From: Stefano Stabellini <sstabellini@kernel.org>
To: Anthony PERARD <anthony.perard@citrix.com>
Cc: "Stefano Stabellini" <sstabellini@kernel.org>,
"Julien Grall" <julien@xen.org>, "Wei Liu" <wl@xen.org>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Ian Jackson" <ian.jackson@eu.citrix.com>,
"George Dunlap" <george.dunlap@citrix.com>,
"Julien Grall" <julien.grall@arm.com>,
"Jan Beulich" <jbeulich@suse.com>,
xen-devel@lists.xenproject.org,
"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [XEN PATCH v3 2/2] xen/arm: Configure early printk via Kconfig
Date: Fri, 13 Mar 2020 16:12:17 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.21.2003131605490.1269@sstabellini-ThinkPad-T480s> (raw)
In-Reply-To: <20200309174505.594607-3-anthony.perard@citrix.com>
On Mon, 9 Mar 2020, Anthony PERARD wrote:
> At the moment, early printk can only be configured on the make command
> line. It is not very handy because a user has to remove the option
> everytime it is using another command other than compiling the
> hypervisor.
>
> Furthermore, early printk is one of the few odds one that are not
> using Kconfig.
>
> So this is about time to move it to Kconfig.
>
> The new kconfigs options allow a user to eather select a UART driver
> to use at boot time, and set the parameters, or it is still possible
> to select a platform which will set the parameters.
>
> If CONFIG_EARLY_PRINTK is present in the environment or on the make
> command line, make will return an error.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
>
> ---
>
> Original patch:
> [PATCH for-4.13] xen/arm: Add Skeleton for using configuring early printk using Kconfig
> <20190913103953.8182-1-julien.grall@arm.com>
> ---
>
> Notes:
> v3:
> - rename EARLY_PRINK to CONFIG_EARLY_PRINTK in makefile here (which
> select which object to build).
> - rename EARLY_UART_BAUD_RATE to EARLY_UART_PL011_BAUD_RATE
> - typos
> - drop the list of aliases in early-printk.txt. Kconfig choice menu
> should be enough.
> - reword early-printk.txt.
> - rework how EARLY_PRINTK is set to Y
> and use that instead of a list of all EARLY_UART_*
> - Add a check to ask user to use Kconfig to set early printk.
> - rework the possible choice to have all uart driver and platform
> specific option together.
> - have added or reword prompt and help messages of the different
> options. The platform specific option don't have extended help, the
> prompt is probably enough.
> (The non-platform specific options have the help message that Julien
> have written in the first version.)
> - have made EARLY_UART_INIT dependent on the value of
> EARLY_UART_PL011_BAUD_RATE so that there is no need to expose _INIT to
> users.
>
The patch is fine by me. I only have one very minor comment below.
> + config EARLY_UART_CHOICE_CADENCE
> + select EARLY_UART_CADENCE
> + depends on ARM_64
> + bool "Early printk via Cadence UART"
> + help
> + Say Y here if you wish the early printk to direct their
> + output to a Cadence UART. You can use this option to
> + provide the parameters for the Cadence UART rather than
> + selecting one of the platform specific options below if
> + you know the parameters for the port.
> +
> + This option is preferred over the platform specific
> + options; the platform specific options are deprecated
> + and will soon be removed.
[...]
> + config EARLY_PRINTK_ZYNQMP
> + bool "Early printk with Cadence UART for Xilinx ZynqMP SoCs"
> + select EARLY_UART_CADENCE
> + depends on ARM_64
> +endchoice
[...]
> +config EARLY_UART_BASE_ADDRESS
> + depends on EARLY_PRINTK
> + hex "Early printk, physical base address of debug UART"
> + default 0xF040AB00 if EARLY_PRINTK_BRCM
> + default 0x4806A000 if EARLY_PRINTK_DRA7
> + default 0x1c090000 if EARLY_PRINTK_FASTMODEL
> + default 0x12c20000 if EARLY_PRINTK_EXYNOS5250
> + default 0xfff32000 if EARLY_PRINTK_HIKEY960
> + default 0x7ff80000 if EARLY_PRINTK_JUNO
> + default 0xe6e60000 if EARLY_PRINTK_LAGER
> + default 0xfff36000 if EARLY_PRINTK_MIDWAY
> + default 0xd0012000 if EARLY_PRINTK_MVEBU
> + default 0x48020000 if EARLY_PRINTK_OMAP5432
> + default 0xe6e88000 if EARLY_PRINTK_RCAR3
> + default 0xe1010000 if EARLY_PRINTK_SEATTLE
> + default 0x01c28000 if EARLY_PRINTK_SUN6I
> + default 0x01c28000 if EARLY_PRINTK_SUN7I
> + default 0x87e024000000 if EARLY_PRINTK_THUNDERX
> + default 0x1c090000 if EARLY_PRINTK_VEXPRESS
> + default 0x1c021000 if EARLY_PRINTK_XGENE_MCDIVITT
> + default 0x1c020000 if EARLY_PRINTK_XGENE_STORM
> + default 0xff000000 if EARLY_PRINTK_ZYNQMP
Today we only have one board with CADENCE UART which is ZynqMP. However,
only if EARLY_PRINTK_ZYNQMP is selected the BASE_ADDRESS is default to
0xff000000.
Ideally, BASE_ADDRESS would default to 0xff000000 if EARLY_PRINTK_ZYNQMP
or if EARLY_UART_CADENCE. (There is one more similar example which is
EARLY_UART_EXYNOS4210.)
I don't know if it is worth optimizing, I'll let you and Julien decide.
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next prev parent reply other threads:[~2020-03-13 23:12 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 17:45 [Xen-devel] [XEN PATCH v3 0/2] xen/arm: Configure early printk via Kconfig Anthony PERARD
2020-03-09 17:45 ` [Xen-devel] [XEN PATCH v3 1/2] xen/arm: Rename all early printk macro Anthony PERARD
2020-03-11 13:57 ` Julien Grall
2020-03-11 14:46 ` Anthony PERARD
2020-03-12 20:18 ` Julien Grall
2020-03-13 23:01 ` Stefano Stabellini
2020-03-09 17:45 ` [Xen-devel] [XEN PATCH v3 2/2] xen/arm: Configure early printk via Kconfig Anthony PERARD
2020-03-11 14:18 ` Julien Grall
[not found] ` <20200311152613.GJ2152@perard.uk.xensource.com>
2020-03-11 17:21 ` Julien Grall
2020-03-11 17:38 ` Anthony PERARD
2020-03-12 20:16 ` Julien Grall
2020-03-13 23:12 ` Stefano Stabellini [this message]
2020-03-13 23:14 ` Stefano Stabellini
2020-03-17 9:36 ` Julien Grall
2020-03-17 17:51 ` Stefano Stabellini
2020-03-24 14:48 ` Anthony PERARD
2020-03-13 23:19 ` Julien Grall
2020-03-13 23:37 ` Julien Grall
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