'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 "ACPI: add definitions of DBG2 subtypes" is required for the next patch.
ACPI maintainers said that they had got it for the next release of ACPICA,
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 [3]
Thanks to Peter Hurley for explaining how this should work.
Should be applied to next-20160324.
Tested on QEMU. SPCR support is included in QEMU's ARM mach-virt
since 2.4 release.
v6:
- 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/[email protected]
- 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 [4]
- 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/[email protected]
- 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/[email protected]
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/[email protected]
- 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/[email protected]
[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/[email protected]
[4] https://lkml.kernel.org/g/[email protected]
Aleksey Makarov (4):
ACPI: add definitions of DBG2 subtypes
ACPI: parse SPCR and enable matching console
ACPI: enable ACPI_SPCR_TABLE on ARM64
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 | 5 +-
drivers/acpi/Kconfig | 3 +
drivers/acpi/Makefile | 1 +
drivers/acpi/spcr.c | 125 ++++++++++++++++++++++++++++++++++++++++
drivers/of/fdt.c | 11 +---
drivers/tty/serial/amba-pl011.c | 56 ++++++++++++++++++
drivers/tty/serial/earlycon.c | 11 +++-
include/acpi/actbl2.h | 5 ++
include/linux/acpi.h | 8 +++
include/linux/of_fdt.h | 2 +
11 files changed, 215 insertions(+), 13 deletions(-)
create mode 100644 drivers/acpi/spcr.c
--
2.7.4
The recent version of Microsoft Debug Port Table 2 (DBG2) [1]
specifies additional serial debug port subtypes. These constants
are also referred by Serial Port Console Redirection Table (SPCR) [2]
Add these constants.
[1] https://msdn.microsoft.com/en-us/library/windows/hardware/dn639131(v=vs.85).aspx
[2] https://msdn.microsoft.com/en-us/library/windows/hardware/dn639132(v=vs.85).aspx
Signed-off-by: Aleksey Makarov <[email protected]>
---
include/acpi/actbl2.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h
index a4ef625..652f747 100644
--- a/include/acpi/actbl2.h
+++ b/include/acpi/actbl2.h
@@ -371,6 +371,11 @@ struct acpi_dbg2_device {
#define ACPI_DBG2_16550_COMPATIBLE 0x0000
#define ACPI_DBG2_16550_SUBSET 0x0001
+#define ACPI_DBG2_ARM_PL011 0x0003
+#define ACPI_DBG2_ARM_SBSA_32BIT 0x000D
+#define ACPI_DBG2_ARM_SBSA_GENERIC 0x000E
+#define ACPI_DBG2_ARM_DCC 0x000F
+#define ACPI_DBG2_BCM2835 0x0010
#define ACPI_DBG2_1394_STANDARD 0x0000
--
2.7.4
'ARM Server Base Boot Requiremets' [1] mentions SPCR (Serial Port
Console Redirection Table) [2] as a mandatory ACPI table that
specifies the configuration of serial console.
Defer initialization of DT earlycon until ACPI/DT decision is made.
If ACPI is enabled, parse the table, setup earlycon
and enable the specified console.
If it is disabled, try to set up earlycon from DT.
Thanks to Peter Hurley for explaining how this should work.
[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
Signed-off-by: Aleksey Makarov <[email protected]>
---
drivers/acpi/Kconfig | 3 +
drivers/acpi/Makefile | 1 +
drivers/acpi/spcr.c | 125 ++++++++++++++++++++++++++++++++++++++++++
drivers/tty/serial/earlycon.c | 11 +++-
include/linux/acpi.h | 8 +++
5 files changed, 146 insertions(+), 2 deletions(-)
create mode 100644 drivers/acpi/spcr.c
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 65fb483..5611eb6 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -77,6 +77,9 @@ config ACPI_DEBUGGER_USER
endif
+config ACPI_SPCR_TABLE
+ bool
+
config ACPI_SLEEP
bool
depends on SUSPEND || HIBERNATION
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 7395928..f70ae14 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -82,6 +82,7 @@ obj-$(CONFIG_ACPI_EC_DEBUGFS) += ec_sys.o
obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
obj-$(CONFIG_ACPI_BGRT) += bgrt.o
obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o
+obj-$(CONFIG_ACPI_SPCR_TABLE) += spcr.o
obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o
# processor has its own "processor." module_param namespace
diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
new file mode 100644
index 0000000..31e667e
--- /dev/null
+++ b/drivers/acpi/spcr.c
@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2012, Intel Corporation
+ * Copyright (c) 2015, Red Hat, Inc.
+ * Copyright (c) 2015, 2016 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#define pr_fmt(fmt) "ACPI: SPCR: " fmt
+
+#include <linux/acpi.h>
+#include <linux/console.h>
+#include <linux/kernel.h>
+#include <linux/serial_core.h>
+#include <linux/of_fdt.h>
+
+static bool earlycon_init_is_deferred __initdata;
+
+void __init defer_earlycon_init(void)
+{
+ earlycon_init_is_deferred = true;
+}
+
+/**
+ * parse_spcr() - parse ACPI SPCR table and add preferred console
+ *
+ * For the architectures with support for ACPI, CONFIG_ACPI_SPCR_TABLE may be
+ * defined to parse ACPI SPCR table. As a result of the parsing preferred
+ * console is registered.
+ *
+ * When CONFIG_ACPI_SPCR_TABLE is defined, this function should should be called
+ * from arch inintialization code as soon as the DT/ACPI decision is made.
+ *
+ * When CONFIG_ACPI_SPCR_TABLE is defined, "earlycon" without parameters in
+ * command line does not start DT earlycon immediately, instead it defers
+ * starting it until DT/ACPI decision is made. If ACPI is enabled at that time,
+ * parse_spcr() parses the table, adds preferred console and sets up it as an
+ * earlycon. If ACPI is disabled at that time, it tries to set up earlycon
+ * from DT.
+ */
+int __init parse_spcr(void)
+{
+#define OPTS_LEN 64
+ static char opts[OPTS_LEN];
+ struct acpi_table_spcr *table;
+ acpi_size table_size;
+ acpi_status status;
+ char *uart;
+ char *iotype;
+ int baud_rate;
+ int err;
+
+ if (acpi_disabled)
+ return earlycon_init_is_deferred ?
+ early_init_dt_scan_chosen_stdout() : 0;
+
+ status = acpi_get_table_with_size(ACPI_SIG_SPCR, 0,
+ (struct acpi_table_header **)&table,
+ &table_size);
+
+ if (ACPI_FAILURE(status))
+ return -ENOENT;
+
+ if (table->header.revision < 2) {
+ err = -EINVAL;
+ pr_err("wrong table version\n");
+ goto done;
+ }
+
+ iotype = (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) ?
+ "mmio" : "io";
+
+ switch (table->interface_type) {
+ case ACPI_DBG2_ARM_SBSA_32BIT:
+ iotype = "mmio32";
+ /* fall through */
+ case ACPI_DBG2_ARM_PL011:
+ case ACPI_DBG2_ARM_SBSA_GENERIC:
+ case ACPI_DBG2_BCM2835:
+ uart = "pl011";
+ break;
+ case ACPI_DBG2_16550_COMPATIBLE:
+ case ACPI_DBG2_16550_SUBSET:
+ uart = "uart";
+ break;
+ default:
+ err = -ENOENT;
+ goto done;
+ }
+
+ switch (table->baud_rate) {
+ case 3:
+ baud_rate = 9600;
+ break;
+ case 4:
+ baud_rate = 19200;
+ break;
+ case 6:
+ baud_rate = 57600;
+ break;
+ case 7:
+ baud_rate = 115200;
+ break;
+ default:
+ err = -ENOENT;
+ goto done;
+ }
+
+ snprintf(opts, OPTS_LEN, "%s,%s,0x%llx,%d", uart, iotype,
+ table->serial_port.address, baud_rate);
+
+ pr_info("console: %s", opts);
+
+ if (earlycon_init_is_deferred)
+ setup_earlycon(opts);
+
+ err = add_preferred_console(uart, 0, opts + strlen(uart) + 1);
+
+done:
+ early_acpi_os_unmap_memory((void __iomem *)table, table_size);
+ return err;
+}
diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
index 7aae655..ed6aaf8 100644
--- a/drivers/tty/serial/earlycon.c
+++ b/drivers/tty/serial/earlycon.c
@@ -21,6 +21,7 @@
#include <linux/sizes.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
+#include <linux/acpi.h>
#ifdef CONFIG_FIX_EARLYCON_MEM
#include <asm/fixmap.h>
@@ -208,8 +209,14 @@ static int __init param_setup_earlycon(char *buf)
* Just 'earlycon' is a valid param for devicetree earlycons;
* don't generate a warning from parse_early_params() in that case
*/
- if (!buf || !buf[0])
- return early_init_dt_scan_chosen_stdout();
+ if (!buf || !buf[0]) {
+ if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE)) {
+ defer_earlycon_init();
+ return 0;
+ } else {
+ return early_init_dt_scan_chosen_stdout();
+ }
+ }
err = setup_earlycon(buf);
if (err == -ENOENT || err == -EALREADY)
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 06ed7e5..3523995 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1004,4 +1004,12 @@ static inline struct fwnode_handle *acpi_get_next_subnode(struct device *dev,
#define acpi_probe_device_table(t) ({ int __r = 0; __r;})
#endif
+#ifdef CONFIG_ACPI_SPCR_TABLE
+int parse_spcr(void);
+void defer_earlycon_init(void);
+#else
+static inline int parse_spcr(void) { return 0; }
+static inline void defer_earlycon_init(void) { }
+#endif
+
#endif /*_LINUX_ACPI_H*/
--
2.7.4
From: Leif Lindholm <[email protected]>
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 <[email protected]>
Signed-off-by: Aleksey Makarov <[email protected]>
---
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
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 <[email protected]>
---
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
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() called from
setup_arch() and that's where we parse SPCR. So it has to be opted-in
per-arch.
Signed-off-by: Aleksey Makarov <[email protected]>
---
arch/arm64/Kconfig | 1 +
arch/arm64/kernel/acpi.c | 5 ++++-
2 files changed, 5 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..046f095 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -189,7 +189,7 @@ 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 +209,9 @@ void __init acpi_boot_table_init(void)
if (!param_acpi_force)
disable_acpi();
}
+
+done:
+ parse_spcr();
}
#ifdef CONFIG_ACPI_APEI
--
2.7.4
On Thu, Mar 24, 2016 at 1:51 PM, Aleksey Makarov
<[email protected]> wrote:
> '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 "ACPI: add definitions of DBG2 subtypes" is required for the next patch.
> ACPI maintainers said that they had got it for the next release of ACPICA,
> but it has not appeared in linux-next yet.
It will. Patches containing it have just been posted.
> 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 [3]
> Thanks to Peter Hurley for explaining how this should work.
>
> Should be applied to next-20160324.
>
> Tested on QEMU. SPCR support is included in QEMU's ARM mach-virt
> since 2.4 release.
Honestly, I'm not sure why I'm regarded as the right maintainer to send this to.
The only patch here touching generic ACPI code is [3/5] (the [2/5] is
going in through ACPICA) and the rest is all about ARM64 AFAICS. Why
don't you send it to the ARM64 maintainers instead?
I'll have some comments on [3/5], I'll send them later today or tomorrow.
Thanks,
Rafael
We implemented all of these in ACPICA version 20160318.
> -----Original Message-----
> From: Aleksey Makarov [mailto:[email protected]]
> Sent: Thursday, March 24, 2016 5:52 AM
> To: Greg Kroah-Hartman; Rafael J . Wysocki; Len Brown
> Cc: [email protected]; [email protected]; linux-
> [email protected]; [email protected]; Aleksey
> Makarov; Russell King; Leif Lindholm; Graeme Gregory; Al Stone;
> Christopher Covington; Yury Norov; Peter Hurley; Zheng, Lv; Moore, Robert;
> Wysocki, Rafael J; [email protected]
> Subject: [PATCH v6 2/5] ACPI: add definitions of DBG2 subtypes
>
> The recent version of Microsoft Debug Port Table 2 (DBG2) [1] specifies
> additional serial debug port subtypes. These constants are also referred
> by Serial Port Console Redirection Table (SPCR) [2]
>
> Add these constants.
>
> [1] https://msdn.microsoft.com/en-
> us/library/windows/hardware/dn639131(v=vs.85).aspx
> [2] https://msdn.microsoft.com/en-
> us/library/windows/hardware/dn639132(v=vs.85).aspx
>
> Signed-off-by: Aleksey Makarov <[email protected]>
> ---
> include/acpi/actbl2.h | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h index
> a4ef625..652f747 100644
> --- a/include/acpi/actbl2.h
> +++ b/include/acpi/actbl2.h
> @@ -371,6 +371,11 @@ struct acpi_dbg2_device {
>
> #define ACPI_DBG2_16550_COMPATIBLE 0x0000
> #define ACPI_DBG2_16550_SUBSET 0x0001
> +#define ACPI_DBG2_ARM_PL011 0x0003
> +#define ACPI_DBG2_ARM_SBSA_32BIT 0x000D
> +#define ACPI_DBG2_ARM_SBSA_GENERIC 0x000E
> +#define ACPI_DBG2_ARM_DCC 0x000F
> +#define ACPI_DBG2_BCM2835 0x0010
>
> #define ACPI_DBG2_1394_STANDARD 0x0000
>
> --
> 2.7.4
On Thu, Mar 24, 2016 at 7:51 AM, Aleksey Makarov
<[email protected]> wrote:
> From: Leif Lindholm <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Aleksey Makarov <[email protected]>
Acked-by: Rob Herring <[email protected]>
On Thursday, March 24, 2016 03:52:01 PM Aleksey Makarov wrote:
> 'ARM Server Base Boot Requiremets' [1] mentions SPCR (Serial Port
> Console Redirection Table) [2] as a mandatory ACPI table that
> specifies the configuration of serial console.
>
> Defer initialization of DT earlycon until ACPI/DT decision is made.
>
> If ACPI is enabled, parse the table, setup earlycon
> and enable the specified console.
>
> If it is disabled, try to set up earlycon from DT.
>
> Thanks to Peter Hurley for explaining how this should work.
>
> [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
>
> Signed-off-by: Aleksey Makarov <[email protected]>
> ---
> drivers/acpi/Kconfig | 3 +
> drivers/acpi/Makefile | 1 +
> drivers/acpi/spcr.c | 125 ++++++++++++++++++++++++++++++++++++++++++
> drivers/tty/serial/earlycon.c | 11 +++-
> include/linux/acpi.h | 8 +++
> 5 files changed, 146 insertions(+), 2 deletions(-)
> create mode 100644 drivers/acpi/spcr.c
>
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 65fb483..5611eb6 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -77,6 +77,9 @@ config ACPI_DEBUGGER_USER
>
> endif
>
> +config ACPI_SPCR_TABLE
> + bool
> +
> config ACPI_SLEEP
> bool
> depends on SUSPEND || HIBERNATION
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 7395928..f70ae14 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -82,6 +82,7 @@ obj-$(CONFIG_ACPI_EC_DEBUGFS) += ec_sys.o
> obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
> obj-$(CONFIG_ACPI_BGRT) += bgrt.o
> obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o
> +obj-$(CONFIG_ACPI_SPCR_TABLE) += spcr.o
> obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o
>
> # processor has its own "processor." module_param namespace
> diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
> new file mode 100644
> index 0000000..31e667e
> --- /dev/null
> +++ b/drivers/acpi/spcr.c
> @@ -0,0 +1,125 @@
> +/*
> + * Copyright (c) 2012, Intel Corporation
> + * Copyright (c) 2015, Red Hat, Inc.
> + * Copyright (c) 2015, 2016 Linaro Ltd.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +
> +#define pr_fmt(fmt) "ACPI: SPCR: " fmt
> +
> +#include <linux/acpi.h>
> +#include <linux/console.h>
> +#include <linux/kernel.h>
> +#include <linux/serial_core.h>
> +#include <linux/of_fdt.h>
> +
> +static bool earlycon_init_is_deferred __initdata;
> +
> +void __init defer_earlycon_init(void)
> +{
> + earlycon_init_is_deferred = true;
> +}
> +
> +/**
> + * parse_spcr() - parse ACPI SPCR table and add preferred console
> + *
> + * For the architectures with support for ACPI, CONFIG_ACPI_SPCR_TABLE may be
> + * defined to parse ACPI SPCR table. As a result of the parsing preferred
> + * console is registered.
> + *
> + * When CONFIG_ACPI_SPCR_TABLE is defined, this function should should be called
> + * from arch inintialization code as soon as the DT/ACPI decision is made.
> + *
> + * When CONFIG_ACPI_SPCR_TABLE is defined, "earlycon" without parameters in
> + * command line does not start DT earlycon immediately, instead it defers
> + * starting it until DT/ACPI decision is made. If ACPI is enabled at that time,
> + * parse_spcr() parses the table, adds preferred console and sets up it as an
> + * earlycon. If ACPI is disabled at that time, it tries to set up earlycon
> + * from DT.
> + */
> +int __init parse_spcr(void)
> +{
> +#define OPTS_LEN 64
I'm not sure if you need that symbol.
ISTR that sizeof(opts) will give you the size of the array (but maybe I'm
confusing this with something else).
> + static char opts[OPTS_LEN];
> + struct acpi_table_spcr *table;
> + acpi_size table_size;
> + acpi_status status;
> + char *uart;
> + char *iotype;
> + int baud_rate;
> + int err;
> +
> + if (acpi_disabled)
> + return earlycon_init_is_deferred ?
> + early_init_dt_scan_chosen_stdout() : 0;
I would prefer this to be arranged differently, so a specific error value is
returned when ACPI is disabled and the the fallback to DT happens in the
caller (if it cares about DT, that is).
> +
> + status = acpi_get_table_with_size(ACPI_SIG_SPCR, 0,
> + (struct acpi_table_header **)&table,
> + &table_size);
> +
> + if (ACPI_FAILURE(status))
> + return -ENOENT;
> +
> + if (table->header.revision < 2) {
> + err = -EINVAL;
Why -EINVAL?
> + pr_err("wrong table version\n");
> + goto done;
> + }
> +
> + iotype = (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) ?
The parens are not necessary.
Thanks,
Rafael