linux-riscv.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: Ben Dooks <ben.dooks@codethink.co.uk>
To: Atish Patra <atishp@atishpatra.org>
Cc: devicetree@vger.kernel.org, Albert Ou <aou@eecs.berkeley.edu>,
	Cyril.Jean@microchip.com,
	Daire McNamara <daire.mcnamara@microchip.com>,
	Anup Patel <anup.patel@wdc.com>,
	"linux-kernel@vger.kernel.org List"
	<linux-kernel@vger.kernel.org>, Atish Patra <atish.patra@wdc.com>,
	Rob Herring <robh+dt@kernel.org>,
	Alistair Francis <alistair.francis@wdc.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	linux-riscv <linux-riscv@lists.infradead.org>,
	Padmarao Begari <padmarao.begari@microchip.com>
Subject: Re: [RFC PATCH 2/3] RISC-V: Initial DTS for Microchip ICICLE board
Date: Fri, 30 Oct 2020 21:19:41 +0000	[thread overview]
Message-ID: <2d7cc829-5df6-6b94-4c8f-9bae6080444e@codethink.co.uk> (raw)
In-Reply-To: <CAOnJCUJhQ=Zv0S4iCK4CDzQr_dfkw3J6ycdM=p6=5B2_sL1Ekg@mail.gmail.com>

On 30/10/2020 07:11, Atish Patra wrote:
> On Thu, Oct 29, 2020 at 3:24 AM Ben Dooks <ben.dooks@codethink.co.uk> wrote:
>>
>> On 28/10/2020 23:27, Atish Patra wrote:
>>> Add initial DTS for Microchip ICICLE board having only
>>> essential devcies (clocks, sdhci, ethernet, serial, etc).
>>>
>>> Signed-off-by: Atish Patra <atish.patra@wdc.com>
>>> ---
>>>    arch/riscv/boot/dts/Makefile                  |   1 +
>>>    arch/riscv/boot/dts/microchip/Makefile        |   2 +
>>>    .../microchip/microchip-icicle-kit-a000.dts   | 313 ++++++++++++++++++
>>>    3 files changed, 316 insertions(+)
>>>    create mode 100644 arch/riscv/boot/dts/microchip/Makefile
>>>    create mode 100644 arch/riscv/boot/dts/microchip/microchip-icicle-kit-a000.dts
>>>
>>> diff --git a/arch/riscv/boot/dts/Makefile b/arch/riscv/boot/dts/Makefile
>>> index ca1f8cbd78c0..3ea94ea0a18a 100644
>>> --- a/arch/riscv/boot/dts/Makefile
>>> +++ b/arch/riscv/boot/dts/Makefile
>>> @@ -1,5 +1,6 @@
>>>    # SPDX-License-Identifier: GPL-2.0
>>>    subdir-y += sifive
>>>    subdir-y += kendryte
>>> +subdir-y += microchip
>>>
>>>    obj-$(CONFIG_BUILTIN_DTB) := $(addsuffix /, $(subdir-y))
>>> diff --git a/arch/riscv/boot/dts/microchip/Makefile b/arch/riscv/boot/dts/microchip/Makefile
>>> new file mode 100644
>>> index 000000000000..55ad77521304
>>> --- /dev/null
>>> +++ b/arch/riscv/boot/dts/microchip/Makefile
>>> @@ -0,0 +1,2 @@
>>> +# SPDX-License-Identifier: GPL-2.0
>>> +dtb-$(CONFIG_SOC_MICROCHIP_POLARFIRE) += microchip-icicle-kit-a000.dtb
>>> diff --git a/arch/riscv/boot/dts/microchip/microchip-icicle-kit-a000.dts b/arch/riscv/boot/dts/microchip/microchip-icicle-kit-a000.dts
>>> new file mode 100644
>>> index 000000000000..5848920af55c
>>> --- /dev/null
>>> +++ b/arch/riscv/boot/dts/microchip/microchip-icicle-kit-a000.dts
>>> @@ -0,0 +1,313 @@
>>> +// SPDX-License-Identifier: GPL-2.0+
>>> +/* Copyright (c) 2020 Microchip Technology Inc */
>>> +
>>> +/dts-v1/;
>>> +
>>> +/* Clock frequency (in Hz) of the rtcclk */
>>> +#define RTCCLK_FREQ          1000000
>>> +
>>> +/ {
>>> +     #address-cells = <2>;
>>> +     #size-cells = <2>;
>>> +     model = "Microchip PolarFire-SoC";
>>> +     compatible = "microchip,polarfire-soc";
>>> +
>>> +     chosen {
>>> +             stdout-path = &serial0;
>>> +     };
>>> +
>>> +     cpus {
>>> +             #address-cells = <1>;
>>> +             #size-cells = <0>;
>>> +             timebase-frequency = <RTCCLK_FREQ>;
>>> +
>>> +             cpu@0 {
>>> +                     clock-frequency = <0>;
>>> +                     compatible = "sifive,rocket0", "riscv";
>>> +                     device_type = "cpu";
>>> +                     i-cache-block-size = <64>;
>>> +                     i-cache-sets = <128>;
>>> +                     i-cache-size = <16384>;
>>> +                     reg = <0>;
>>> +                     riscv,isa = "rv64imac";
>>> +                     status = "disabled";
>>> +
>>> +                     cpu0_intc: interrupt-controller {
>>> +                             #interrupt-cells = <1>;
>>> +                             compatible = "riscv,cpu-intc";
>>> +                             interrupt-controller;
>>> +                     };
>>> +             };
>>> +
>>> +             cpu@1 {
>>> +                     clock-frequency = <0>;
>>> +                     compatible = "sifive,rocket0", "riscv";
>>> +                     d-cache-block-size = <64>;
>>> +                     d-cache-sets = <64>;
>>> +                     d-cache-size = <32768>;
>>> +                     d-tlb-sets = <1>;
>>> +                     d-tlb-size = <32>;
>>> +                     device_type = "cpu";
>>> +                     i-cache-block-size = <64>;
>>> +                     i-cache-sets = <64>;
>>> +                     i-cache-size = <32768>;
>>> +                     i-tlb-sets = <1>;
>>> +                     i-tlb-size = <32>;
>>> +                     mmu-type = "riscv,sv39";
>>> +                     reg = <1>;
>>> +                     riscv,isa = "rv64imafdc";
>>> +                     tlb-split;
>>> +                     status = "okay";
>>> +
>>> +                     cpu1_intc: interrupt-controller {
>>> +                             #interrupt-cells = <1>;
>>> +                             compatible = "riscv,cpu-intc";
>>> +                             interrupt-controller;
>>> +                     };
>>> +             };
>>> +
>>> +             cpu@2 {
>>> +                     clock-frequency = <0>;
>>> +                     compatible = "sifive,rocket0", "riscv";
>>> +                     d-cache-block-size = <64>;
>>> +                     d-cache-sets = <64>;
>>> +                     d-cache-size = <32768>;
>>> +                     d-tlb-sets = <1>;
>>> +                     d-tlb-size = <32>;
>>> +                     device_type = "cpu";
>>> +                     i-cache-block-size = <64>;
>>> +                     i-cache-sets = <64>;
>>> +                     i-cache-size = <32768>;
>>> +                     i-tlb-sets = <1>;
>>> +                     i-tlb-size = <32>;
>>> +                     mmu-type = "riscv,sv39";
>>> +                     reg = <2>;
>>> +                     riscv,isa = "rv64imafdc";
>>> +                     tlb-split;
>>> +                     status = "okay";
>>> +
>>> +                     cpu2_intc: interrupt-controller {
>>> +                             #interrupt-cells = <1>;
>>> +                             compatible = "riscv,cpu-intc";
>>> +                             interrupt-controller;
>>> +                     };
>>> +             };
>>> +
>>> +             cpu@3 {
>>> +                     clock-frequency = <0>;
>>> +                     compatible = "sifive,rocket0", "riscv";
>>> +                     d-cache-block-size = <64>;
>>> +                     d-cache-sets = <64>;
>>> +                     d-cache-size = <32768>;
>>> +                     d-tlb-sets = <1>;
>>> +                     d-tlb-size = <32>;
>>> +                     device_type = "cpu";
>>> +                     i-cache-block-size = <64>;
>>> +                     i-cache-sets = <64>;
>>> +                     i-cache-size = <32768>;
>>> +                     i-tlb-sets = <1>;
>>> +                     i-tlb-size = <32>;
>>> +                     mmu-type = "riscv,sv39";
>>> +                     reg = <3>;
>>> +                     riscv,isa = "rv64imafdc";
>>> +                     tlb-split;
>>> +                     status = "okay";
>>> +
>>> +                     cpu3_intc: interrupt-controller {
>>> +                             #interrupt-cells = <1>;
>>> +                             compatible = "riscv,cpu-intc";
>>> +                             interrupt-controller;
>>> +                     };
>>> +             };
>>> +
>>> +             cpu@4 {
>>> +                     clock-frequency = <0>;
>>> +                     compatible = "sifive,rocket0", "riscv";
>>> +                     d-cache-block-size = <64>;
>>> +                     d-cache-sets = <64>;
>>> +                     d-cache-size = <32768>;
>>> +                     d-tlb-sets = <1>;
>>> +                     d-tlb-size = <32>;
>>> +                     device_type = "cpu";
>>> +                     i-cache-block-size = <64>;
>>> +                     i-cache-sets = <64>;
>>> +                     i-cache-size = <32768>;
>>> +                     i-tlb-sets = <1>;
>>> +                     i-tlb-size = <32>;
>>> +                     mmu-type = "riscv,sv39";
>>> +                     reg = <4>;
>>> +                     riscv,isa = "rv64imafdc";
>>> +                     tlb-split;
>>> +                     status = "okay";
>>> +                     cpu4_intc: interrupt-controller {
>>> +                             #interrupt-cells = <1>;
>>> +                             compatible = "riscv,cpu-intc";
>>> +                             interrupt-controller;
>>> +                     };
>>> +             };
>>> +     };
>>> +
>>> +     memory@80000000 {
>>> +             device_type = "memory";
>>> +             reg = <0x0 0x80000000 0x0 0x40000000>;
>>> +             clocks = <&clkcfg 26>;
>>> +     };
>>
>> U-boot doesn't seem to be updating this properly.
>>
>> The board should have 2GiB, confirmed by looking at the device's
>> chip markings. We only see 1GiB memory. The 0x80000000 bus window
>> is only capable of dealing with 1GiB memory. The higher 64-bit one
>> can have 16GiB mapped.
>>
>> Do we need a second node for the second GiB of memory?
>>
> We could just modify the reg size but to allow more memory. I tried
> that for Linux but it didn't boot.
> Probably, DDR init code in HSS only initialized 1GB of memory.

Yes, it is only looking at the low window which is 1GiB max.
If it used the upper window it would get the 16GiB.

I don't know how no-one noticed this issue before shipping a board
out with this. I have updated the firmware on my second board but
this only seems to currently fix a reboot issue with the eMMC.

>>> +
>>> +     soc {
>>> +             #address-cells = <2>;
>>> +             #size-cells = <2>;
>>> +             compatible = "simple-bus";
>>> +             ranges;
>>> +
>>> +             cache-controller@2010000 {
>>> +                     compatible = "sifive,fu540-c000-ccache", "cache";
>>> +                     cache-block-size = <64>;
>>> +                     cache-level = <2>;
>>> +                     cache-sets = <1024>;
>>> +                     cache-size = <2097152>;
>>> +                     cache-unified;
>>> +                     interrupt-parent = <&plic>;
>>> +                     interrupts = <1 2 3>;
>>> +                     reg = <0x0 0x2010000 0x0 0x1000>;
>>> +             };
>>> +
>>> +             clint@2000000 {
>>> +                     compatible = "riscv,clint0";
>>> +                     reg = <0x0 0x2000000 0x0 0xC000>;
>>> +                     interrupts-extended = <&cpu0_intc 3 &cpu0_intc 7
>>> +                                             &cpu1_intc 3 &cpu1_intc 7
>>> +                                             &cpu2_intc 3 &cpu2_intc 7
>>> +                                             &cpu3_intc 3 &cpu3_intc 7
>>> +                                             &cpu4_intc 3 &cpu4_intc 7>;
>>> +             };
>>> +
>>> +             plic: interrupt-controller@c000000 {
>>> +                     #interrupt-cells = <1>;
>>> +                     compatible = "sifive,plic-1.0.0";
>>> +                     reg = <0x0 0xc000000 0x0 0x4000000>;
>>> +                     riscv,ndev = <53>;
>>> +                     interrupt-controller;
>>> +                     interrupts-extended = <&cpu0_intc 11
>>> +                                     &cpu1_intc 11 &cpu1_intc 9
>>> +                                     &cpu2_intc 11 &cpu2_intc 9
>>> +                                     &cpu3_intc 11 &cpu3_intc 9
>>> +                                     &cpu4_intc 11 &cpu4_intc 9>;
>>> +             };
>>> +
>>> +             dma@3000000 {
>>> +                     compatible = "sifive,fu540-c000-pdma";
>>> +                     reg = <0x0 0x3000000 0x0 0x8000>;
>>> +                     interrupt-parent = <&plic>;
>>> +                     interrupts = <23 24 25 26 27 28 29 30>;
>>> +                     #dma-cells = <1>;
>>> +             };
>>> +
>>> +             refclk: refclk {
>>> +                     compatible = "fixed-clock";
>>> +                     #clock-cells = <0>;
>>> +                     clock-frequency = <600000000>;
>>> +                     clock-output-names = "msspllclk";
>>> +             };
>>> +
>>> +             clkcfg: clkcfg@20002000 {
>>> +                     compatible = "microchip,pfsoc-clkcfg";
>>> +                     reg = <0x0 0x20002000 0x0 0x1000>;
>>> +                     reg-names = "mss_sysreg";
>>> +                     clocks = <&refclk>;
>>> +                     #clock-cells = <1>;
>>> +                     clock-output-names = "cpuclk", "axiclk", "ahbclk", "ENVMclk", "MAC0clk", "MAC1clk", "MMCclk", "TIMERclk", "MMUART0clk", "MMUART1clk", "MMUART2clk", "MMUART3clk", "MMUART4clk", "SPI0clk", "SPI1clk", "I2C0clk", "I2C1clk", "CAN0clk", "CAN1clk", "USBclk", "RESERVED", "RTCclk", "QSPIclk", "GPIO0clk", "GPIO1clk", "GPIO2clk", "DDRCclk", "FIC0clk", "FIC1clk", "FIC2clk", "FIC3clk", "ATHENAclk", "CFMclk";
>>
>> Any chance of making this list multi-line, it is difficult to read as-is.
>>
> 
> Yes. We can also get rid of a few names that are not used. I will fix it in v2.
> 
>>> +             };
>>> +
>>> +             serial0: serial@20000000 {
>>> +                     compatible = "ns16550a";
>>> +                     reg = <0x0 0x20000000 0x0 0x400>;
>>> +                     reg-io-width = <4>;
>>> +                     reg-shift = <2>;
>>> +                     interrupt-parent = <&plic>;
>>> +                     interrupts = <90>;
>>> +                     current-speed = <115200>;
>>> +                     clocks = <&clkcfg 8>;
>>> +                     status = "okay";
>>> +             };
>>> +
>>> +             serial1: serial@20100000 {
>>> +                     compatible = "ns16550a";
>>> +                     reg = <0x0 0x20100000 0x0 0x400>;
>>> +                     reg-io-width = <4>;
>>> +                     reg-shift = <2>;
>>> +                     interrupt-parent = <&plic>;
>>> +                     interrupts = <91>;
>>> +                     current-speed = <115200>;
>>> +                     clocks = <&clkcfg 9>;
>>> +                     status = "okay";
>>> +             };
>>> +
>>> +             serial2: serial@20102000 {
>>> +                     compatible = "ns16550a";
>>> +                     reg = <0x0 0x20102000 0x0 0x400>;
>>> +                     reg-io-width = <4>;
>>> +                     reg-shift = <2>;
>>> +                     interrupt-parent = <&plic>;
>>> +                     interrupts = <92>;
>>> +                     current-speed = <115200>;
>>> +                     clocks = <&clkcfg 10>;
>>> +                     status = "okay";
>>> +             };
>>> +
>>> +             serial3: serial@20104000 {
>>> +                     compatible = "ns16550a";
>>> +                     reg = <0x0 0x20104000 0x0 0x400>;
>>> +                     reg-io-width = <4>;
>>> +                     reg-shift = <2>;
>>> +                     interrupt-parent = <&plic>;
>>> +                     interrupts = <93>;
>>> +                     current-speed = <115200>;
>>> +                     clocks = <&clkcfg 11>;
>>> +                     status = "okay";
>>> +             };
>>> +
>>> +             sdcard: sdhc@20008000 {
>>> +                     compatible = "cdns,sd4hc";
>>> +                     reg = <0x0 0x20008000 0x0 0x1000>;
>>> +                     interrupt-parent = <&plic>;
>>> +                     interrupts = <88>;
>>> +                     pinctrl-names = "default";
>>> +                     clocks = <&clkcfg 6>;
>>> +                     bus-width = <4>;
>>> +                     disable-wp;
>>> +                     no-1-8-v;
>>> +                     cap-mmc-highspeed;
>>> +                     cap-sd-highspeed;
>>> +                     card-detect-delay = <200>;
>>> +                     sd-uhs-sdr12;
>>> +                     sd-uhs-sdr25;
>>> +                     sd-uhs-sdr50;
>>> +                     sd-uhs-sdr104;
>>> +                     max-frequency = <200000000>;
>>> +                     status = "okay";
>>> +             };
>>
>> Given eMMC is the default device, shouldn't that be default for the
>> device tree too? Even if not, having the emmc node here would be a
>> good thing as it is different to the SD node.
>>
> 
> I tested this device tree with sdcard. That's why, I just picked the
> sdcard node.
> I am not sure if both eMMC & sdcard node can co-exist. The polar fire
> soc github repo
> seems to point that both of them have the same address and only 1 can be enabled
> at that time. That may not be true now as the github repo has not been
> updated in
> couple of months.
> 
> @Cyril : Can we enable both eMMC & sdcard at the same time ?

I would put /both/ in but only enable the one in use for the moment.
Our boards are booting of eMMC as supplied, so this isn't going to work 
as well. The eMMC is 8bit wide, and thus is only delivering 11MB/sec
instead of 22MB/sec. This performance is still not great, but losing
half the data-rate is just not good.

>>> +
>>> +             emac1: ethernet@20112000 {
>>> +                     compatible = "cdns,macb";
>>> +                     reg = <0x0 0x20112000 0x0 0x2000>;
>>> +                     interrupt-parent = <&plic>;
>>> +                     interrupts = <70 71 72 73>;
>>> +                     mac-address = [56 34 12 00 FC 00];
>>> +                     phy-mode = "sgmii";
>>> +                     clocks = <&clkcfg 5>, <&clkcfg 2>;
>>> +                     clock-names = "pclk", "hclk";
>>> +                     #address-cells = <1>;
>>> +                     #size-cells = <0>;
>>> +                     phy1: ethernet-phy@9 {
>>> +                             reg = <9>;
>>> +                             ti,fifo-depth = <0x01>;
>>> +                     };
>>> +             };
>>
>> Aren't there two ethernet ports on the board?
>>
> 
> Yes. I hadn't tested that out. I will test it and add the 2nd one as well.
> 
>> Also, at the moment u-boot is not filling the MAC address parameter
>> in so we've got at two boards on the network with the same MAC until
>> we override it in the device tree for the second.
>>
> 
> Looking at latest U-Boot patches, it seems it updates the mac address
> from the serial number.

Ok, the one supplied on the boards does not. And the boards /both/ have
the same MAC address!

>>> +
>>> +             uio_axi_lsram@2030000000 {
>>> +                     compatible = "generic-uio";
>>> +                     reg = <0x20 0x30000000 0 0x80000000 >;
>>> +                     status = "okay";
>>> +             };
>>> +     };
>>> +};
>>>
>>
>>
>> --
>> Ben Dooks                               http://www.codethink.co.uk/
>> Senior Engineer                         Codethink - Providing Genius
>>
>> https://www.codethink.co.uk/privacy.html
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv
> 
> 
> 


-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

https://www.codethink.co.uk/privacy.html

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  reply	other threads:[~2020-10-30 21:20 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-28 23:27 [RFC PATCH 0/3] Add Microchip PolarFire Soc Support Atish Patra
2020-10-28 23:27 ` [RFC PATCH 1/3] RISC-V: Add Microchip PolarFire SoC kconfig option Atish Patra
2020-10-30  9:08   ` Anup Patel
2020-11-03  9:55   ` Bin Meng
2020-11-06  7:14   ` Palmer Dabbelt
2020-10-28 23:27 ` [RFC PATCH 2/3] RISC-V: Initial DTS for Microchip ICICLE board Atish Patra
2020-10-29 10:24   ` Ben Dooks
2020-10-30  7:11     ` Atish Patra
2020-10-30 21:19       ` Ben Dooks [this message]
2020-11-03 15:07         ` Atish Patra
2020-11-03 15:19           ` Ben Dooks
2020-11-03 18:10           ` Cyril.Jean
2020-11-03 18:28             ` Ben Dooks
2020-11-03 18:36               ` Atish Patra
2020-11-03 18:39                 ` Ben Dooks
2020-11-03 18:45                   ` Atish Patra
2020-11-03 18:40               ` Cyril.Jean
2020-11-03 18:46                 ` Ben Dooks
2020-11-04  2:41     ` Bin Meng
2020-10-30  9:05   ` Anup Patel
2020-10-30 20:27     ` Atish Patra
2020-11-03 10:59       ` Ben Dooks
2020-11-03 15:08         ` Atish Patra
2020-10-30 21:20     ` Ben Dooks
2020-11-03 10:00     ` Bin Meng
2020-11-03 18:19       ` Cyril.Jean
2020-11-03 18:38         ` Atish Patra
2020-11-03 18:50           ` Cyril.Jean
2020-11-03 19:02             ` Atish Patra
2020-11-06  7:14   ` Palmer Dabbelt
2020-10-28 23:27 ` [RFC PATCH 3/3] RISC-V: Enable Microchip PolarFire ICICLE SoC Atish Patra
2020-10-30  9:09   ` Anup Patel
2020-10-30 21:21     ` Ben Dooks
2020-11-03 10:03   ` Bin Meng
2020-11-06  7:14   ` Palmer Dabbelt
2020-11-06  7:14 ` [RFC PATCH 0/3] Add Microchip PolarFire Soc Support Palmer Dabbelt
2020-11-06  7:37   ` Atish Patra
2020-11-06  8:11     ` Palmer Dabbelt

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=2d7cc829-5df6-6b94-4c8f-9bae6080444e@codethink.co.uk \
    --to=ben.dooks@codethink.co.uk \
    --cc=Cyril.Jean@microchip.com \
    --cc=alistair.francis@wdc.com \
    --cc=anup.patel@wdc.com \
    --cc=aou@eecs.berkeley.edu \
    --cc=atish.patra@wdc.com \
    --cc=atishp@atishpatra.org \
    --cc=daire.mcnamara@microchip.com \
    --cc=devicetree@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=padmarao.begari@microchip.com \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    --cc=robh+dt@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).