devb-sdmmc-xzynq

Generic driver for SDHI memory card, MMC, and eMMC on the Xilinx KV260

Syntax:

devb-sdmmc-xzynq    [cam cam_options]
                    [sdmmc sdmmc_option...]
                    [sdio sdio_option...]
                    [blk io-blk_option..]

Runs on:

QNX OS

Options:

Note:

Use commas (,) to separate the options. You can put the blk, cam, sdmmc and sdio groups of options in any order.

cam options

async=[priority]: Perform CPU cache invalidation after an I/O operation in a thread at "priority". In some cases, and on some boards, this can provide a performance boost. Default off, priority 21.
bounce=[size]: This option specifies the size of bounce buffer to use. The bounce buffer acts as an intermediate buffer for doing transfers to/from the media. Bounce buffers are useful for devices which cannot access the full range of memory available to the CPU (32 vs 64-bit architecture etc). When used, size should be sufficiently large such that the CAM library doesn't fragment the I/O requests from io-blk, this will show markedly better performance. This option will automatically be enabled when cached memory buffer usage is disabled or when the hw doesn't support snooping. The size argument can include a case-insensitve suffix that indicates the units: B (bytes; the default), K (kilobytes), M (megabytes), or P (pages). The default size=32k.
cache=[on|off]: Turn on/off usage of cached memory buffers. Default on.
lun=mask: Enable Logical Unit Number (LUN) scan for the devices specified in mask. The mask is a hex bitmask specifying which IDs to scan for; the default is 0x00.
maxio=wr : rd: Set max I/O write, read blocks. Default 4096, limited by device.
noio: Completely remove the IO ability. Both ThreadCtl(_NTO_TCTL_IO) and ThreadCtl(_NTO_TCTL_IO_PRIV) won't be called.
nopriv: Don't call ThreadCtl(_NTO_TCTL_IO_PRIV).
pnp: Enable CAM plug and play (i.e. don't exit at startup when no devices are found). Default off.
resmgr=m:l:h:d: Enable /dev/camX/XXX interface and set max/lo/hi/devno thread pool parameters (default: "5:1:2:-1").
user=UID:GID: Operate as the specified user (UID) and group IDs (GID). The driver retains the necessary process-manager abilities.
smmu=[on|off]: Turn on/off (1/0) the use of IO MMU protection services. Default off.
verbose: Be verbose: display full information about SCSI units (devices) on startup.

mem options:

name=name: Typed memory name to use. Default sysram&below4G. See also blk layer option for typed memory.

sdmmc options:

The sdmmc options control the driver's interface to the SD/MMC device. If there are multiple SD/MMC devices, you can repeat these options for each controller. Remember, however, to specify the sdmmc keyword before each controller's set of options.

bkops=[on/auto]: Value 'on' = Manual background operations (WARNING: permanent setting); Value 'auto' = Device background operations.
busno=bus: The bus number of the SDIO controller.
bs=[options]: Set board specific options
cache=on: Enable eMMC/SD volatile cache.
partitions=on: Enable the eMMC partitions.
powman=[name]: Connect to powerman. Dflts: No connect, [name]=devb-sdmmc-variant.
priority=prio: Set the priority of the processing thread. Dflt 21.
pwroff_notify=[short/long]: Set power off notification mode for emmc [short/long].
relwr=on: Enable eMMc reliable write. Dflt off.
verbose=[level]: Set the verbosity level.

sdio options:

The sdio options control the driver's interface to the SD/MMC host controller. If there are multiple host controllers, you can repeat these options for each controller. Remember, however, to specify the sdio keyword before each controller's set of options.

verbose=[level]: Set the SDIO verbosity level.
hc=name: The name of host controller.
vid=vid: The vendor id of the controller.
did=did: The device id of the controller.
idx=idx: The index of the controller in the machine, where idx is a value between 0 and the number of adapters.
addr=addr: The address of the interface.
irq=req: The interrupt used by the controller.
dma=chnl: The DMA channel to use.
clk=clk: Set the operational clock.
~bmstr: Disable DMA.
~ac12: Disable AC12. Dflt on.
~ac23: Disable AC23. Dflt on.
bw=[~]bw: Set/Clear bus widths (4, 8).
timing=[~]timing: Set/Clear timings (hs, ddr, sdr12, sdr25, sdr50, sdr104, hs200, hs400, hs400es).
pm=idle:sleep: Set the pwr mgnt idle/sleep time in ms. Dflt 100:10000 ms.
emmc: An eMMC device is connected to the interface.
hs=options: Host specific options.
bs=options: Board specific options.
nowp: Disable write protect detection.
drv_type=drv_type: Driver strength value for the HS_TIMING register (0, 1, 2, 3, 4). Dflt 0.

Page updated: October 24, 2025