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    SubjectRe: Uartlite - ulite_transmit
    Hi Peter,

    sorry for delay. I had to look at another issue.

    Below is full log:
    1. I setup baudrate to 50. (It could be possible to set it up to 0 too)
    That's why I think that doesn't matter what baudrate is setup.

    2. You see where ulite_startup is called. It is called only once.

    3. You see that there is no call __uart_wait_until_sent(). It could be
    called for ASYNC mode. The second thing is __uart_wait_until_sent
    function is checking if tx fifo is empty not circ buffer is empty.

    4. Next thing is that in uart_close. port->count is 2 which means that
    the executing path is
    if (port->count) {
    spin_unlock_irqrestore(&port->lock, flags);
    goto done;
    }
    which means that there is no chance to call __uart_wait_until_sent
    function anyway.

    5. I did one modification to add simple while loop till circ buffer is
    empty to the same location to see what happen (timouts are bogus values).

    if (port->count) {
    spin_unlock_irqrestore(&port->lock, flags);
    printk("************ %x %x\n", (&uport->state->xmit)->tail,
    (&uport->state->xmit)->head);
    while (!uart_circ_empty(&uport->state->xmit)) {
    msleep_interruptible(jiffies_to_msecs((uport->timeout - HZ/50)));
    if (signal_pending(current))
    break;
    if (time_after(jiffies, jiffies + uport->timeout))
    break;
    }
    printk("************\n");
    goto done;
    }

    Here is log: (Between **** you can see what chars are not printed)

    NET: Registered protocol family 17
    uart_open(0) called
    ulite_startup ------------------------
    Freeing unused kernel memory: 11235k freed
    Mounting proc:
    Mounting var:
    Populating /var:
    Running local start scripts.
    Mounting sysfs:
    mdev: initialising /dev
    Mounting /etc/config:
    Populating /etc/config:
    flatfsd: Created 8 configuration files (168 bytes)
    Mounting denet eth0: Promiscuous mode disabled.
    vpts:
    Setting hostname:
    Bringing up network interfaces:
    udhcpc (v1.14.3) started
    Sending discover...
    Sending seuart_open(0) called
    lect for 192.168uart_close(0) called, port->count 2
    ************ 172 362
    .0.100...
    Lease of 192.168.0.100 obtained, lease time 7200
    adding dns 172.16.0.5
    adding dns 172.16.10.1
    Starting portmap:

    Welcome to
    _____ _ _ _
    | ___ \ | | | | (_)
    | |_/ / ___ | |_ __ _ | | _ _ __ _ _ __ __
    | __/ / _ \| __| / _` || | | || '_ \ | | | |\ \/ /
    | | | __/| |_ | (_| || |____| || | | || |_| | > <
    \_| \___| \__| \__,_|\_____/|_||_| |_| \__,_|/_/\_\

    on Xilinx-SP605-LTP-full-WB-pc-msr-next-22-watch-wt-mdm

    ************
    uart_open(0) called
    uart_flush_buffer(0) called

    Xilinx-SP605-LTP-full-WB-pc-msr-next-22-watch-wt-mdm login:



    I think that will be good to check if circ buffer is empty. As you
    suggest uart_close function will be probably the best place.

    Any other suggestion?

    Thanks,
    Michal




    Full log with debug messages:

    Linux version 2.6.37-00014-g85eb775-dirty (monstr@monstr.eu) (gcc
    version 4.1.2) #15 Sun Jan 16 08:43:08 CET 2011
    less 8
    setup_cpuinfo: initialising
    setup_cpuinfo: Using full CPU PVR support
    cache: wt_msr_noirq
    setup_memory: max_mapnr: 0x8000
    setup_memory: min_low_pfn: 0x48000
    setup_memory: max_low_pfn: 0x50000
    On node 0 totalpages: 32768
    free_area_init_node: node 0, pgdat c029f0b8, node_mem_map c0dab000
    Normal zone: 256 pages used for memmap
    Normal zone: 0 pages reserved
    Normal zone: 32512 pages, LIFO batch:7
    pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
    pcpu-alloc: [0] 0
    Built 1 zonelists in Zone order, mobility grouping on. Total pages: 32512
    Kernel command line: console=ttyUL0,50
    PID hash table entries: 512 (order: -1, 2048 bytes)
    Dentry cache hash table entries: 16384 (order: 4, 65536 bytes)
    Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)
    Memory: 115776k/131072k available
    NR_IRQS:32
    xlnx,xps-intc-1.00.a #0 at 0xc8000000, num_irq=8, edge=0x93
    xlnx,xps-timer-1.00.a #0 at 0xc8004000, irq=4
    microblaze_timer_set_mode: shutdown
    microblaze_timer_set_mode: periodic
    Calibrating delay loop... 43.90 BogoMIPS (lpj=87808)
    pid_max: default: 32768 minimum: 301
    Mount-cache hash table entries: 512
    NET: Registered protocol family 16
    bio: create slab <bio-0> at 0
    Switching to clocksource microblaze_clocksource
    microblaze_timer_set_mode: oneshot
    NET: Registered protocol family 2
    IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
    TCP established hash table entries: 4096 (order: 3, 32768 bytes)
    TCP bind hash table entries: 4096 (order: 2, 16384 bytes)
    TCP: Hash tables configured (established 4096 bind 4096)
    TCP reno registered
    UDP hash table entries: 256 (order: 0, 4096 bytes)
    UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
    NET: Registered protocol family 1
    RPC: Registered udp transport module.
    RPC: Registered tcp transport module.
    RPC: Registered tcp NFSv4.1 backchannel transport module.
    Skipping unavailable RESET gpio -2 (reset)
    GPIO pin is already allocated
    JFFS2 version 2.2. (NAND) (SUMMARY) © 2001-2006 Red Hat, Inc.
    Block layer SCSI generic (bsg) driver version 0.4 loaded (major 254)
    io scheduler noop registered
    io scheduler deadline registered
    io scheduler cfq registered (default)
    84400000.debug: ttyUL0 at MMIO 0x84400000 (irq = 7) is a uartlite
    console [ttyUL0] enabled
    Xilinx SystemACE device driver, major=254
    86000000.flash: Found 1 x16 devices at 0x0 in 16-bit bank. Manufacturer
    ID 0x000089 Chip ID 0x008919
    Intel/Sharp Extended Query Table at 0x010A
    Intel/Sharp Extended Query Table at 0x010A
    Intel/Sharp Extended Query Table at 0x010A
    Intel/Sharp Extended Query Table at 0x010A
    Intel/Sharp Extended Query Table at 0x010A
    Using buffer write method
    Using auto-unlock on power-up/resume
    cfi_cmdset_0001: Erase suspend on write enabled
    erase region 0: offset=0x0,size=0x20000,blocks=255
    erase region 1: offset=0x1fe0000,size=0x8000,blocks=4
    RedBoot partition parsing not available
    Creating 6 MTD partitions on "86000000.flash":
    0x000000000000-0x000000100000 : "fpga"
    0x000000100000-0x000000140000 : "boot"
    0x000000140000-0x000000160000 : "bootenv"
    0x000000160000-0x000000180000 : "config"
    0x000000180000-0x000000b80000 : "image"
    0x000000b80000-0x000002000000 : "spare"
    Xilinx TEMAC MDIO: probed
    eth0: Dropping NETIF_F_SG since no checksum feature.
    TCP cubic registered
    NET: Registered protocol family 17
    uart_open(0) called
    ulite_startup ------------------------
    Freeing unused kernel memory: 11235k freed
    Mounting proc:
    Mounting var:
    Populating /var:
    Running local start scripts.
    Mounting sysfs:
    mdev: initialising /dev
    Mounting /etc/config:
    Populating /etc/config:
    flatfsd: Created 8 configuration files (168 bytes)
    Mounting devpnet eth0: Promiscuous mode disabled.
    ts:
    Setting hostname:
    Bringing up network interfaces:
    udhcpc (v1.14.3) started
    Sending discover...
    Sending seluart_open(0) called
    ect for 192.168.uart_close(0) called
    uart_open(0) called
    uart_flush_buffer(0) called

    Xilinx-SP605-LTP-full-WB-pc-msr-next-22-watch-wt-mdm login:




    Peter Korsgaard wrote:
    >>>>>> "Michal" == Michal Simek <monstr@monstr.eu> writes:
    >
    > Hi,
    >
    > Michal> The point is that clearing is called but there are still some
    > Michal> characters which are not printed. If you call that clearing you
    > Michal> just lost the part of log.
    >
    > Yes, but it shouldn't happen as __uart_wait_until_sent() is called
    > first.
    >
    > >> What is the problem here? Is it that the uart gets closed and reopened
    > >> (which causes ulite_startup() to get called)
    > Michal> while there's still data in
    > >> the uarts internal tx fifo (which then gets discarded)
    >
    > Michal> No data in internal tx fifo are not discarded.
    >
    > It is if ulite_startup is called.
    >
    > Michal> , or is it that
    > >> there's still data in the sw xmit circular buffer that isn't sent to the
    > >> hardware yet?
    >
    > Michal> yes, data are in the circ buffer head and tail are correctly setup and
    > Michal> because sending is slow that circ buffer clearing is called and head
    > Michal> and tail is zeroed.
    > Michal> I think the best solution will be to wait if head/tail is not the same
    > Michal> value which means there is data in circ buffer. Not sure if driver can
    > Michal> do anything with it or if there is any way how to delay buffer
    > Michal> clearing in the driver.
    >
    > I don't know much of the details of serial_core, but I believe
    > uart_close (and hence uart_circ_clear) is only called when all
    > characters in the circular buffer have been sent. What still might not
    > be sent is any data in the uart TX fifo, but __uart_wait_until_sent()
    > should handle that if you provide correct baudrate.
    >
    > >> What baudrate is your hardware running at? What baudrate have you
    > >> configured the kernel to use? Even though the uartlite itself doesn't do
    > >> anything with the baudrate setting (E.G. it is fixed in hardware), the
    > >> baudrate is used by the kernel to calculate timeouts (E.G. in
    > >> __uart_wait_until_sent and similar).
    >
    > Michal> It is the same style. You can't even setup baudrate in EDK. There is
    > Michal> no hardware connection through serial line. The whole communication is
    > Michal> done through jtag. I really don't know how fast xilinx can communicate
    > Michal> with mdm.
    >
    > Ok, does behaviour change if you set the kernel baudrate to something
    > really low (300bps or so)? Also don't forget to adjust your getty
    > settings!
    >


    --
    Michal Simek, Ing. (M.Eng)
    w: www.monstr.eu p: +42-0-721842854
    Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
    Microblaze U-BOOT custodian
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