Some platforms gate the pclk (APB - the bus - clock) to the peripherals
for power saving, along with the functional clock. When devices are
accessed without pclk enabled, the kernel will oops.
This gives them two options:
1. Leave all clocks on all the time.
2. Attempt to gate pclk along with the functional clock.
(With some hardware, pclk and the functional clock are gated by a single
bit in a register.)
(1) has the disadvantage that it causes increased power usage, which is
bad news for battery operated devices. (2) can lead to kernel oops if
registers are accessed without the functional clock being enabled.
So, introduce the apb_pclk signal in such a way existing drivers don't
need to be updated. Essentially, this means we guarantee that:
1. pclk will be enabled whenever the driver is bound to a device -
from probe() to remove() time.
2. pclk will also be enabled when reading the primecell IDs from the device.
In order to allow drivers to be incrementally updated to achieve greater
power savings, we provide two additional calls to allow drivers to
manage the pclk - amba_pclk_enable()/amba_pclk_disable().
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch modifies the amba bus detection logic in the kernel
to detect the AMBA devices using the calculated resource
size information rather than the hard coded 4K size.
It also calculates the resource size when request mem region
and release mem region.
Signed-off-by: Leo Chen <leochen@broadcom.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
AMBA device resources were being reported as:
10004000-10004fff : <BAD>
This is because dev_name() was returning NULL prior to device_register.
Ensure that the struct device is properly initialized, and the name is
set before adding it to the device tree.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arch/arm/mach-realview/platsmp.c:140: error: 'jiffies' undeclared (first use in this function)
drivers/amba/bus.c:246: error: 'NO_IRQ' undeclared (first use in this function)
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This changes the uevent buffer functions to use a struct instead of a
long list of parameters. It does no longer require the caller to do the
proper buffer termination and size accounting, which is currently wrong
in some places. It fixes a known bug where parts of the uevent
environment are overwritten because of wrong index calculations.
Many thanks to Mathieu Desnoyers for finding bugs and improving the
error handling.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Make use of add_uevent_var() instead of (often incorrectly) open coding it.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Eric Rannaud <eric.rannaud@gmail.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix driver model __must_check warnings in drivers/bus/amba.c by
rearranging how we add attributes to devices.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This is needed if we wish to change the size of the resource structures.
Based on an original patch from Vivek Goyal <vgoyal@in.ibm.com>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Many ARM drivers do not need to include asm/irq.h - remove this
unnecessary include from some ARM drivers.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
