dtb_overlay vs uboot_overlay_addr

[kugelbit]

Hey,

We are working on cape for our beaglebone. For our cape we have this overlay:

/dts-v1/;
/plugin/;

/ {
   compatible = "ti,beaglebone", "ti,beaglebone-black";

   part-number = "BB-SHPRD";
   version = "00A0";

   /* This overlay uses the following resources */
   exclusive-use =
        "P8.11", /* DEBUG PIN1 PRU0 */
        "P8.12", /* LED1 PRU0 */
        "P8.13", /* ENABLE HARVESTER */
        "P8.28", /* ADC RST/PDN */
        "P8.30", /* LED2 USER SPACE */
        "P8.33", /* GENERAL PURPOSE BUTTON */
        "P8.34", /* GENERAL PURPOSE LED */
        "P8.36", /* ENABLE LEVEL CONVERTER */
        "P8.41", /* DEBUG PIN0 PRU1 */
        "P8.42", /* DEBUG PIN1 PRU1 */
        "P8.43", /* TARGET GPIO2 */
        "P8.44", /* TARGET GPIO3 */
        "P8.45", /* TARGET GPIO0 */
        "P8.46", /* TARGET GPIO1 */
        "P9.11", /* ENABLE MPPT# */
        "P9.12", /* ENABLE V ANALOG */
        "P9.15", /* SELECT LOAD*/
        "P9.16", /* ENABLE V FIXED*/
        "P9.25", /* SPI CS ADC */
        "P9.27", /* SPI MISO */
        "P9.28", /* SPI SCLK */
        "P9.29", /* DEBUG PIN0 PRU0 */
        "P9.30", /* SPI MOSI */
        "P9.31", /* SPI CS DAC */
        "P9.41", /* SWDIO */
        "P9.42", /* SWDCLK */
        "pru0",
        "pru1";
   /* Check Table 9-60 in am335x TRM */


   fragment@0 {
      target = <&am33xx_pinmux>;
      __overlay__ {
         bb_shprd_pins: pinmux_bb_shprd_pins {
            pinctrl-single,pins = <
            0x034 0x06  /* P8.11, pr1_pru0_pru_r30_15 */
            0x030 0x06  /* P8.12, pr1_pru0_pru_r30_14 */
            0x024 0x07  /* P8.13, gpio0[23] */
            0x0e8 0x07	/* P8.28, gpio2[24] */
            0x0ec 0x07	/* P8.30, gpio2[25] */
            0x0d4 0x37	/* P8.33, gpio0[9] */
            0x0cc 0x07	/* P8.34, gpio2[17] */
            0x0c8 0x07	/* P8.36, gpio2[16] */
            0x0b0 0x05	/* P8.41, pr1_pru1_pru_r30_4 */
            0x0b4 0x05	/* P8.42, pr1_pru1_pru_r30_5 */
            0x0a8 0x26	/* P8.43, pr1_pru1_pru_r31_2 */
            0x0ac 0x26	/* P8.44, pr1_pru1_pru_r31_3 */
            0x0a0 0x26	/* P8.45, pr1_pru1_pru_r31_0 */
            0x0a4 0x26	/* P8.46, pr1_pru1_pru_r31_1 */

            0x070 0x07	/* P9_11, gpio0[30] */
            0x078 0x07	/* P9_12, gpio1[28] */
            0x040 0x07	/* P9_15, gpio1[16] */
            0x04c 0x07	/* P9_16, gpio1[19] */
            0x1ac 0x05	/* P9_25, pr1_pru0_pru_r30_7 */
            0x1a4 0x26	/* P9_27, pr1_pru0_pru_r31_5 */
            0x19c 0x05	/* P9_28, pr1_pru0_pru_r30_3 */
            0x194 0x05	/* P9_28, pr1_pru0_pru_r30_1 */
            0x198 0x05	/* P9_30, pr1_pru0_pru_r30_2 */
            0x190 0x05	/* P9_31, pr1_pru0_pru_r30_0 */
            0x1a8 0x27	/* P9_41B, gpio3[20] */
            0x1a0 0x07	/* P9_42B, gpio3[18] */
            >;
         };
      };
   };

   fragment@1 {
       target = <&pruss>;
       __overlay__ {
           status = "okay";
            pinctrl-names = "default";
            pinctrl-0 = <&bb_shprd_pins>;
            shepherd{
               compatible = "shepherd";
               prusses = <&pruss>;
            };	
       };
   };

};

After installing the overlay there are 2 different options to load it.

1. Option:
   You can specify the overlay in the uEnv.txt under an uboot_overlay_addr tag like this:

uboot_overlay_addr5=/lib/firmware/BB-SHPRD-00A0.dtbo

2. Option:
   the second option is the specify the overlay in the uEnv.txt under the dtb_overlay tag like this:

dtb_overlay=/lib/firmware/BB-SHPRD-00A0.dtbo

My first questions are: What is the difference between this two options? - Is there another option?

We found out that there is some strange behavior, if we use option 1.
In fragment@1 we have our own shepherd overlay struct for pruss. In this struct we define a kind of pointer to the pruss: prusses = <&pruss>;.

If we use option 2 this pointer will be set correct:
/proc/device-tree/ocp/pruss_soc_bus@4a326004/pruss@0/shepherd/prusses
correspond to
/proc/device-tree/ocp/pruss_soc_bus@4a326004/pruss@0/phandle

If we use option 1 this pointer will be not set correct and points to no where...

My conclusion is that there must be an difference between loading overlays with dtb_overlay and uboot_overlay_addr. Could it be a problem with the load-order of the overlays? We manipulate the pruss device-tree part, so i guess the /lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo overlay must be loaded before our custom overlay?

Why there are two different option for loading overlays? Can i load more than one overlay with the dtb_overlay option? What is the best practice to load more than one custom overlay?

Here some additional Information:

uEnv.txt (option ):

#Docs: http://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0

uname_r=4.14.108-ti-r104
#uuid=
#dtb=

###U-Boot Overlays###
###Documentation: http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays
###Master Enable
enable_uboot_overlays=1
###
###Overide capes with eeprom
uboot_overlay_addr0=/lib/firmware/BB-UART1-00A0.dtbo
###
###Additional custom capes
uboot_overlay_addr4=/lib/firmware/BB-I2C1-00A0.dtbo
#uboot_overlay_add5=/lib/firmware/BB-SHPRD-00A0.dtbo # option 1
uboot_overlay_addr6=/lib/firmware/DD-GPS-00A0.dtbo

###Custom Cape
dtb_overlay=/lib/firmware/BB-SHPRD-00A0.dtbo # option 2
#dtb_overlay=/lib/firmware/DD-GPS-00A0.dtbo


###Disable auto loading of virtual capes (emmc/video/wireless/adc)                                                                                 
disable_uboot_overlay_video=1
disable_uboot_overlay_audio=1
disable_uboot_overlay_wireless=1
#disable_uboot_overlay_adc=1

###
###PRUSS OPTIONS
###pru_rproc (4.4.x-ti kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-4-TI-00A0.dtbo
###pru_rproc (4.14.x-ti kernel)
uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo
###pru_rproc (4.19.x-ti kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-19-TI-00A0.dtbo
###pru_uio (4.4.x-ti, 4.14.x-ti, 4.19.x-ti & mainline/bone kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-UIO-00A0.dtbo
###

###Cape Universal Enable
#enable_uboot_cape_universal=1
#cape_enable=bone_capemgr.enable_partno=DD-GPS,BB-SHPRD,UART1,I2C1
#capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN


cmdline=coherent_pool=1M net.ifnames=0 quiet cape_universal=enable

sudo /opt/scripts/tools/version.sh (option 1):

git:/opt/scripts/:[9df8deb6b2ae7570c9102ab58f795d3bed592194]
eeprom:[A335BNLTBBG1BBG219014639]
model:[TI_AM335x_BeagleBone_Green]
dogtag:[rcn-ee.net console Ubuntu Image 2019-04-10]
bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot 2019.01-00002-g6de8c74429]:[location: dd MBR]
kernel:[4.14.108-ti-r104]
uboot_overlay_options:[enable_uboot_overlays=1]
uboot_overlay_options:[uboot_overlay_addr0=/lib/firmware/BB-UART1-00A0.dtbo]
uboot_overlay_options:[uboot_overlay_addr1=/lib/firmware/BB-I2C1-00A0.dtbo]
uboot_overlay_options:[uboot_overlay_addr2=/lib/firmware/DD-GPS-00A0.dtbo]
uboot_overlay_options:[uboot_overlay_addr5=/lib/firmware/BB-SHPRD-00A0.dtbo]
uboot_overlay_options:[disable_uboot_overlay_emmc=1]
uboot_overlay_options:[disable_uboot_overlay_video=1]
uboot_overlay_options:[disable_uboot_overlay_audio=1]
uboot_overlay_options:[disable_uboot_overlay_wireless=1]
uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo]
pkg check: to individually upgrade run: [sudo apt install --only-upgrade <pkg>]
pkg:[bb-cape-overlays]:[4.4.20190922.0-0rcnee0~bionic+20190922]
pkg:[bb-wl18xx-firmware]:[1.20190227.1-0rcnee0~bionic+20190227]
pkg:[kmod]:[24-1ubuntu3.2rcnee0~bionic+20190208]
WARNING:pkg:[librobotcontrol]:[NOT_INSTALLED]
groups:[ubuntu : ubuntu adm kmem dialout cdrom floppy audio dip video plugdev users systemd-journal bluetooth netdev i2c gpio pwm eqep admin spi tisdk weston-launch xenomai cloud9ide]
cmdline:[console=ttyO0,115200n8 bone_capemgr.uboot_capemgr_enabled=1 root=/dev/mmcblk0p1 ro rootfstype=ext4 rootwait coherent_pool=1M net.ifnames=0 quiet cape_universal=enable]
dmesg | grep remote
[    1.236692] remoteproc remoteproc0: wkup_m3 is available
[    1.317856] remoteproc remoteproc0: powering up wkup_m3
[    1.317973] remoteproc remoteproc0: Booting fw image am335x-pm-firmware.elf, size 217168
[    1.321938] remoteproc remoteproc0: remote processor wkup_m3 is now up
[   29.279359] remoteproc remoteproc1: 4a334000.pru is available
[   29.289274] remoteproc remoteproc2: 4a338000.pru is available
dmesg | grep pru
[   28.972869] pruss 4a300000.pruss: creating PRU cores and other child platform devices
[   29.279359] remoteproc remoteproc1: 4a334000.pru is available
[   29.282237] pru-rproc 4a334000.pru: PRU rproc node /ocp/pruss_soc_bus@4a326004/pruss@0/pru@34000 probed successfully
[   29.289274] remoteproc remoteproc2: 4a338000.pru is available
[   29.289403] pru-rproc 4a338000.pru: PRU rproc node /ocp/pruss_soc_bus@4a326004/pruss@0/pru@38000 probed successfully
dmesg | grep pinctrl-single
[    1.040274] pinctrl-single 44e10800.pinmux: 142 pins at pa f9e10800 size 568
dmesg | grep gpio-of-helper
[    1.041492] gpio-of-helper ocp:cape-universal: ready
lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
END

sudo /opt/scripts/tools/version.sh (option 2):

git:/opt/scripts/:[9df8deb6b2ae7570c9102ab58f795d3bed592194]
eeprom:[A335BNLTBBG1BBG219014639]
model:[TI_AM335x_BeagleBone_Green]
dogtag:[rcn-ee.net console Ubuntu Image 2019-04-10]
bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot 2019.01-00002-g6de8c74429]:[location: dd MBR]
kernel:[4.14.108-ti-r104]
uboot_overlay_options:[enable_uboot_overlays=1]
uboot_overlay_options:[uboot_overlay_addr0=/lib/firmware/BB-UART1-00A0.dtbo]
uboot_overlay_options:[uboot_overlay_addr1=/lib/firmware/BB-I2C1-00A0.dtbo]
uboot_overlay_options:[uboot_overlay_addr2=/lib/firmware/DD-GPS-00A0.dtbo]
uboot_overlay_options:[disable_uboot_overlay_emmc=1]
uboot_overlay_options:[disable_uboot_overlay_video=1]
uboot_overlay_options:[disable_uboot_overlay_audio=1]
uboot_overlay_options:[disable_uboot_overlay_wireless=1]
uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo]
uboot_overlay_options:[dtb_overlay=/lib/firmware/BB-SHPRD-00A0.dtbo]
pkg check: to individually upgrade run: [sudo apt install --only-upgrade <pkg>]
pkg:[bb-cape-overlays]:[4.4.20190922.0-0rcnee0~bionic+20190922]
pkg:[bb-wl18xx-firmware]:[1.20190227.1-0rcnee0~bionic+20190227]
pkg:[kmod]:[24-1ubuntu3.2rcnee0~bionic+20190208]
WARNING:pkg:[librobotcontrol]:[NOT_INSTALLED]
groups:[ubuntu : ubuntu adm kmem dialout cdrom floppy audio dip video plugdev users systemd-journal bluetooth netdev i2c gpio pwm eqep admin spi tisdk weston-launch xenomai cloud9ide]
cmdline:[console=ttyO0,115200n8 bone_capemgr.uboot_capemgr_enabled=1 root=/dev/mmcblk0p1 ro rootfstype=ext4 rootwait coherent_pool=1M net.ifnames=0 quiet cape_universal=enable]
dmesg | grep remote
[    1.236704] remoteproc remoteproc0: wkup_m3 is available
[    1.317855] remoteproc remoteproc0: powering up wkup_m3
[    1.317977] remoteproc remoteproc0: Booting fw image am335x-pm-firmware.elf, size 217168
[    1.321932] remoteproc remoteproc0: remote processor wkup_m3 is now up
[   30.443757] remoteproc remoteproc1: 4a334000.pru is available
[   30.457269] remoteproc remoteproc2: 4a338000.pru is available
dmesg | grep pru
[   30.162098] pruss 4a300000.pruss: creating PRU cores and other child platform devices
[   30.443757] remoteproc remoteproc1: 4a334000.pru is available
[   30.443880] pru-rproc 4a334000.pru: PRU rproc node /ocp/pruss_soc_bus@4a326004/pruss@0/pru@34000 probed successfully
[   30.457269] remoteproc remoteproc2: 4a338000.pru is available
[   30.457393] pru-rproc 4a338000.pru: PRU rproc node /ocp/pruss_soc_bus@4a326004/pruss@0/pru@38000 probed successfully
dmesg | grep pinctrl-single
[    1.040281] pinctrl-single 44e10800.pinmux: 142 pins at pa f9e10800 size 568
dmesg | grep gpio-of-helper
[    1.041493] gpio-of-helper ocp:cape-universal: ready
lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
END

[mvduin]

I don't know if your ubuntu system is different but in U-Boot 2019.04-00002-g07d5700e21 used in the official beagleboard.org Debian Buster 2020-04-06 images, the order of overlays is:

• hardware-specific fixup overlay (M-BB-*) if applicable
• ADC overlay, if not disabled
• uboot_overlay_addr0..3 if set manually or by cape autodetection, and not disabled
• uboot_overlay_addr4..7 if set manually
• eMMC overlay if applicable and not disabled
• HDMI overlay if applicable and not disabled
  • (selection of HDMI overlay also influenced by disable_uboot_overlay_audio)
• Wireless overlay if applicable and not disabled
• uboot_overlay_pru if set manually
• uboot_overlay_pru_add if set manually
• dtb_overlay if set manually
• universal overlay (univ-*) if applicable and enabled

So yes, dtb_overlay is able to reference nodes created by uboot_overlay_pru while uboot_overlay_addr4..7 can not. I'm not completely sure why this goes wrong though since the &pruss node isn't created by the overlay, it already exists in the base dtb. I'm guessing u-boot gets confused by the redefinition of the &pruss label by AM335X-PRU-RPROC-4-14-TI-00A0, even though it's being redefined to point to the exact same node it used to. In that case the problem would also be fixed by trimming the AM335X-PRU-RPROC-4-14-TI-00A0 overlay to something like:

/dts-v1/;
/plugin/;

/*
 * Helper to show loaded overlays under: /proc/device-tree/chosen/overlays/
 */
&{/chosen} {
	overlays {
		AM335X-PRU-RPROC-4-14-TI-00A0 = __TIMESTAMP__;
	};
};

/ {
	fragment@1 {
		target = <&pruss_soc_bus>;
		__overlay__ {
			status = "okay";

			shmem@0 {
				reg = <0x0 0x2000>,
				      <0x2000 0x2000>,
				      <0x10000 0x3000>;
				reg-names = "dram0",
					    "dram1",
					    "dram2";
				compatible = "uio";
				symlink = "uio/pru-shmem";
			};
		};
	};

	fragment@2 {
		target = <&pruss>;
		__overlay__ {
			status = "okay";
		};
	};
};