Microzed issues

List

[CLEARED] UART

Description:
    UART register contents: timeout=0 rxfifo_level=56, should be timeout=10 rxfifo_level=56
    minicom prints 56 symbols at a time when rxfifo reaches its level.
    remembers all typed symbols
    sometimes the timeout register is set correctly
Possible reason:
    In driver .startup and .termios conflict? Racing Resets or reset takes time?
Solution:
    Added a delay after reset - some other functions in the driver also have it - some not. Luck?
Patch:
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index f214c7f..164e32d 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -704,6 +704,9 @@ static void cdns_uart_set_termios(struct uart_port *port,
        ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST;
        cdns_uart_writel(ctrl_reg, CDNS_UART_CR_OFFSET);
 
+       while (cdns_uart_readl(CDNS_UART_CR_OFFSET) &
+                       (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST))
+               cpu_relax();
        /*
         * Clear the RX disable and TX disable bits and then set the TX enable
         * bit and RX enable bit to enable the transmitter and receiver.
Links:
    * https://forums.xilinx.com/t5/Zynq-All-Programmable-SoC/Zynq-Uart-timeout-problem/td-p/432016
    * http://www.makelinux.net/ldd3/chp-7-sect-3

[CLEARED] SSH terminal

Description:
    Freezes, lags but remembers all typed symbols
Possible reason:
    Devices with identical MACs in LAN

RTC

Description:
    Not an issue
    3x"hwclock: can't open '/dev/misc/rtc': No such file or directory" in boot log
Possible reason:
    a. Microzed doesn't have a real-time clock (rtc)
    b. Reported by /etc/init.d/hwclock.sh - not the driver

U-boot Falcon mode (boot from SPL directly to OS avoiding full u-boot)

Description:
    Try
Possible reason:
    

U-boot spl reads u-boot-dtb.img 2 times

Description:
    Not an issue - prints "reading u-boot-dtb.img" 2 times. "Very Annoying","Every microsecond counts"!
Possible reason:
    u-boot/common/spl/spl_fat.c:
        int spl_load_image_fat(block_dev_desc_t *block_dev,
        						int partition,
        						const char *filename)
        {
        	int err;
        	struct image_header *header;
        	
        	err = spl_register_fat_device(block_dev, partition);
        	if (err)
        		goto end;
        
        	header = (struct image_header *)(CONFIG_SYS_TEXT_BASE -
        						sizeof(struct image_header));
        
        	err = file_fat_read(filename, header, sizeof(struct image_header));
        	if (err <= 0)
        		goto end;
        
        	spl_parse_image_header(header);
        
        	err = file_fat_read(filename, (u8 *)spl_image.load_addr, 0);
        
        end:
        #ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
        	if (err <= 0)
        		printf("%s: error reading image %s, err - %d\n",
        		       __func__, filename, err);
        #endif
        
        	return (err <= 0);
        }

Useful pages

• http://processors.wiki.ti.com/index.php/Enabling_Stack_Dumping_in_Linux_Kernel
• https://lists.yoctoproject.org/pipermail/poky/2015-February/010037.html - change hostname in poky
• http://www.makelinux.net/ldd3/chp-7-sect-3
• http://www.denx.de/wiki/pub/U-Boot/MiniSummitELCE2013/2013-ELCE-U-Boot-Falcon-Boot.pdf