[PATCH] ARM: DTS: make rpi3/4 use pl011 uart as primary
Ahmad Fatoum
a.fatoum at pengutronix.de
Wed Jun 15 01:24:59 PDT 2022
Hello Daniel,
On 11.06.22 20:28, Daniel Brát wrote:
> When the videocore first-stage bootloader finds 'dtoverlay=disable-bt' in the
> 'config.txt', asides from applying said overlay, it also disables fixed
> clock for the vpu, which miniuart requires to calculate correct baudrate,
> rendering it non-functional. This can be fixed by adding 'core_freq=250'
> to the config, but since barebox has drivers for the pl011 full-fledged UART,
> lets just make barebox use it instead.
For me on the Raspberry Pi 4 64-bit, boot rpi is now silent
with this patch applied.
I have
enable_uart=1
uart_2ndstage=1
arm_64bit=1
[pi4]
arm_boost=1
in my config.txt. Boot log below. Any ideas?
Booting entry 'rpi'
Adding "earlycon=pl011,0xfe201000,115200n8" to Kernel commandline
Loading GZIP compressed '/boot/kernel8.img'
Adding "earlycon=pl011,0xfe201000,115200n8" to Kernel commandline
Loading ARM aarch64 Linux image '/tmp/bootm-compressed-6504dc00'
Loading devicetree from '/vc.dtb'
commandline: earlycon=pl011,0xfe201000,115200n8 coherent_pool=1M 8250.nr_uarts=1 snd_bcm2835.enable_compat_alsa=0 snd_bcm2835.enable_hdmi=1 smsc95xx.macaddr=DC:A6:32:44:7E:4C vc_mem.mem_base=0x3ec00000 vc_mem.mem_size=0x40000000 console=ttyS0,115200 console=tty1 root=PARTUUID=286db7ac-02 rootfstype=ext4 fsck.repair=yes rootwait
Loaded kernel to 0x00200000, devicetree at 0x017f0000
[ 0.000000] Booting Linux on physical CPU 0x0000000000 [0x410fd083]
[ 0.000000] Linux version 5.15.32-v8+ (dom at buildbot) (aarch64-linux-gnu-gcc-8 (Ubuntu/Linaro 8.4.0-3ubuntu1) 8.4.0, GNU ld (GNU Binutils for Ubuntu) 2.34) #1538 SMP PREEMPT Thu Mar 31 19:40:39 BST 2022
[ 0.000000] random: fast init done
[ 0.000000] Machine model: Raspberry Pi 4 Model B Rev 1.1
[ 0.000000] earlycon: pl11 at MMIO 0x00000000fe201000 (options '115200n8')
[ 0.000000] printk: bootconsole [pl11] enabled
[ 0.000000] efi: UEFI not found.
[ 0.000000] Reserved memory: created CMA memory pool at 0x000000000ac00000, size 320 MiB
[ 0.000000] OF: reserved mem: initialized node linux,cma, compatible id shared-dma-pool
[ 0.000000] Zone ranges:
[ 0.000000] DMA [mem 0x0000000000000000-0x000000003b3fffff]
[ 0.000000] DMA32 empty
[ 0.000000] Normal empty
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000000000000-0x000000003b3fffff]
[ 0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x000000003b3fffff]
[ 0.000000] percpu: Embedded 28 pages/cpu s77144 r8192 d29352 u114688
[ 0.000000] Detected PIPT I-cache on CPU0
[ 0.000000] CPU features: detected: Spectre-v2
[ 0.000000] CPU features: detected: Spectre-v4
[ 0.000000] CPU features: detected: Spectre-BHB
[ 0.000000] CPU features: detected: ARM errata 1165522, 1319367, or 1530923
[ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 238896
[ 0.000000] Kernel command line: earlycon=pl011,0xfe201000,115200n8 coherent_pool=1M 8250.nr_uarts=1 snd_bcm2835.enable_compat_alsa=0 snd_bcm2835.enable_hdmi=1 smsc95xx.macaddr=DC:A6:32:44:7E:4C vc_mem.mem_base=0x3ec00000 vc_mem.mem_size=0x40000000 console=ttyS0,115200 console=tty1 root=PARTUUID=286db7ac-02 rootfstype=ext4 fsck.repair=yes rootwait
[ 0.000000] Dentry cache hash table entries: 131072 (order: 8, 1048576 bytes, linear)
[ 0.000000] Inode-cache hash table entries: 65536 (order: 7, 524288 bytes, linear)
[ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[ 0.000000] Memory: 599928K/970752K available (11456K kernel code, 1962K rwdata, 4144K rodata, 3776K init, 964K bss, 43144K reserved, 327680K cma-reserved)
[ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[ 0.000000] ftrace: allocating 37889 entries in 149 pages
[ 0.000000] ftrace: allocated 149 pages with 4 groups
[ 0.000000] trace event string verifier disabled
[ 0.000000] rcu: Preemptible hierarchical RCU implementation.
[ 0.000000] rcu: RCU event tracing is enabled.
[ 0.000000] rcu: RCU restricting CPUs from NR_CPUS=256 to nr_cpu_ids=4.
[ 0.000000] Trampoline variant of Tasks RCU enabled.
[ 0.000000] Rude variant of Tasks RCU enabled.
[ 0.000000] Tracing variant of Tasks RCU enabled.
[ 0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies.
[ 0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=4
[ 0.000000] NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
[ 0.000000] Root IRQ handler: gic_handle_irq
[ 0.000000] GIC: Using split EOI/Deactivate mode
[ 0.000000] irq_brcmstb_l2: registered L2 intc (/soc/interrupt-controller at 7ef00100, parent irq: 10)
[ 0.000000] random: get_random_bytes called from start_kernel+0x510/0x6f8 with crng_init=1
[ 0.000000] arch_timer: cp15 timer(s) running at 54.00MHz (phys).
[ 0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0xc743ce346, max_idle_ns: 440795203123 ns
[ 0.000001] sched_clock: 56 bits at 54MHz, resolution 18ns, wraps every 4398046511102ns
[ 0.008323] Console: colour dummy device 80x25
[ 0.012819] printk: console [tty1] enabled
[ 0.016958] printk: bootconsole [pl11] disabled
> Signed-off-by: Daniel Brát <danek.brat at gmail.com>
> ---
> arch/arm/dts/bcm2711-rpi-4.dts | 8 +-------
> arch/arm/dts/bcm2837-rpi-3.dts | 2 ++
> arch/arm/dts/rpi-use-pl011-uart.dtsi | 24 ++++++++++++++++++++++++
> 3 files changed, 27 insertions(+), 7 deletions(-)
> create mode 100644 arch/arm/dts/rpi-use-pl011-uart.dtsi
>
> diff --git a/arch/arm/dts/bcm2711-rpi-4.dts b/arch/arm/dts/bcm2711-rpi-4.dts
> index 3c0caa73f..e082ad868 100644
> --- a/arch/arm/dts/bcm2711-rpi-4.dts
> +++ b/arch/arm/dts/bcm2711-rpi-4.dts
> @@ -9,10 +9,4 @@
> status = "disabled";
> };
>
> -&uart1 {
> - /* VPU core clock is reported at 200MHz, but needs to be 500Mhz
> - * for ns16550 driver to set correct baudrate. Until that's
> - * figured out, hardcode clock frequency to the expected value
> - */
> - clock-frequency = <500000000>;
> -};
> +#include "rpi-use-pl011-uart.dtsi"
> diff --git a/arch/arm/dts/bcm2837-rpi-3.dts b/arch/arm/dts/bcm2837-rpi-3.dts
> index e82d518fa..6af9e9d7c 100644
> --- a/arch/arm/dts/bcm2837-rpi-3.dts
> +++ b/arch/arm/dts/bcm2837-rpi-3.dts
> @@ -7,3 +7,5 @@
> &sdhci {
> status = "disabled";
> };
> +
> +#include "rpi-use-pl011-uart.dtsi"
> diff --git a/arch/arm/dts/rpi-use-pl011-uart.dtsi b/arch/arm/dts/rpi-use-pl011-uart.dtsi
> new file mode 100644
> index 000000000..7c75b07f8
> --- /dev/null
> +++ b/arch/arm/dts/rpi-use-pl011-uart.dtsi
> @@ -0,0 +1,24 @@
> +/* https://www.raspberrypi.com/documentation/computers/configuration.html#primary-and-secondary-uart */
> +
> +/* Makes barebox use pl011 uart as primary */
> +
> +&uart1 {
> + status = "disabled";
> +};
> +
> +&uart0 {
> + pinctrl-names = "default";
> + pinctrl-0 = <&uart0_gpio14>;
> + status = "okay";
> +};
> +
> +/delete-node/ &bt;
> +
> +&{/aliases} {
> + serial0 = &uart0;
> + serial1 = &uart1;
> +};
> +
> +&{/chosen} {
> + stdout-path = "/serial0:115200n8";
> +};
--
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