Commit graph

10064 commits

Author SHA1 Message Date
Stepan Moskovchenko
0720d1f052 msm: Add MSM IOMMU support
Add support for the IOMMUs found on the upcoming Qualcomm
MSM8x60 chips. These IOMMUs allow virtualization of the
address space used by most of the multimedia cores on these
chips.

Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:50 -07:00
Gregory Bean
69b7f6ff85 msm: add MSM8x60 FFA support
The MSM8X60 FFA contains different components than the MSM8X60 SURF,
and therefore requires a different ARCH type and machine ID.

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:49 -07:00
Steve Muckle
57bbf1cc8c msm: MSM8X60 simulator board support
Board configuration for MSM8X60 simulation.

Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:48 -07:00
Steve Muckle
49b76f718d msm: add msm8x60_surf machine
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:47 -07:00
Jeff Ohlstein
998ba079fe msm: physical offset for MSM8X60
The MSM8x60 has a different physical memory offset than other targets.

Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:46 -07:00
Abhijeet Dharmapurikar
e4fbb68f45 msm: 8x60: setup correct handlers for private interrupts
Private Peripheral interrupts could be edge triggered or level triggered
depending on the platform. Initialize handlers for these in board file.

Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:45 -07:00
Jeff Ohlstein
569fb6e3e6 msm: add build support for msm8x60 target
Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:44 -07:00
Daniel Walker
46fe5f29e3 msm: allow uart to be conditionally disabled
Some MSM targets don't select the debug UART in this way. For those we
need to disable this selection mechanism.

Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:43 -07:00
Daniel Walker
4ca06de368 msm: dma: add stub functions for dma features not yet present on 8x60
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:42 -07:00
Jeff Ohlstein
871c94a861 msm: clock: add dummy clock driver
Need to add this until real clock support for 8x60 goes in, or else some
drivers won't compile.

Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:41 -07:00
Steve Muckle
9161d303af msm: 8x60: gic initialization fixup for RUMI
On RUMI platform STIs are not enabled by default, contrary to the
GIC spec. The bits for STIs in the enable/enable clear registers
are also RW instead of RO. STIs need to be enabled at initialization
time.

Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:40 -07:00
Steve Muckle
f880c5649e msm: irq: rename existing entry-macro to entry-macro-vic
The existing MSM irq entry macro is specific to a VIC
implementation. Renaming this makes room for irq support based on
other interrupt controllers.

Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:38 -07:00
Steve Muckle
a55df6edcf msm: MSM8X60 RUMI3 board support
Board configuration for MSM8X60 emulation on RUMI3.

Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:37 -07:00
Jeff Ohlstein
672039f035 msm: timer: support 8x60 timers
Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:36 -07:00
Abhijeet Dharmapurikar
01eb4f5c77 msm: irqs-8x60: interrupt map
Define the interrupt map in irq-8x60.h

Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:35 -07:00
Steve Muckle
ed1f31b4b7 msm: initial irq definitions for MSM8X60
IRQ assignments are different for MSM8X60 than other existing MSMs.

Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:34 -07:00
Steve Muckle
6cf6dfefe1 msm: io: MSM8X60 io support
MSM8X60 has different IO mappings than previous MSMs.

Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:33 -07:00
Steve Muckle
c8aabaeb52 msm: create config option for proc-comm
Some builds may not support the proc-comm interface with
the baseband processor.

Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-08 15:12:32 -07:00
Gregory Bean
5d73c53b78 msm: qsd8x50: enable ethernet.
Configure the smc91x ethernet chip on the qsd8x50 SURF.

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-06 09:01:20 -07:00
Gregory Bean
26cc666071 msm: gpio: Add gpiomux calls to request and free.
Add gpiomux get and put calls to msmgpio request and free,
in order to allow gpio lines to be properly reference-counted
and power-managed.

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-06 09:01:19 -07:00
Gregory Bean
2783cc265c msm: add gpio driver for single-core SoCs.
Install a gpiolib driver supporting the on-chip gpios for
single-core MSMs in the 7x00 family, including 7x00A, 7x25, 7x27,
7x30, 8x50, and 8x50a.

As part of the ongoing effort to converge on a common code base,
this driver is based on the Google-Android msmgpio driver, whose
authors include Brian Swetland and Arve Hjønnevåg.

Cc: Arve Hjønnevåg <arve@android.com>
Cc: H Hartley Sweeten <hartleys@visionengravers.com>
Cc: Ryan Mallon <ryan@bluewatersys.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-06 09:01:19 -07:00
Gregory Bean
ab78cde589 msm: Featurize gpiomux.
Featurize gpiomux so that systems like 7x00 which do not wish to use it
do not have to be saddled with the configuration tables.

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-06 09:01:18 -07:00
Gregory Bean
10c4580e79 msm: gpio: Remove tlmm routines obsoleted by gpiomux.
Now that all supported gpio_tlmm_config-using boards
are using gpiomux, remove the deprecated code.

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-06 09:01:17 -07:00
Gregory Bean
224f6de46a msm: convert 7x30 to gpiomux.
Change deprecated gpio_tlmm_config calls to gpiomux calls.

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-06 09:01:17 -07:00
Gregory Bean
dd22b8f703 msm: convert 8x50 to gpiomux.
Change the gpio-init code from deprecated gpio_tlmm_config
to the new gpiomux api.

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-06 09:01:16 -07:00
Gregory Bean
1963a2afc8 msm: add gpiomux api for gpio multiplex & configuration.
Add the 'gpiomux' api, which addresses the following shortcomings
of existing tlmm api:

- gpio power-collapse, which is managed by a peripheral processor on
  other targets, must be managed by the application processor on the 8x60.
- The enable/disable flag of the legacy gpio_tlmm_config api
  is not applicable on the 8x60, and causes confusion.
- The gpio 'direction' bits are meaningless for all func_sel
  configurations except for generic-gpio mode (func_sel 0), in which
  case the gpio_direction_* functions should be used.  Having these
  bits in the tlmm api leads to confusion and misuse of the gpiolib
  api, and they have been removed in gpiomux.
- The functional api of the legacy system ran contrary to the typical
  use-case, which is a single massive configuration at boot.  Rather
  than forcing hundreds of 'config' function calls, the new api
  allows data to be configured with a single table.

gpiomux_get and gpiomux_put are meant to be called automatically
when gpio_request and gpio_free are called, giving automatic
gpiomux/tlmm control to those drivers/lines with simple
power profiles - in the simplest cases, an entry in the gpiomux table
and the correct usage of gpiolib is all that is required to get proper
gpio power control.

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-06 09:01:15 -07:00
Abhijeet Dharmapurikar
846afbd1fe GIC: Dont disable INT in ack callback
Masking in the ack callback fails to work with handle_percpu_irq and handle_edge_irq.
The interrupt stays disabled after the first invocation since percpu and edge irq do
not unmask an interrupt after handling it. For handle_level_irq masking in the ack
is redundant because ack is always called after mask in the mask_ack function.

Masking in the ack function is required only when __do_IRQ was used instead of flow
handlers, but using __do_IRQ has been deprecated.

Remove the masking of interrupt from the ack callback.

Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
2010-10-06 08:39:53 -07:00
Linus Torvalds
f1c9c9797a Merge branch 's5p-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung
* 's5p-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung:
  ARM: S3C64XX: Add IORESOURCE_IRQ_HIGHLEVEL flag to dm9000 on mach-real6410
  ARM: S3C64XX: Fix coding style errors on mach-real6410
  ARM: S3C64XX: Prototype SPI devices
  ARM: S3C64XX: Fix dev-spi build
  ARM: SAMSUNG: Fix on s5p_gpio_[get,set]_drvstr
  ARM: SAMSUNG: Fix on drive strength value
  ARM: S5PV210: Add FIMC clocks
  ARM: S5PV210: Reduce the iodesc length of systimer
  ARM: S5PV210: Update I2C-1 Clock Register Property.
  ARM: S5P: Decrease IO Registers memory region size on FIMC
  ARM: S5P: Fix DMA coherent mask for FIMC
2010-09-19 11:05:05 -07:00
Darius Augulis
4d89ecaae9 ARM: S3C64XX: Add IORESOURCE_IRQ_HIGHLEVEL flag to dm9000 on mach-real6410
Add IORESOURCE_IRQ_HIGHLEVEL irq flag to dm9000 driver
platform data in board mach-real6410.

Signed-off-by: Darius Augulis <augulis.darius@gmail.com>
[kgene.kim@samsung.com: minor title fix]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-09-18 09:54:55 +09:00
Darius Augulis
591cd25ee3 ARM: S3C64XX: Fix coding style errors on mach-real6410
Fix errors reported by checkpatch.pl script

Signed-off-by: Darius Augulis <augulis.darius@gmail.com>
[kgene.kim@samsung.com: minor title fix]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-09-18 09:54:55 +09:00
Mark Brown
5343795fda ARM: S3C64XX: Prototype SPI devices
Avoids build warnings due to the undeclared non-statics.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-09-18 09:54:54 +09:00
Al Viro
653d48b221 arm: fix really nasty sigreturn bug
If a signal hits us outside of a syscall and another gets delivered
when we are in sigreturn (e.g. because it had been in sa_mask for
the first one and got sent to us while we'd been in the first handler),
we have a chance of returning from the second handler to location one
insn prior to where we ought to return.  If r0 happens to contain -513
(-ERESTARTNOINTR), sigreturn will get confused into doing restart
syscall song and dance.

Incredible joy to debug, since it manifests as random, infrequent and
very hard to reproduce double execution of instructions in userland
code...

The fix is simple - mark it "don't bother with restarts" in wrapper,
i.e. set r8 to 0 in sys_sigreturn and sys_rt_sigreturn wrappers,
suppressing the syscall restart handling on return from these guys.
They can't legitimately return a restart-worthy error anyway.

Testcase:
	#include <unistd.h>
	#include <signal.h>
	#include <stdlib.h>
	#include <sys/time.h>
	#include <errno.h>

	void f(int n)
	{
		__asm__ __volatile__(
			"ldr r0, [%0]\n"
			"b 1f\n"
			"b 2f\n"
			"1:b .\n"
			"2:\n" : : "r"(&n));
	}

	void handler1(int sig) { }
	void handler2(int sig) { raise(1); }
	void handler3(int sig) { exit(0); }

	main()
	{
		struct sigaction s = {.sa_handler = handler2};
		struct itimerval t1 = { .it_value = {1} };
		struct itimerval t2 = { .it_value = {2} };

		signal(1, handler1);

		sigemptyset(&s.sa_mask);
		sigaddset(&s.sa_mask, 1);
		sigaction(SIGALRM, &s, NULL);

		signal(SIGVTALRM, handler3);

		setitimer(ITIMER_REAL, &t1, NULL);
		setitimer(ITIMER_VIRTUAL, &t2, NULL);

		f(-513); /* -ERESTARTNOINTR */

		write(1, "buggered\n", 9);
		return 1;
	}

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-17 10:22:18 -07:00
Mark Brown
23a07eb0e8 ARM: S3C64XX: Fix dev-spi build
The irqs.h usage here got missed in the Samsung platform reorganisation.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-09-14 17:59:51 +09:00
Kukjin Kim
cbd2780fce ARM: SAMSUNG: Fix on s5p_gpio_[get,set]_drvstr
This patch fixes bug on gpio drive strength helper function.

The offset should be like follwoing.
-       off = chip->chip.base - pin;
+       off = pin - chip->chip.base;

In the s5p_gpio_get_drvstr(),
the second line is unnecessary, because overwrite drvstr.
        drvstr = __raw_readl(reg);
-       drvstr = 0xffff & (0x3 << shift);

And need 2bit masking before return the drvstr value.
        drvstr = drvstr >> shift;
+       drvstr &= 0x3;

In the s5p_gpio_set_drvstr(), need relevant bit clear.
        tmp = __raw_readl(reg);
+       tmp &= ~(0x3 << shift);
        tmp |= drvstr << shift;

Reported-by: Jaecheol Lee <jc.lee@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-09-14 17:59:31 +09:00
Kukjin Kim
0770e5280e ARM: SAMSUNG: Fix on drive strength value
This patch fixes on defined drive strength value for GPIO.
According to data sheet, if we want drive strength 1x, the value
should be 00(b), if 2x should be 10(b), if 3x should be 01(b),
and if 4x should be 11(b). Also fixes comment(from S5C to S5P).

Reported-by: Janghyuck Kim <janghyuck.kim@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-09-14 17:59:23 +09:00
Marek Szyprowski
da01c2f733 ARM: S5PV210: Add FIMC clocks
These clocks enables FIMC driver to operate on machines, which
bootloader power gated FIMC devices to save power on boot.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
[kgene.kim@samsung.com: minor title fix]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-09-14 17:59:16 +09:00
Kyungmin Park
a203a13a88 ARM: S5PV210: Reduce the iodesc length of systimer
It's enough to use 4KiB.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-09-14 17:58:35 +09:00
MyungJoo Ham
f1c894de47 ARM: S5PV210: Update I2C-1 Clock Register Property.
CLK_GATE_IP3[8] is RESERVED. The port "I2C_HDMI_DDC" of CLK_GATE_IP3[10] is
used as another I2C port. Therefore, defined the unused I2C-1 as another I2C
there was left undefined but used.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-09-14 17:58:21 +09:00
Sylwester Nawrocki
80e2f36aab ARM: S5P: Decrease IO Registers memory region size on FIMC
IO registers region size of all FIMC versions is less than 1kB so there
is no need to reserve 1M.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
[kgene.kim@samsung.com: minor title fix]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-09-14 17:57:55 +09:00
Marek Szyprowski
0fe7f88504 ARM: S5P: Fix DMA coherent mask for FIMC
FIMC driver uses DMA_coherent allocator, which requires proper dma mask
to be set.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
[kgene.kim@samsung.com: minor title fix]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-09-14 17:57:39 +09:00
Linus Torvalds
6ccaa31729 Merge branch 'at91-fixes-for-linus' of git://github.com/at91linux/linux-2.6-at91
* 'at91-fixes-for-linus' of git://github.com/at91linux/linux-2.6-at91:
  AT91: at91sam9261ek: remove C99 comments but keep information
  AT91: at91sam9261ek board: remove warnings related to use of SPI or SD/MMC
  AT91: dm9000 initialization update
  AT91: SAM9G45 - add a separate clock entry for every single TC block
  AT91: clock: peripheral clocks can have other parent than mck
  AT91: change dma resource index
2010-09-10 07:24:51 -07:00
Nicolas Ferre
4deb22a600 AT91: at91sam9261ek: remove C99 comments but keep information
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
2010-09-10 14:36:06 +02:00
Nicolas Ferre
64d72bbeeb AT91: at91sam9261ek board: remove warnings related to use of SPI or SD/MMC
The sd/mmc data structure is not used if SPI is selected. The configuration
of PIO on the board prevent from using both interfaces at the same time
(board dependent).
Remove the warnings at compilation time adding a preprocessor condition.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
2010-09-10 12:00:56 +02:00
Nicolas Ferre
1879c45cce AT91: dm9000 initialization update
Add information in dm9000 mac/phy chip initialization:
- irq resource details
- platform data details

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
2010-09-10 11:39:23 +02:00
Russell King
a14d040408 ARM: Update mach-types
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-09-09 22:49:26 +01:00
Russell King
9e84ed63dc ARM: Partially revert "Auto calculate ZRELADDR and provide option for exceptions"
Partially revert e69edc7, which introduced automatic zreladdr
support.  The change in the way the manual definition is defined
seems to be error and conflict prone.  Go back to the original way
we were handling this for the time being, while keeping the automatic
zreladdr facility.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-09-09 22:39:41 +01:00
Russell King
de9ea203d1 Merge branch 'origin' 2010-09-09 22:38:43 +01:00
Fabian Godehardt
ab64511cbb AT91: SAM9G45 - add a separate clock entry for every single TC block
Without this patch you will not be able to register the first block
because of the second association call on at91_add_device_tc().

Signed-off-by: Fabian Godehardt <fg@emlix.com>
[nicolas.ferre@atmel.com: change tcb1_clk to fake child clock of tcb0_clk]
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
2010-09-09 20:14:43 +02:00
Nicolas Ferre
5afddee415 AT91: clock: peripheral clocks can have other parent than mck
While registering clock allow to set parent clock other
than mck. It is useful for clocks than can be seen as
child clock of a peripheral.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
2010-09-09 20:13:23 +02:00
Russell King
2be23c475a ARM: Ensure PTE modifications via dma_alloc_coherent are visible
Dave Hylands reports:
| We've observed a problem with dma_alloc_writecombine when the system
| is under heavy load (heavy bus traffic).  We've managed to reduce the
| problem to the following snippet, which is run from a kthread in a
| continuous loop:
|
|   void *virtAddr;
|   dma_addr_t physAddr;
|   unsigned int numBytes = 256;
|
|   for (;;) {
|       virtAddr = dma_alloc_writecombine(NULL,
|             numBytes, &physAddr, GFP_KERNEL);
|       if (virtAddr == NULL) {
|          printk(KERN_ERR "Running out of memory\n");
|          break;
|       }
|
|       /* access DMA memory allocated */
|       tmp = virtAddr;
|       *tmp = 0x77;
|
|       /* free DMA memory */
|       dma_free_writecombine(NULL,
|             numBytes, virtAddr, physAddr);
|
|         ...sleep here...
|     }
|
| By itself, the code will run forever with no issues. However, as we
| increase our bus traffic (typically using DMA) then the *tmp = 0x77
| line will eventually cause a page fault. If we add a small delay (a
| few microseconds) before the *tmp = 0x77, then we don't see a page
| fault, even under heavy load.

A dsb() is required after modifying the PTE entries to ensure that they
will always be visible.  Add this dsb().

Reported-by: Dave Hylands <dhylands@gmail.com>
Tested-by: Dave Hylands <dhylands@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-09-08 16:27:56 +01:00