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ikwzm / udmabuf

User space mappable dma buffer device driver for Linux.

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support for microblaze ?

doonny opened this issue · comments

commented

Hi, this is a very useful tool. Is it possible to add support for microblaze processor ?

commented

Thank you for the issue.

I made u-dma-buf for arm or arm64.
I have never tried to work with microbraze prossor.

commented

hi @ikwzm thx for the reply. I have successfully compiled the udmabuf driver for microblaze processor using petalinux 2021.2.
The driver can be successfully loaded into kernel:

root@vc709_plnx_21:~# insmod u-dma-buf.ko udmabuf0=1048576
u-dma-buf u-dma-buf.0: driver probe start.
u-dma-buf udmabuf0: driver version = 3.2.5
u-dma-buf udmabuf0: major number = 250
u-dma-buf udmabuf0: minor number = 0
u-dma-buf udmabuf0: phys address = 0xaed00000
u-dma-buf udmabuf0: buffer size = 1048576
u-dma-buf u-dma-buf.0: driver installed.

and I could observe from /proc/meminfo that CMA space has also been consumed to allocate the buffer.

But I could not find the dev node under /dev:

root@vc709_plnx_21:~# ls /dev/u*
/dev/urandom

Could you give some advice what might be the problem ?

commented

Thank you for valuable information.

I have some questions

  • Q1 What about /sys/class/u-dma-buf ?
  • Q2 Is the udev daemon running?
commented

@ikwzm thx for the advice, after enable udev in petalinux, the u-dma-buf module can be loaded upon bootup:

INIT: version 2.97 booting
mount: mounting sysfs on /sys failed: Device or resource busy
/etc/rcS.d/S04mdev: line 10: /proc/sys/kernel/hotplug: No such file or directory
Starting udev
udevd[83]: starting version 3.2.9
random: udevd: uninitialized urandom read (16 bytes read)
random: udevd: uninitialized urandom read (16 bytes read)
random: udevd: uninitialized urandom read (16 bytes read)
udevd[84]: starting eudev-3.2.9
u_dma_buf: loading out-of-tree module taints kernel.
u-dma-buf udmabuf@0x00: driver probe start.
u-dma-buf udmabuf0: driver version = 3.2.5
u-dma-buf udmabuf0: major number   = 251
u-dma-buf udmabuf0: minor number   = 0
u-dma-buf udmabuf0: phys address   = 0xa7d00000
u-dma-buf udmabuf0: buffer size    = 67108864
u-dma-buf udmabuf@0x00: driver installed.
bootlogd: /dev/ttyUL0Fri Mar  9 12:34:56 UTC 2018

But still could not find it under /dev:

root@vc709_plnx_21:~# ls /dev/u*
/dev/urandom

There are some error in the boot logs after adding udev to petalinux, not sure if it was the cause:

u-dma-buf udmabuf0: phys address   = 0xa7d00000
u-dma-buf udmabuf0: buffer size    = 67108864
u-dma-buf udmabuf@0x00: driver installed.
bootlogd: /dev/ttyUL0Fri Mar  9 12:34:56 UTC 2018
sh: malloc.c:2394: sysmalloc: Assertion `(old_top == initial_top (av) && old_size == 0) || ((unsigned long) (old_size) >= MINSIZE && prev_inuse (old_top) && ((unsigned long) old_end & (pa.
/etc/rcS.d/S37populate-volatile.sh: line 154:   198 Done                    sed 's/#.*//' "${CFGFILE}"
       199 Aborted                 | while read -r TTYPE TUSER TGROUP TMODE TNAME TLTARGET; do
    test -z "${TLTARGET}" && continue; TNAME=${ROOT_DIR}${TNAME}; [ "${VERBOSE}" != "no" ] && echo "Checking for -${TNAME}-."; [ "${TTYPE}" = "l" ] && { TSOURCE="$TLTARGET"; [ "${VERBOSE}"
        mount --bind \"${TSOURCE}\" \"${TNAME}\""; test "$VOLATILE_ENABLE_CACHE" = yes && echo "$EXEC" >> /etc/volatile.cache.build; continue; }; [ -L "${TNAME}" ] && { [ "${VERBOSE}" != n
        TNAME="$(echo "${TNAME}" | sed -e 's@\(.*\)/.*@\1@')/${NEWNAME}"; [ "${VERBOSE}" != "no" ] && echo "Converted relative linktarget to absolute path -${TNAME}-.";
    else
        TNAME="${NEWNAME}"; [ "${VERBOSE}" != "no" ] && echo "Using absolute link target -${TNAME}-.";
    fi; }; case "${TTYPE}" in
        "f")
            [ "${VERBOSE}" != "no" ] && echo "Creating file -${TNAME}-."; TSOURCE="$TLTARGET"; [ "${TSOURCE}" = "none" ] && TSOURCE=""; create_file "${TNAME}" "${TSOURCE}" &
        ;;
        "d")
            [ "${VERBOSE}" != "no" ] && echo "Creating directory -${TNAME}-."; mk_dir "${TNAME}"
        ;;
        *)
            [ "${VERBOSE}" != "no" ] && echo "Invalid type -${TTYPE}-."; continue
        ;;
    esac;
done
urandom_read: 1 callbacks suppressed
random: dd: uninitialized urandom read (512 bytes read)
Configuring packages on first boot....
 (This may take several minutes. Please do not power off the machine.)
commented

After changing selecting the whole eudev package rather only selecting libudev, the errors was gone in the boot log.
But still could not see the udmabuf device under /dev/

commented

I'm sorry I can't be of any help.
I'm not familiar with eudev.
You may want to check the debug information with udevadm monitor.
Please let us know if you have any new information.

commented

hi @ikwzm , following are the messages printed when add and move the drivier :

root@vc709_plnx_21:~# udevadm monitor
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[818.755730] remove   /devices/virtual/misc/u-dma-buf-mgr (misc)
KERNEL[818.803936] remove   /devices/platform/u-dma-buf.0/u-dma-buf/udmabuf0 (u-dma-buf)
KERNEL[818.809830] unbind   /devices/platform/u-dma-buf.0 (platform)
KERNEL[818.816036] remove   /devices/platform/u-dma-buf.0 (platform)
KERNEL[818.829952] remove   /bus/platform/drivers/u-dma-buf (drivers)
KERNEL[818.835897] remove   /class/u-dma-buf (class)
KERNEL[818.838346] remove   /module/u_dma_buf (module)
KERNEL[832.295301] add      /module/u_dma_buf (module)
KERNEL[832.336945] add      /class/u-dma-buf (class)
KERNEL[832.350402] add      /bus/platform/drivers/u-dma-buf (drivers)
KERNEL[832.356573] add      /kernel/software_nodes/node1 (software_nodes)
KERNEL[832.359202] add      /devices/platform/u-dma-buf.0 (platform)
KERNEL[832.416661] add      /devices/platform/u-dma-buf.0/u-dma-buf/udmabuf0 (u-dma-buf)
KERNEL[832.423696] bind     /devices/platform/u-dma-buf.0 (platform)
KERNEL[832.511984] add      /devices/virtual/misc/u-dma-buf-mgr (misc)

Is the information sufficient for you

commented

In ZynqMP-FPGA-Linux, the output is as follows.

root@debian-fpga:/home/fpga# udevadm monitor
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[1989.940970] add      /module/u_dma_buf (module)
KERNEL[1989.942721] add      /class/u-dma-buf (class)
KERNEL[1989.942789] add      /bus/platform/drivers/u-dma-buf (drivers)
KERNEL[1989.942827] add      /kernel/software_nodes/node5 (software_nodes)
KERNEL[1989.942872] add      /devices/platform/u-dma-buf.0 (platform)
UDEV  [1989.943530] add      /module/u_dma_buf (module)
UDEV  [1989.944906] add      /bus/platform/drivers/u-dma-buf (drivers)
UDEV  [1989.944986] add      /class/u-dma-buf (class)
KERNEL[1989.945735] add      /devices/platform/u-dma-buf.0/u-dma-buf/udmabuf0 (u-dma-buf)
UDEV  [1989.947321] add      /devices/platform/u-dma-buf.0 (platform)
UDEV  [1989.948651] add      /kernel/software_nodes/node5 (software_nodes)
UDEV  [1989.950287] add      /devices/platform/u-dma-buf.0/u-dma-buf/udmabuf0 (u-dma-buf)
KERNEL[1989.979179] bind     /devices/platform/u-dma-buf.0 (platform)
KERNEL[1989.979285] add      /devices/virtual/misc/u-dma-buf-mgr (misc)
UDEV  [1989.980528] bind     /devices/platform/u-dma-buf.0 (platform)
UDEV  [1989.980794] add      /devices/virtual/misc/u-dma-buf-mgr (misc)

As you can see, there is a UDEV line. The UDEV line shows the udev event handler that has completed.

On the other hand, your log does not have a UDEV line. I guess this is because the udev event is not happening in some settings. Check udev settings.