDHC
interface can be used for SDIO. mmc.dtbo overlay disables SDHOST node
and switches SD card over to SDHC. Likewise sdhost.dtbo overlay (not
currently included in snapshot image, but can be obtained from firmare
repo[1]) disabled SDHC node and switch SD card over to SDHOST.
[1] https://github.com/raspberrypi/firmware/tree/master/boot/overlays
Submitted by: Klaus P. Ohrhallinger <k@7he.at>
Differential Revision: https://reviews.freebsd.org/D14168
