Map unused registers at the end of DMA region at 64 MB to allow PCI masters
to cross the boundary when prefetching data from SDRAM.
Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>
Ideally, the default should be set to 0 and let the EHCI driver turn
it on as needed. This makes USB usable in the mean time.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Here it is... HIGHMEM for the ARM architecture. :-)
If you don't have enough ram for highmem pages to be allocated and still
want to test this, then the cmdline option "vmalloc=" can be used with
a value large enough to force the highmem threshold down.
Successfully tested on a Marvell DB-78x00-BP Development Board with
2 GB of RAM.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
VIPT aliasing caches have issues of their own which are not yet handled.
Usage of discard_old_kernel_data() in copypage-v6.c is not highmem ready,
kmap/fixmap stuff doesn't take account of cache colouring, etc.
If/when those issues are handled then this could be reverted.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
On xsc3, L2 cache ops are possible only on virtual addresses. The code
is rearranged so to have a linear progression requiring the least amount
of pte setups in the highmem case. To protect the virtual mapping so
created, interrupts must be disabled currently up to a page worth of
address range.
The interrupt disabling is done in a way to minimize the overhead within
the inner loop. The alternative would consist in separate code for
the highmem and non highmem compilation which is less preferable.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
The choice is between looping over the physical range and performing
single cache line operations, or to map highmem pages somewhere, as
cache range ops are possible only on virtual addresses.
Because L2 range ops are much faster, we go with the later by factoring
the physical-to-virtual address conversion and use a fixmap entry for it
in the HIGHMEM case.
Possible future optimizations to avoid the pte setup cost:
- do the pte setup for highmem pages only
- determine a threshold for doing a line-by-line processing on physical
addresses when the range is small
Signed-off-by: Nicolas Pitre <nico@marvell.com>
If a machine class has a custom __virt_to_bus() implementation then it
must provide a __arch_page_to_dma() implementation as well which is
_not_ based on page_address() to support highmem.
This patch fixes existing __arch_page_to_dma() and provide a default
implementation otherwise. The default implementation for highmem is
based on __pfn_to_bus() which is defined only when no custom
__virt_to_bus() is provided by the machine class.
That leaves only ebsa110 and footbridge which cannot support highmem
until they provide their own __arch_page_to_dma() implementation.
But highmem support on those legacy platforms with limited memory is
certainly not a priority.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
This is a helper to be used by the DMA mapping API to handle cache
maintenance for memory identified by a page structure instead of a
virtual address. Those pages may or may not be highmem pages, and
when they're highmem pages, they may or may not be virtually mapped.
When they're not mapped then there is no L1 cache to worry about. But
even in that case the L2 cache must be processed since unmapped highmem
pages can still be L2 cached.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Most ARM machines have a non IO coherent cache, meaning that the
dma_map_*() set of functions must clean and/or invalidate the affected
memory manually before DMA occurs. And because the majority of those
machines have a VIVT cache, the cache maintenance operations must be
performed using virtual
addresses.
When a highmem page is kunmap'd, its mapping (and cache) remains in place
in case it is kmap'd again. However if dma_map_page() is then called with
such a page, some cache maintenance on the remaining mapping must be
performed. In that case, page_address(page) is non null and we can use
that to synchronize the cache.
It is unlikely but still possible for kmap() to race and recycle the
virtual address obtained above, and use it for another page before some
on-going cache invalidation loop in dma_map_page() is done. In that case,
the new mapping could end up with dirty cache lines for another page,
and the unsuspecting cache invalidation loop in dma_map_page() might
simply discard those dirty cache lines resulting in data loss.
For example, let's consider this sequence of events:
- dma_map_page(..., DMA_FROM_DEVICE) is called on a highmem page.
--> - vaddr = page_address(page) is non null. In this case
it is likely that the page has valid cache lines
associated with vaddr. Remember that the cache is VIVT.
--> for (i = vaddr; i < vaddr + PAGE_SIZE; i += 32)
invalidate_cache_line(i);
*** preemption occurs in the middle of the loop above ***
- kmap_high() is called for a different page.
--> - last_pkmap_nr wraps to zero and flush_all_zero_pkmaps()
is called. The pkmap_count value for the page passed
to dma_map_page() above happens to be 1, so the page
is unmapped. But prior to that, flush_cache_kmaps()
cleared the cache for it. So far so good.
- A fresh pkmap entry is assigned for this kmap request.
The Murphy law says this pkmap entry will eventually
happen to use the same vaddr as the one which used to
belong to the other page being processed by
dma_map_page() in the preempted thread above.
- The kmap_high() caller start dirtying the cache using the
just assigned virtual mapping for its page.
*** the first thread is rescheduled ***
- The for(...) loop is resumed, but now cached
data belonging to a different physical page is
being discarded !
And this is not only a preemption issue as ARM can be SMP as well,
making the above scenario just as likely. Hence the need for some kind
of pkmap page pinning which can be used in any context, primarily for
the benefit of dma_map_page() on ARM.
This provides the necessary interface to cope with the above issue if
ARCH_NEEDS_KMAP_HIGH_GET is defined, otherwise the resulting code is
unchanged.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Reviewed-by: MinChan Kim <minchan.kim@gmail.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
The kmap virtual area borrows a 2MB range at the top of the 16MB area
below PAGE_OFFSET currently reserved for kernel modules and/or the
XIP kernel. This 2MB corresponds to the range covered by 2 consecutive
second-level page tables, or a single pmd entry as seen by the Linux
page table abstraction. Because XIP kernels are unlikely to be seen
on systems needing highmem support, there shouldn't be any shortage of
VM space for modules (14 MB for modules is still way more than twice the
typical usage).
Because the virtual mapping of highmem pages can go away at any moment
after kunmap() is called on them, we need to bypass the delayed cache
flushing provided by flush_dcache_page() in that case.
The atomic kmap versions are based on fixmaps, and
__cpuc_flush_dcache_page() is used directly in that case.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
This is the minimum fixmap interface expected to be implemented by
architectures supporting highmem.
We have a second level page table already allocated and covering
0xfff00000-0xffffffff because the exception vector page is located
at 0xffff0000, and various cache tricks already use some entries above
0xffff0000. Therefore the PTEs covering 0xfff00000-0xfffeffff are free
to be used.
However the XScale cache flushing code already uses virtual addresses
between 0xfffe0000 and 0xfffeffff.
So this reserves the 0xfff00000-0xfffdffff range for fixmap stuff.
The Documentation/arm/memory.txt information is updated accordingly,
including the information about the actual top of DMA memory mapping
region which didn't match the code.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Since now ipaq_model_ops used only for accessing h3600 EGPIOs,
drop it completely and use assign_h3600_egpio() directly.
Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Replace all occurences with assign_h3600_egpio.
Also simplify code a bit by replacing couple of if-else
statements with one-line equivalents.
Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Remove unused fields and associated funtions-accesors.
Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Right now iPaq h3600's default MTD partitions table is a mess. It has
two #ifdefs with #else, giving total 3 variants, depending on your
kernel config. Replace all this with simple two-partitions scheme
(bootloader + rootfs), that used by both shipped WindowsCE and
most of the linux distributions (Familiar, Angstrom)
Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There's no actual code for iPAQ sleeves support in kernel that depends
on this config option.
Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds basic support for Dave/DENX QongEVB-LITE i.MX31-based
board. It includes support for clocks initialization, UART1, NOR-flash,
FPGA-attached NAND flash and DNET ethernet controller (inside FPGA).
Signed-off-by: Ilya Yanok <yanok@emcraft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This patch adds clkdev support for i.MX31. This is done in a
similar way done previously for i.MX27
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
The UART3 had a copy-paste bug. instead of claiming rxd, txd, rts and
cts pins, cts and rts were claimed twice
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
On MX31 we can't do much without mapping the AIPS1/2 register space.
Move these mappings from individual boards to plat-mxc/mm.c
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
The i.MX35 basically features the same peripherals as the i.MX31 with
some differences:
- The i.MX35 has a FEC ethernet controller
- The NAND controller base addresses are different
- The i.MX35 has only 3 UARTs
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This patch adds clock support for i.MX35 SoCs. We do not support setting
of clock rates yet, but most interesting clock rates should be reported.
I couldn't test all clock rates and the datasheet contains some obvious
bugs, so expect some bugs in this code.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
We had hardcoded cpu_is_ macros for mxc architectures till now. As we
want to run the same kernel on i.MX31 and i.MX35 this patch adds cpu_is_
macros which expand to 0 or 1 if only one architecture is compiled in and
only check for the cpu type if more than one architecture is compiled
in.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This patch moves the stuff common to i.MX31 and i.MX35 to mx3x.h and the
specifics to mx31.h/mx35.h. We can build a kernel which runs on i.MX31 and
i.MX35, so always include mx31.h and mx35.h
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
The var->hsync_len, var->right_margin and var->left_margin fields
should contain the real values, not the hardware dependent values.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This adds the dma (ipu_dma) and fb devices for the mx31 for which drivers now are
available.
v2: merge the ipu and fb device in the same patch as suggested by Sascha
Signed-off-by: Valentin Longchamp <valentin.longchamp@epfl.ch>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This enables our mx31moboard to be used on the different baseboards that
we are developping according to the application needs. There are not
many differences between the boards for now, but when other peripherals
are available for mx31 the differences are going to grow.
v2: takes Sascha's comments into account
Signed-off-by: Valentin Longchamp <valentin.longchamp@epfl.ch>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Make sure not to create spurious pulses on GPIOs, when configuring them as
output: first set required level, then switch direction.
Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
