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Groups > linux.kernel > #1368312 > unrolled thread

[PATCH v7 0/5] ACPI: parse the SPCR table

Started byAleksey Makarov <aleksey.makarov@linaro.org>
First post2016-03-31 15:50 +0200
Last post2016-03-31 20:30 +0200
Articles 8 — 2 participants

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Contents

  [PATCH v7 0/5] ACPI: parse the SPCR table Aleksey Makarov <aleksey.makarov@linaro.org> - 2016-03-31 15:50 +0200
    [PATCH v7 5/5] serial: pl011: add console matching function Aleksey Makarov <aleksey.makarov@linaro.org> - 2016-03-31 15:50 +0200
    [PATCH v7 4/5] ARM64: ACPI: enable ACPI_SPCR_TABLE Aleksey Makarov <aleksey.makarov@linaro.org> - 2016-03-31 15:50 +0200
    [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial Aleksey Makarov <aleksey.makarov@linaro.org> - 2016-03-31 15:50 +0200
      Re: [PATCH v7 1/5] of/serial: move earlycon early_param handling to  serial Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-31 18:40 +0200
        Re: [PATCH v7 1/5] of/serial: move earlycon early_param handling to  serial Aleksey Makarov <aleksey.makarov@linaro.org> - 2016-03-31 19:10 +0200
          Re: [PATCH v7 1/5] of/serial: move earlycon early_param handling to  serial Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-31 19:40 +0200
            Re: [PATCH v7 1/5] of/serial: move earlycon early_param handling to  serial Aleksey Makarov <aleksey.makarov@linaro.org> - 2016-03-31 20:30 +0200

#1368312 — [PATCH v7 0/5] ACPI: parse the SPCR table

FromAleksey Makarov <aleksey.makarov@linaro.org>
Date2016-03-31 15:50 +0200
Subject[PATCH v7 0/5] ACPI: parse the SPCR table
Message-ID<riL8Z-5Qv-11@gated-at.bofh.it>
'ARM Server Base Boot Requirements' [1] mentions SPCR (Serial Port
Console Redirection Table) [2] as a mandatory ACPI table that
specifies the configuration of serial console.

Move "earlycon" early_param handling to earlycon.c to parse this option once

*** PATCH  "ACPICA: Headers: Add new constants for the DBG2 ACPI table"
*** IS JUST TO ENABLE BUILDING THE PATCHSET ON linux-next

Patch "ACPICA: Headers: Add new constants for the DBG2 ACPI table" is required
for the next patch.  It is taken from ACPICA series [3], but it has not appeared
in linux-next yet.

Parse SPCR table, setup earlycon and add register specified console.

Enable parsing this table on ARM64.  Earlycon should be set up
as early as possible.  ACPI boot tables are mapped in
arch/arm64/kernel/acpi.c:acpi_boot_table_init() called from setup_arch()
and that's where we parse spcr.  So it has to be opted-in per-arch.

Implement console_match() for pl011.

Based on the work by Leif Lindholm [4]
Thanks to Peter Hurley for explaining how this should work.

Should be applied to next-20160331.

Tested on QEMU.  SPCR support is included in QEMU's ARM mach-virt
since 2.4 release.

v7:
- add Acked-by: Rob Herring for "of/serial: move earlycon early_param handling
  to serial"
- call DT earlycon initialization from the arch ACPI code, not from parse_spcr()
  (Rafael J. Wysocki)
- fix a few minor issues (Rafael J. Wysocki)

v6:
https://lkml.kernel.org/g/1458823925-19560-1-git-send-email-aleksey.makarov@linaro.org
- add documentation for parse_spcr() functioin (Yury Norov)
- don't initialize err variable (Yury Norov)
- add __initdata for the earlycon_init_is_deferred flag variable
- rename the function exported in "of/serial: move earlycon early_param handling
  to serial" to avoid clash with the function from arch/microblaze/kernel/prom.c
- defer initialization of DT earlycon until DT/ACPI decision is made
  (Rob Herring, Peter Hurley)
- use snprintf instead of sprintf (Andy Shevchenko)
- drop patch that adds EARLYCON_DECLARE for pl011 as EARLYCON_DECLARE is
  equivalent to OF_EARLYCON_DECLARE for 4.6+ (Peter Hurley).  This means that
  SPCR earlycon will not work on the kernels before 4.6

v5:
https://lkml.kernel.org/g/1458643595-14719-1-git-send-email-aleksey.makarov@linaro.org
- drop patch "serial: pl011: use ACPI SPCR to setup 32-bit access" because
  it is ugly. Also because Christopher Covington came with a better solution [5]
- remove error message when the table is not provided by ACPI (Andy Shevchenko)
- rewrite spcr.c following the suggestions by Peter Hurley
- add console_match() for pl011 in a separate patch
- add EARLYCON_DECLARE for pl011 in a separate patch
- add patch "of/serial: move earlycon early_param handling to serial" from
  the GDB2 series

v4:
https://lkml.kernel.org/g/1456747355-15692-1-git-send-email-aleksey.makarov@linaro.org
- drop patch "ACPI: change __init to __ref for early_acpi_os_unmap_memory()"
  ACPI developers work on a new API and asked not to do that.
  Instead, use acpi_get_table_with_size()/early_acpi_os_unmap_memory() once
  and cache the result. (Lv Zheng)
- fix some style issues (Yury Norov)

v3:
https://lkml.kernel.org/g/1455559532-8305-1-git-send-email-aleksey.makarov@linaro.org

Greg Kroah-Hartman did not like v2 so I have rewritten this patchset:

- drop acpi_match() member of struct console
- drop implementations of this member for pl011 and 8250
- drop the patch that renames some vars in printk.c as it is not needed anymore
- drop patch that introduces system wide acpi_table_parse2().
  Instead introduce a custom acpi_table_parse_spcr() in spcr.c

Instead of introducing a new match_acpi() member of struct console,
this patchset introduces a new function acpi_console_check().
This function is called when a new uart is registered at serial_core.c
the same way OF code checks for console.  If the registered uart is the
console specified by SPCR table, this function calls add_preferred_console()

The restrictions of this approach are:

- only serial consoles can be set up
- only consoles specified by the memory/io address can be set up
  (SPCR can specify devices by PCI id/PCI address)

v2:
https://lkml.kernel.org/g/1455299022-11641-1-git-send-email-aleksey.makarov@linaro.org
- don't use SPCR if user specified console in command line
- fix initialization order of newcon->index = 0
- rename some variables at printk.c (Joe Perches, Peter Hurley)
- enable ACPI_SPCR_TABLE in a separate patch (Andy Shevchenko)
- remove the retry loop for console registering (Peter Hurley).
  Instead, obtain SPCR with acpi_get_table().  That works after
  call to acpi_early_init() i. e. in any *_initcall()
- describe design decision behind introducing acpi_match() (Peter Hurley)
- fix compilation for x86 + ACPI (Graeme Gregory)
- introduce DBG2 constants in a separate patch (Andy Shevchenko)
- fix a typo in DBG2 constants (Andy Shevchenko)
- add ACPI_DBG2_ARM_SBSA_32BIT constant (Christopher Covington)
- add support for ACPI_DBG2_ARM_SBSA_* consoles (Christopher Covington)
- add documentation for functions
- add a patch that uses SPCR to find if SBSA serial driver should use 32-bit
  accessor functions (Christopher Covington)
- change __init to __ref for early_acpi_os_unmap_memory() in a separate patch
- introduce acpi_table_parse2() in a separate patch
- fix fetching the SPCR table early (Mark Salter)
- add a patch from Mark Salter that introduces support for matching 8250-based
  consoles

v1:
https://lkml.kernel.org/g/1453722324-22407-1-git-send-email-aleksey.makarov@linaro.org

[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html
[2] https://msdn.microsoft.com/en-us/library/windows/hardware/dn639132(v=vs.85).aspx
[3] https://lkml.kernel.org/g/cover.1458714002.git.lv.zheng@intel.com
[4] https://lkml.kernel.org/g/1441716217-23786-1-git-send-email-leif.lindholm@linaro.org
[5] https://lkml.kernel.org/g/1457415800-8799-1-git-send-email-cov@codeaurora.org

Aleksey Makarov (4):
  ACPICA: Headers: Add new constants for the DBG2 ACPI table
  ACPI: parse SPCR and enable matching console
  ARM64: ACPI: enable ACPI_SPCR_TABLE
  serial: pl011: add console matching function

Leif Lindholm (1):
  of/serial: move earlycon early_param handling to serial

 arch/arm64/Kconfig              |   1 +
 arch/arm64/kernel/acpi.c        |  11 +++-
 drivers/acpi/Kconfig            |   3 ++
 drivers/acpi/Makefile           |   1 +
 drivers/acpi/spcr.c             | 111 ++++++++++++++++++++++++++++++++++++++++
 drivers/of/fdt.c                |  11 +---
 drivers/tty/serial/amba-pl011.c |  56 ++++++++++++++++++++
 drivers/tty/serial/earlycon.c   |  19 ++++++-
 include/acpi/actbl2.h           |   7 ++-
 include/linux/acpi.h            |   6 +++
 include/linux/of_fdt.h          |   2 +
 include/linux/serial_core.h     |   6 +++
 12 files changed, 220 insertions(+), 14 deletions(-)
 create mode 100644 drivers/acpi/spcr.c

-- 
2.7.4

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#1368313 — [PATCH v7 5/5] serial: pl011: add console matching function

FromAleksey Makarov <aleksey.makarov@linaro.org>
Date2016-03-31 15:50 +0200
Subject[PATCH v7 5/5] serial: pl011: add console matching function
Message-ID<riL8Z-5Qv-17@gated-at.bofh.it>
In reply to#1368312
This patch adds function pl011_console_match() that implements
method match of struct console.  It allows to match consoles against
data specified in a string, for example taken from command line or
compiled by ACPI SPCR table handler.

Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
---
 drivers/tty/serial/amba-pl011.c | 56 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 7c198e0..4139b64 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2287,12 +2287,68 @@ static int __init pl011_console_setup(struct console *co, char *options)
 	return uart_set_options(&uap->port, co, baud, parity, bits, flow);
 }
 
+/**
+ *	pl011_console_match - non-standard console matching
+ *	@co:	  registering console
+ *	@name:	  name from console command line
+ *	@idx:	  index from console command line
+ *	@options: ptr to option string from console command line
+ *
+ *	Only attempts to match console command lines of the form:
+ *	    console=pl011,mmio|mmio32,<addr>[,<options>]
+ *	    console=pl011,0x<addr>[,<options>]
+ *	This form is used to register an initial earlycon boot console and
+ *	replace it with the amba_console at pl011 driver init.
+ *
+ *	Performs console setup for a match (as required by interface)
+ *	If no <options> are specified, then assume the h/w is already setup.
+ *
+ *	Returns 0 if console matches; otherwise non-zero to use default matching
+ */
+static int __init pl011_console_match(struct console *co, char *name, int idx,
+				      char *options)
+{
+	char match[] = "pl011";	/* pl011-specific earlycon name */
+	unsigned char iotype;
+	unsigned long addr;
+	int i;
+
+	if (strncmp(name, match, 5) != 0)
+		return -ENODEV;
+
+	if (uart_parse_earlycon(options, &iotype, &addr, &options))
+		return -ENODEV;
+
+	/* try to match the port specified on the command line */
+	for (i = 0; i < ARRAY_SIZE(amba_ports); i++) {
+		struct uart_port *port;
+
+		if (!amba_ports[i])
+			continue;
+
+		port = &amba_ports[i]->port;
+
+		if (port->iotype != iotype)
+			continue;
+		if ((iotype == UPIO_MEM || iotype == UPIO_MEM32) &&
+		    (port->mapbase != addr))
+			continue;
+
+		co->index = i;
+		port->cons = co;
+		return pl011_console_setup(co, options);
+	}
+
+	return -ENODEV;
+}
+
 static struct uart_driver amba_reg;
 static struct console amba_console = {
 	.name		= "ttyAMA",
 	.write		= pl011_console_write,
 	.device		= uart_console_device,
 	.setup		= pl011_console_setup,
+	.match		= pl011_console_match,
 	.flags		= CON_PRINTBUFFER,
 	.index		= -1,
 	.data		= &amba_reg,
-- 
2.7.4

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#1368316 — [PATCH v7 4/5] ARM64: ACPI: enable ACPI_SPCR_TABLE

FromAleksey Makarov <aleksey.makarov@linaro.org>
Date2016-03-31 15:50 +0200
Subject[PATCH v7 4/5] ARM64: ACPI: enable ACPI_SPCR_TABLE
Message-ID<riL90-5Qv-19@gated-at.bofh.it>
In reply to#1368312
SBBR mentions SPCR as a mandatory ACPI table.  So enable it for ARM64

Earlycon should be set up as early as possible.  ACPI boot tables are
mapped in arch/arm64/kernel/acpi.c:acpi_boot_table_init() that
is called from setup_arch() and that's where we parse SPCR.
So it has to be opted-in per-arch.

When ACPI_SPCR_TABLE is defined initialization of DT earlycon is
deferred until the DT/ACPI decision is done.  Initialize DT earlycon
if ACPI is disabled.

Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
---
 arch/arm64/Kconfig       |  1 +
 arch/arm64/kernel/acpi.c | 11 ++++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 07b6a16..c77b4b2 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -3,6 +3,7 @@ config ARM64
 	select ACPI_CCA_REQUIRED if ACPI
 	select ACPI_GENERIC_GSI if ACPI
 	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
+	select ACPI_SPCR_TABLE if ACPI
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select ARCH_HAS_ELF_RANDOMIZE
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index d1ce8e2..f331ebb 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -24,6 +24,7 @@
 #include <linux/memblock.h>
 #include <linux/of_fdt.h>
 #include <linux/smp.h>
+#include <linux/serial_core.h>
 
 #include <asm/cputype.h>
 #include <asm/cpu_ops.h>
@@ -189,7 +190,7 @@ void __init acpi_boot_table_init(void)
 	 */
 	if (param_acpi_off ||
 	    (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
-		return;
+		goto done;
 
 	/*
 	 * ACPI is disabled at this point. Enable it in order to parse
@@ -209,6 +210,14 @@ void __init acpi_boot_table_init(void)
 		if (!param_acpi_force)
 			disable_acpi();
 	}
+
+done:
+	if (acpi_disabled) {
+		if (earlycon_init_is_deferred)
+			early_init_dt_scan_chosen_stdout();
+	} else {
+		parse_spcr(earlycon_init_is_deferred);
+	}
 }
 
 #ifdef CONFIG_ACPI_APEI
-- 
2.7.4

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#1368319 — [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial

FromAleksey Makarov <aleksey.makarov@linaro.org>
Date2016-03-31 15:50 +0200
Subject[PATCH v7 1/5] of/serial: move earlycon early_param handling to serial
Message-ID<riL90-5Qv-37@gated-at.bofh.it>
In reply to#1368312
From: Leif Lindholm <leif.lindholm@linaro.org>

We have multiple "earlycon" early_param handlers - merge the DT one into
the main earlycon one.  It's a cleanup that also will be useful
to defer setting up DT console until ACPI/DT decision is made.

Rename the exported function to avoid clashing with the function from
arch/microblaze/kernel/prom.c

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
---
 drivers/of/fdt.c              | 11 +----------
 drivers/tty/serial/earlycon.c |  2 +-
 include/linux/of_fdt.h        |  2 ++
 3 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 3349d2a..b50f775 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -805,7 +805,7 @@ static inline void early_init_dt_check_for_initrd(unsigned long node)
 
 #ifdef CONFIG_SERIAL_EARLYCON
 
-static int __init early_init_dt_scan_chosen_serial(void)
+int __init early_init_dt_scan_chosen_stdout(void)
 {
 	int offset;
 	const char *p, *q, *options = NULL;
@@ -849,15 +849,6 @@ static int __init early_init_dt_scan_chosen_serial(void)
 	}
 	return -ENODEV;
 }
-
-static int __init setup_of_earlycon(char *buf)
-{
-	if (buf)
-		return 0;
-
-	return early_init_dt_scan_chosen_serial();
-}
-early_param("earlycon", setup_of_earlycon);
 #endif
 
 /**
diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
index 067783f..7aae655 100644
--- a/drivers/tty/serial/earlycon.c
+++ b/drivers/tty/serial/earlycon.c
@@ -209,7 +209,7 @@ static int __init param_setup_earlycon(char *buf)
 	 * don't generate a warning from parse_early_params() in that case
 	 */
 	if (!buf || !buf[0])
-		return 0;
+		return early_init_dt_scan_chosen_stdout();
 
 	err = setup_earlycon(buf);
 	if (err == -ENOENT || err == -EALREADY)
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index 2fbe868..5cfe322 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -63,6 +63,7 @@ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname,
 				     int depth, void *data);
 extern int early_init_dt_scan_memory(unsigned long node, const char *uname,
 				     int depth, void *data);
+extern int early_init_dt_scan_chosen_stdout(void);
 extern void early_init_fdt_scan_reserved_mem(void);
 extern void early_init_fdt_reserve_self(void);
 extern void early_init_dt_add_memory_arch(u64 base, u64 size);
@@ -91,6 +92,7 @@ extern void early_get_first_memblock_info(void *, phys_addr_t *);
 extern u64 of_flat_dt_translate_address(unsigned long node);
 extern void of_fdt_limit_memory(int limit);
 #else /* CONFIG_OF_FLATTREE */
+static inline int early_init_dt_scan_chosen_stdout(void) { return -ENODEV; }
 static inline void early_init_fdt_scan_reserved_mem(void) {}
 static inline void early_init_fdt_reserve_self(void) {}
 static inline const char *of_flat_dt_get_machine_name(void) { return NULL; }
-- 
2.7.4

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#1368435 — Re: [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial

FromGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Date2016-03-31 18:40 +0200
SubjectRe: [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial
Message-ID<riNNw-7Pe-9@gated-at.bofh.it>
In reply to#1368319
On Thu, Mar 31, 2016 at 04:40:23PM +0300, Aleksey Makarov wrote:
> From: Leif Lindholm <leif.lindholm@linaro.org>
> 
> We have multiple "earlycon" early_param handlers - merge the DT one into
> the main earlycon one.  It's a cleanup that also will be useful
> to defer setting up DT console until ACPI/DT decision is made.
> 
> Rename the exported function to avoid clashing with the function from
> arch/microblaze/kernel/prom.c
> 
> Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
> Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
> Acked-by: Rob Herring <robh@kernel.org>
> ---
>  drivers/of/fdt.c              | 11 +----------
>  drivers/tty/serial/earlycon.c |  2 +-
>  include/linux/of_fdt.h        |  2 ++
>  3 files changed, 4 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 3349d2a..b50f775 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -805,7 +805,7 @@ static inline void early_init_dt_check_for_initrd(unsigned long node)
>  
>  #ifdef CONFIG_SERIAL_EARLYCON
>  
> -static int __init early_init_dt_scan_chosen_serial(void)
> +int __init early_init_dt_scan_chosen_stdout(void)
>  {
>  	int offset;
>  	const char *p, *q, *options = NULL;
> @@ -849,15 +849,6 @@ static int __init early_init_dt_scan_chosen_serial(void)
>  	}
>  	return -ENODEV;
>  }
> -
> -static int __init setup_of_earlycon(char *buf)
> -{
> -	if (buf)
> -		return 0;
> -
> -	return early_init_dt_scan_chosen_serial();
> -}
> -early_param("earlycon", setup_of_earlycon);
>  #endif
>  
>  /**
> diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
> index 067783f..7aae655 100644
> --- a/drivers/tty/serial/earlycon.c
> +++ b/drivers/tty/serial/earlycon.c
> @@ -209,7 +209,7 @@ static int __init param_setup_earlycon(char *buf)
>  	 * don't generate a warning from parse_early_params() in that case
>  	 */
>  	if (!buf || !buf[0])
> -		return 0;
> +		return early_init_dt_scan_chosen_stdout();
>  
>  	err = setup_earlycon(buf);
>  	if (err == -ENOENT || err == -EALREADY)
> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
> index 2fbe868..5cfe322 100644
> --- a/include/linux/of_fdt.h
> +++ b/include/linux/of_fdt.h
> @@ -63,6 +63,7 @@ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname,
>  				     int depth, void *data);
>  extern int early_init_dt_scan_memory(unsigned long node, const char *uname,
>  				     int depth, void *data);
> +extern int early_init_dt_scan_chosen_stdout(void);
>  extern void early_init_fdt_scan_reserved_mem(void);
>  extern void early_init_fdt_reserve_self(void);
>  extern void early_init_dt_add_memory_arch(u64 base, u64 size);
> @@ -91,6 +92,7 @@ extern void early_get_first_memblock_info(void *, phys_addr_t *);
>  extern u64 of_flat_dt_translate_address(unsigned long node);
>  extern void of_fdt_limit_memory(int limit);
>  #else /* CONFIG_OF_FLATTREE */
> +static inline int early_init_dt_scan_chosen_stdout(void) { return -ENODEV; }

Doesn't this change the default logic?  Today you are returning 0 if you
don't have this config option set, and now you return -ENODEV, did you
test this out?

thanks,

greg k-h

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#1368454 — Re: [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial

FromAleksey Makarov <aleksey.makarov@linaro.org>
Date2016-03-31 19:10 +0200
SubjectRe: [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial
Message-ID<riOgy-8hI-3@gated-at.bofh.it>
In reply to#1368435

On 03/31/2016 07:32 PM, Greg Kroah-Hartman wrote:
> On Thu, Mar 31, 2016 at 04:40:23PM +0300, Aleksey Makarov wrote:
>> From: Leif Lindholm <leif.lindholm@linaro.org>
>>
>> We have multiple "earlycon" early_param handlers - merge the DT one into
>> the main earlycon one.  It's a cleanup that also will be useful
>> to defer setting up DT console until ACPI/DT decision is made.
>>
>> Rename the exported function to avoid clashing with the function from
>> arch/microblaze/kernel/prom.c
>>
>> Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
>> Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
>> Acked-by: Rob Herring <robh@kernel.org>
>> ---
>>  drivers/of/fdt.c              | 11 +----------
>>  drivers/tty/serial/earlycon.c |  2 +-
>>  include/linux/of_fdt.h        |  2 ++
>>  3 files changed, 4 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
>> index 3349d2a..b50f775 100644
>> --- a/drivers/of/fdt.c
>> +++ b/drivers/of/fdt.c
>> @@ -805,7 +805,7 @@ static inline void early_init_dt_check_for_initrd(unsigned long node)
>>  
>>  #ifdef CONFIG_SERIAL_EARLYCON
>>  
>> -static int __init early_init_dt_scan_chosen_serial(void)
>> +int __init early_init_dt_scan_chosen_stdout(void)
>>  {
>>  	int offset;
>>  	const char *p, *q, *options = NULL;
>> @@ -849,15 +849,6 @@ static int __init early_init_dt_scan_chosen_serial(void)
>>  	}
>>  	return -ENODEV;
>>  }
>> -
>> -static int __init setup_of_earlycon(char *buf)
>> -{
>> -	if (buf)
>> -		return 0;
>> -
>> -	return early_init_dt_scan_chosen_serial();
>> -}
>> -early_param("earlycon", setup_of_earlycon);
>>  #endif
>>  
>>  /**
>> diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
>> index 067783f..7aae655 100644
>> --- a/drivers/tty/serial/earlycon.c
>> +++ b/drivers/tty/serial/earlycon.c
>> @@ -209,7 +209,7 @@ static int __init param_setup_earlycon(char *buf)
>>  	 * don't generate a warning from parse_early_params() in that case
>>  	 */
>>  	if (!buf || !buf[0])
>> -		return 0;
>> +		return early_init_dt_scan_chosen_stdout();
>>  
>>  	err = setup_earlycon(buf);
>>  	if (err == -ENOENT || err == -EALREADY)
>> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
>> index 2fbe868..5cfe322 100644
>> --- a/include/linux/of_fdt.h
>> +++ b/include/linux/of_fdt.h
>> @@ -63,6 +63,7 @@ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname,
>>  				     int depth, void *data);
>>  extern int early_init_dt_scan_memory(unsigned long node, const char *uname,
>>  				     int depth, void *data);
>> +extern int early_init_dt_scan_chosen_stdout(void);
>>  extern void early_init_fdt_scan_reserved_mem(void);
>>  extern void early_init_fdt_reserve_self(void);
>>  extern void early_init_dt_add_memory_arch(u64 base, u64 size);
>> @@ -91,6 +92,7 @@ extern void early_get_first_memblock_info(void *, phys_addr_t *);
>>  extern u64 of_flat_dt_translate_address(unsigned long node);
>>  extern void of_fdt_limit_memory(int limit);
>>  #else /* CONFIG_OF_FLATTREE */
>> +static inline int early_init_dt_scan_chosen_stdout(void) { return -ENODEV; }
> 
> Doesn't this change the default logic?  Today you are returning 0 if you
> don't have this config option set,

I am not sure I understand this.  Which return value do you mean?

1. early_init_dt_scan_chosen_stdout()

Today if CONFIG_OF_FLATTREE is not set then early_init_dt_scan_chosen_stdout() does not exist.

2. param_setup_earlycon()

Today we have 2 handlers for "earlycon" option.  One (in fdt.c) is for the option without args,
and another (earlycon.c) always expects agrs.  But both return 0 for the opposite cases becasue they
can not check what another hander returns.

Now we have just one handler and it can return correct value.

>  and now you return -ENODEV, did you
> test this out?

Yes, I tested it.

Thank you
Aleksey Makarov

> 
> thanks,
> 
> greg k-h
>

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#1368492 — Re: [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial

FromGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Date2016-03-31 19:40 +0200
SubjectRe: [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial
Message-ID<riOJB-8tH-39@gated-at.bofh.it>
In reply to#1368454
On Thu, Mar 31, 2016 at 08:04:20PM +0300, Aleksey Makarov wrote:
> 
> 
> On 03/31/2016 07:32 PM, Greg Kroah-Hartman wrote:
> > On Thu, Mar 31, 2016 at 04:40:23PM +0300, Aleksey Makarov wrote:
> >> From: Leif Lindholm <leif.lindholm@linaro.org>
> >>
> >> We have multiple "earlycon" early_param handlers - merge the DT one into
> >> the main earlycon one.  It's a cleanup that also will be useful
> >> to defer setting up DT console until ACPI/DT decision is made.
> >>
> >> Rename the exported function to avoid clashing with the function from
> >> arch/microblaze/kernel/prom.c
> >>
> >> Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
> >> Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
> >> Acked-by: Rob Herring <robh@kernel.org>
> >> ---
> >>  drivers/of/fdt.c              | 11 +----------
> >>  drivers/tty/serial/earlycon.c |  2 +-
> >>  include/linux/of_fdt.h        |  2 ++
> >>  3 files changed, 4 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> >> index 3349d2a..b50f775 100644
> >> --- a/drivers/of/fdt.c
> >> +++ b/drivers/of/fdt.c
> >> @@ -805,7 +805,7 @@ static inline void early_init_dt_check_for_initrd(unsigned long node)
> >>  
> >>  #ifdef CONFIG_SERIAL_EARLYCON
> >>  
> >> -static int __init early_init_dt_scan_chosen_serial(void)
> >> +int __init early_init_dt_scan_chosen_stdout(void)
> >>  {
> >>  	int offset;
> >>  	const char *p, *q, *options = NULL;
> >> @@ -849,15 +849,6 @@ static int __init early_init_dt_scan_chosen_serial(void)
> >>  	}
> >>  	return -ENODEV;
> >>  }
> >> -
> >> -static int __init setup_of_earlycon(char *buf)
> >> -{
> >> -	if (buf)
> >> -		return 0;
> >> -
> >> -	return early_init_dt_scan_chosen_serial();
> >> -}
> >> -early_param("earlycon", setup_of_earlycon);
> >>  #endif
> >>  
> >>  /**
> >> diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
> >> index 067783f..7aae655 100644
> >> --- a/drivers/tty/serial/earlycon.c
> >> +++ b/drivers/tty/serial/earlycon.c
> >> @@ -209,7 +209,7 @@ static int __init param_setup_earlycon(char *buf)
> >>  	 * don't generate a warning from parse_early_params() in that case
> >>  	 */
> >>  	if (!buf || !buf[0])
> >> -		return 0;
> >> +		return early_init_dt_scan_chosen_stdout();
> >>  
> >>  	err = setup_earlycon(buf);
> >>  	if (err == -ENOENT || err == -EALREADY)
> >> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
> >> index 2fbe868..5cfe322 100644
> >> --- a/include/linux/of_fdt.h
> >> +++ b/include/linux/of_fdt.h
> >> @@ -63,6 +63,7 @@ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname,
> >>  				     int depth, void *data);
> >>  extern int early_init_dt_scan_memory(unsigned long node, const char *uname,
> >>  				     int depth, void *data);
> >> +extern int early_init_dt_scan_chosen_stdout(void);
> >>  extern void early_init_fdt_scan_reserved_mem(void);
> >>  extern void early_init_fdt_reserve_self(void);
> >>  extern void early_init_dt_add_memory_arch(u64 base, u64 size);
> >> @@ -91,6 +92,7 @@ extern void early_get_first_memblock_info(void *, phys_addr_t *);
> >>  extern u64 of_flat_dt_translate_address(unsigned long node);
> >>  extern void of_fdt_limit_memory(int limit);
> >>  #else /* CONFIG_OF_FLATTREE */
> >> +static inline int early_init_dt_scan_chosen_stdout(void) { return -ENODEV; }
> > 
> > Doesn't this change the default logic?  Today you are returning 0 if you
> > don't have this config option set,
> 
> I am not sure I understand this.  Which return value do you mean?
> 
> 1. early_init_dt_scan_chosen_stdout()
> 
> Today if CONFIG_OF_FLATTREE is not set then early_init_dt_scan_chosen_stdout() does not exist.

It "exists" in that you return -ENODEV, right?  Look at the place where
you called this function, previously you returned 0, now you return this
function call's return value.

> 2. param_setup_earlycon()
> 
> Today we have 2 handlers for "earlycon" option.  One (in fdt.c) is for the option without args,
> and another (earlycon.c) always expects agrs.  But both return 0 for the opposite cases becasue they
> can not check what another hander returns.
> 
> Now we have just one handler and it can return correct value.

I don't understand.

> >  and now you return -ENODEV, did you
> > test this out?
> 
> Yes, I tested it.

On what platforms?  With what configurations?

thanks,

greg k-h

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#1368528 — Re: [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial

FromAleksey Makarov <aleksey.makarov@linaro.org>
Date2016-03-31 20:30 +0200
SubjectRe: [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial
Message-ID<riPvY-BA-21@gated-at.bofh.it>
In reply to#1368492

On 03/31/2016 08:37 PM, Greg Kroah-Hartman wrote:
> On Thu, Mar 31, 2016 at 08:04:20PM +0300, Aleksey Makarov wrote:
>>
>>
>> On 03/31/2016 07:32 PM, Greg Kroah-Hartman wrote:
>>> On Thu, Mar 31, 2016 at 04:40:23PM +0300, Aleksey Makarov wrote:
>>>> From: Leif Lindholm <leif.lindholm@linaro.org>
>>>>
>>>> We have multiple "earlycon" early_param handlers - merge the DT one into
>>>> the main earlycon one.  It's a cleanup that also will be useful
>>>> to defer setting up DT console until ACPI/DT decision is made.
>>>>
>>>> Rename the exported function to avoid clashing with the function from
>>>> arch/microblaze/kernel/prom.c
>>>>
>>>> Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
>>>> Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
>>>> Acked-by: Rob Herring <robh@kernel.org>
>>>> ---
>>>>  drivers/of/fdt.c              | 11 +----------
>>>>  drivers/tty/serial/earlycon.c |  2 +-
>>>>  include/linux/of_fdt.h        |  2 ++
>>>>  3 files changed, 4 insertions(+), 11 deletions(-)
>>>>
>>>> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
>>>> index 3349d2a..b50f775 100644
>>>> --- a/drivers/of/fdt.c
>>>> +++ b/drivers/of/fdt.c
>>>> @@ -805,7 +805,7 @@ static inline void early_init_dt_check_for_initrd(unsigned long node)
>>>>  
>>>>  #ifdef CONFIG_SERIAL_EARLYCON
>>>>  
>>>> -static int __init early_init_dt_scan_chosen_serial(void)
>>>> +int __init early_init_dt_scan_chosen_stdout(void)
>>>>  {
>>>>  	int offset;
>>>>  	const char *p, *q, *options = NULL;
>>>> @@ -849,15 +849,6 @@ static int __init early_init_dt_scan_chosen_serial(void)
>>>>  	}
>>>>  	return -ENODEV;
>>>>  }
>>>> -
>>>> -static int __init setup_of_earlycon(char *buf)
>>>> -{
>>>> -	if (buf)
>>>> -		return 0;
>>>> -
>>>> -	return early_init_dt_scan_chosen_serial();
>>>> -}
>>>> -early_param("earlycon", setup_of_earlycon);
>>>>  #endif
>>>>  
>>>>  /**
>>>> diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
>>>> index 067783f..7aae655 100644
>>>> --- a/drivers/tty/serial/earlycon.c
>>>> +++ b/drivers/tty/serial/earlycon.c
>>>> @@ -209,7 +209,7 @@ static int __init param_setup_earlycon(char *buf)
>>>>  	 * don't generate a warning from parse_early_params() in that case
>>>>  	 */
>>>>  	if (!buf || !buf[0])
>>>> -		return 0;
>>>> +		return early_init_dt_scan_chosen_stdout();
>>>>  
>>>>  	err = setup_earlycon(buf);
>>>>  	if (err == -ENOENT || err == -EALREADY)
>>>> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
>>>> index 2fbe868..5cfe322 100644
>>>> --- a/include/linux/of_fdt.h
>>>> +++ b/include/linux/of_fdt.h
>>>> @@ -63,6 +63,7 @@ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname,
>>>>  				     int depth, void *data);
>>>>  extern int early_init_dt_scan_memory(unsigned long node, const char *uname,
>>>>  				     int depth, void *data);
>>>> +extern int early_init_dt_scan_chosen_stdout(void);
>>>>  extern void early_init_fdt_scan_reserved_mem(void);
>>>>  extern void early_init_fdt_reserve_self(void);
>>>>  extern void early_init_dt_add_memory_arch(u64 base, u64 size);
>>>> @@ -91,6 +92,7 @@ extern void early_get_first_memblock_info(void *, phys_addr_t *);
>>>>  extern u64 of_flat_dt_translate_address(unsigned long node);
>>>>  extern void of_fdt_limit_memory(int limit);
>>>>  #else /* CONFIG_OF_FLATTREE */
>>>> +static inline int early_init_dt_scan_chosen_stdout(void) { return -ENODEV; }
>>>
>>> Doesn't this change the default logic?  Today you are returning 0 if you
>>> don't have this config option set,
>>
>> I am not sure I understand this.  Which return value do you mean?
>>
>> 1. early_init_dt_scan_chosen_stdout()
>>
>> Today if CONFIG_OF_FLATTREE is not set then early_init_dt_scan_chosen_stdout() does not exist.
> 
> It "exists" in that you return -ENODEV, right?  Look at the place where
> you called this function,

It's param_setup_earlycon() so see below for explanations.

> previously you returned 0, now you return this
> function call's return value.
> 
>> 2. param_setup_earlycon()
>>
>> Today we have 2 handlers for "earlycon" option.  One (in fdt.c) is for the option without args,
>> and another (earlycon.c) always expects agrs.  But both return 0 for the opposite cases becasue they
>> can not check what another hander returns.
>>
>> Now we have just one handler and it can return correct value.
> 
> I don't understand.

This patch deletes early_param("earlycon", setup_of_earlycon) from fdt.c and
keeps early_param("earlycon", param_setup_earlycon) in earlycon.c.

Assume "earlycon" kernel command line parameter was passed without arguments.

Before this patch:

early_init_dt_scan_chosen_stdout() is called from setup_of_earlycon()
where its return value is returned to parse_early_param()

After this patch:

early_init_dt_scan_chosen_stdout() is called from param_setup_earlycon()
so we should return its return value from param_setup_earlycon() if we want
to pass it to parse_early_param().

>>>  and now you return -ENODEV, did you
>>> test this out?
>>
>> Yes, I tested it.
> 
> On what platforms?  With what configurations?

platform: QEMU
configuration options: with/without acpi, dt
command line options: with/without "earlycon", "earlycon=..."

Thank you
Aleksey Makarov

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