lkml.org 
[lkml]   [2015]   [Sep]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v3 1/7] acpi: Add early device probing infrastructure
From
Date

Hi Marc,

On 09/28/2015 04:49 PM, Marc Zyngier wrote:
> IRQ controllers and timers are the two types of device the kernel
> requires before being able to use the device driver model.
>
> ACPI so far lacks a proper probing infrastructure similar to the one
> we have with DT, where we're able to declare IRQ chips and
> clocksources inside the driver code, and let the core code pick it up
> and call us back on a match. This leads to all kind of really ugly
> hacks all over the arm64 code and even in the ACPI layer.
>
> In order to allow some basic probing based on the ACPI tables,
> introduce "struct acpi_probe_entry" which contains just enough
> data and callbacks to match a table, an optional subtable, and
> call a probe function. A driver can, at build time, register itself
> and expect being called if the right entry exists in the ACPI
> table.
>
> A acpi_probe_device_table() is provided, taking an identifier for
> a set of acpi_prove_entries, and iterating over the registered
> entries.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> drivers/acpi/scan.c | 39 +++++++++++++++++++++++
> include/asm-generic/vmlinux.lds.h | 10 ++++++
> include/linux/acpi.h | 66 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 115 insertions(+)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index f834b8c..daf9fc8 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -1913,3 +1913,42 @@ int __init acpi_scan_init(void)
> mutex_unlock(&acpi_scan_lock);
> return result;
> }
> +
> +static struct acpi_probe_entry *ape;
> +static int acpi_probe_count;
> +static DEFINE_SPINLOCK(acpi_probe_lock);
> +
> +static int __init acpi_match_madt(struct acpi_subtable_header *header,
> + const unsigned long end)
> +{
> + if (!ape->subtable_valid || ape->subtable_valid(header, ape))
> + if (!ape->probe_subtbl(header, end))
> + acpi_probe_count++;
> +
> + return 0;
> +}
> +
> +int __init __acpi_probe_device_table(struct acpi_probe_entry *ap_head, int nr)
> +{
> + int count = 0;
> +
> + if (acpi_disabled)
> + return 0;
> +
> + spin_lock(&acpi_probe_lock);
> + for (ape = ap_head; nr; ape++, nr--) {
> + if (ACPI_COMPARE_NAME(ACPI_SIG_MADT, ape->id)) {
> + acpi_probe_count = 0;
> + acpi_table_parse_madt(ape->type, acpi_match_madt, 0);

Isn't supposed 'acpi_table_parse_madt' to return the count ? and
shouldn't the return code be checked ?

> + count += acpi_probe_count;
> + } else {
> + int res;
> + res = acpi_table_parse(ape->id, ape->probe_table);
> + if (!res)
> + count++;
> + }
> + }
> + spin_unlock(&acpi_probe_lock);
> +
> + return count;
> +}




--
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog



\
 
 \ /
  Last update: 2015-09-29 07:21    [W:2.076 / U:0.992 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site