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([2a01:e0a:982:cbb0:5e59:c27b:747a:3f52]) by smtp.gmail.com with ESMTPSA id a9-20020a05600c224900b003fef5402d2dsm13238123wmm.8.2023.08.28.00.58.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 28 Aug 2023 00:58:47 -0700 (PDT) Message-ID: Date: Mon, 28 Aug 2023 09:58:48 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Neil Armstrong Reply-To: neil.armstrong@linaro.org Subject: Re: [PATCH v2] Revert "tty: serial: meson: Add a earlycon for the T7 SoC" Content-Language: en-US, fr To: Lucas Tanure , Greg Kroah-Hartman , Jiri Slaby , Kevin Hilman Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org References: <20230827082944.5100-1-tanure@linux.com> <7bf9e716-0ff2-56d5-07ab-db027901454e@linaro.org> <09735262-1bc0-40cf-b139-22cccf70bcab@linux.com> <8d2ba0d3-55eb-45cf-b88a-bafef35e96b9@linux.com> Autocrypt: addr=neil.armstrong@linaro.org; keydata= xsBNBE1ZBs8BCAD78xVLsXPwV/2qQx2FaO/7mhWL0Qodw8UcQJnkrWmgTFRobtTWxuRx8WWP GTjuhvbleoQ5Cxjr+v+1ARGCH46MxFP5DwauzPekwJUD5QKZlaw/bURTLmS2id5wWi3lqVH4 BVF2WzvGyyeV1o4RTCYDnZ9VLLylJ9bneEaIs/7cjCEbipGGFlfIML3sfqnIvMAxIMZrvcl9 qPV2k+KQ7q+aXavU5W+yLNn7QtXUB530Zlk/d2ETgzQ5FLYYnUDAaRl+8JUTjc0CNOTpCeik 80TZcE6f8M76Xa6yU8VcNko94Ck7iB4vj70q76P/J7kt98hklrr85/3NU3oti3nrIHmHABEB AAHNKk5laWwgQXJtc3Ryb25nIDxuZWlsLmFybXN0cm9uZ0BsaW5hcm8ub3JnPsLAkQQTAQoA OwIbIwULCQgHAwUVCgkICwUWAgMBAAIeAQIXgBYhBInsPQWERiF0UPIoSBaat7Gkz/iuBQJk Q5wSAhkBAAoJEBaat7Gkz/iuyhMIANiD94qDtUTJRfEW6GwXmtKWwl/mvqQtaTtZID2dos04 YqBbshiJbejgVJjy+HODcNUIKBB3PSLaln4ltdsV73SBcwUNdzebfKspAQunCM22Mn6FBIxQ GizsMLcP/0FX4en9NaKGfK6ZdKK6kN1GR9YffMJd2P08EO8mHowmSRe/ExAODhAs9W7XXExw UNCY4pVJyRPpEhv373vvff60bHxc1k/FF9WaPscMt7hlkbFLUs85kHtQAmr8pV5Hy9ezsSRa GzJmiVclkPc2BY592IGBXRDQ38urXeM4nfhhvqA50b/nAEXc6FzqgXqDkEIwR66/Gbp0t3+r yQzpKRyQif3OwE0ETVkGzwEIALyKDN/OGURaHBVzwjgYq+ZtifvekdrSNl8TIDH8g1xicBYp QTbPn6bbSZbdvfeQPNCcD4/EhXZuhQXMcoJsQQQnO4vwVULmPGgtGf8PVc7dxKOeta+qUh6+ SRh3vIcAUFHDT3f/Zdspz+e2E0hPV2hiSvICLk11qO6cyJE13zeNFoeY3ggrKY+IzbFomIZY 4yG6xI99NIPEVE9lNBXBKIlewIyVlkOaYvJWSV+p5gdJXOvScNN1epm5YHmf9aE2ZjnqZGoM Mtsyw18YoX9BqMFInxqYQQ3j/HpVgTSvmo5ea5qQDDUaCsaTf8UeDcwYOtgI8iL4oHcsGtUX oUk33HEAEQEAAcLAXwQYAQIACQUCTVkGzwIbDAAKCRAWmrexpM/4rrXiB/sGbkQ6itMrAIfn M7IbRuiSZS1unlySUVYu3SD6YBYnNi3G5EpbwfBNuT3H8//rVvtOFK4OD8cRYkxXRQmTvqa3 3eDIHu/zr1HMKErm+2SD6PO9umRef8V82o2oaCLvf4WeIssFjwB0b6a12opuRP7yo3E3gTCS KmbUuLv1CtxKQF+fUV1cVaTPMyT25Od+RC1K+iOR0F54oUJvJeq7fUzbn/KdlhA8XPGzwGRy 4zcsPWvwnXgfe5tk680fEKZVwOZKIEuJC3v+/yZpQzDvGYJvbyix0lHnrCzq43WefRHI5XTT QbM0WUIBIcGmq38+OgUsMYu4NzLu7uZFAcmp6h8g Organization: Linaro Developer Services In-Reply-To: <8d2ba0d3-55eb-45cf-b88a-bafef35e96b9@linux.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On 27/08/2023 12:31, Lucas Tanure wrote: > On 27-08-2023 11:23, Neil Armstrong wrote: >> Hi Lucas, >> >> Le 27/08/2023 à 12:04, Lucas Tanure a écrit : >>> On 27-08-2023 10:48, Neil Armstrong wrote: >>>> Hi Lucas, >>>> >>>> Le 27/08/2023 à 10:29, Lucas Tanure a écrit : >>>>> This reverts commit 6a4197f9763325043abf7690a21124a9facbf52e. >>>>> New SoC will use ttyS0 instead of ttyAML, so T7 SoC doesn't need a OF_EARLYCON_DECLARE. >>>>> >>>>> Signed-off-by: Lucas Tanure >>>>> --- >>>>> Since V1: >>>>> - add Signed-off-by: >>>>> >>>>>   drivers/tty/serial/meson_uart.c | 2 -- >>>>>   1 file changed, 2 deletions(-) >>>>> >>>>> diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c >>>>> index c4f61d82fb727..790d910dafa5d 100644 >>>>> --- a/drivers/tty/serial/meson_uart.c >>>>> +++ b/drivers/tty/serial/meson_uart.c >>>>> @@ -648,8 +648,6 @@ meson_serial_early_console_setup(struct earlycon_device *device, const char *opt >>>>>   OF_EARLYCON_DECLARE(meson, "amlogic,meson-ao-uart", >>>>>               meson_serial_early_console_setup); >>>>> -OF_EARLYCON_DECLARE(meson, "amlogic,t7-uart", >>>>> -            meson_serial_early_console_setup); >>>>>   #define MESON_SERIAL_CONSOLE_PTR(_devname) (&meson_serial_console_##_devname) >>>>>   #else >>>> >>>> How do you use earlycon with this removed ? >>>> >>>> Neil >>> This is my kernel cmdline: >>> console=ttyS0,921600 no_console_suspend earlycon=ttyS0,0xfe078000 >>> >>> And I can see my log: >>> boot 64bit kernel >>> [    0.000000] Booting Linux on physical CPU 0x0000000000 [0x410fd092] >>> [    0.000000] Linux version 6.5.0-rc7-next-20230825+ (tanureal@ryzen) (aarch64-none-linux-gnu-gcc (GNU Toolchain for the A-profile Architecture 10.3-2021.07 (arm-10.29)) 10.3.1 20210621, GNU ld (GNU Toolchain fo3 >>> [    0.000000] KASLR disabled due to lack of seed >>> [    0.000000] Machine model: Khadas vim4 >>> [    0.000000] OF: reserved mem: 0x0000000005000000..0x00000000052fffff (3072 KiB) nomap non-reusable secmon@5000000 >>> [    0.000000] OF: reserved mem: 0x0000000005300000..0x00000000072fffff (32768 KiB) nomap non-reusable secmon@5300000 >>> ... >>> [    0.079368] io scheduler mq-deadline registered >>> [    0.079374] io scheduler kyber registered >>> [    0.079549] io scheduler bfq registered >>> [    0.083373] fe078000.serial: ttyS0 at MMIO 0xfe078000 (irq = 14, base_baud = 1500000) is a meson_uart >>> [    0.083403] printk: console [ttyS0] enabled >>> >>> As the log is OK, and T7 for now is binding against S4 code we should drop this patch and add a S4 one if needed. >>> >>> But just having this log is not enough for testing earlycon? >>> I am assuming that by just having the log since 0.0000 is a good sign that earlycon is working. >>> Could you give further guidance? >> >> First the kernel argument is simply "earlycon" with no other options, >> the earlycon code will fetch the first uart using the DT /chosen/stdout-path property. >> >> Then you should see something like right after "Machine model": >> [    0.000000] earlycon: meson0 at MMIO 0x00000000ff803000 (options '115200n8') >> >> The boot log you share doesn't use earlycon, it waits until all depedency of the UART >> has been probed before probing the UART driver and prints the whole boot log. >> >> Earlycon is a mechanism to use the UART HW as configured by the bootloader in >> a minimal way very early in the boot in order to detect very early lockups. >> >> Keeping OF_EARLYCON_DECLARE for t7 would enable this. >> >> Neil >> >>> >>> Lucas Tanure >>> >> > But then we would need to add Earlycon for S4 too. > How can we add one Earlycon for all future SoCs, like S4 and T7? > As of today, S4 has an UART with amlogic,meson-ao-uart as fallback compatibl, but if there's no AO UART on S4, then this is wrong and yes a new OF_EARLYCON_DECLARE with amlogic,meson-s4-uart should be added. Neil