The kernel needs to setup the first two tlbs with pad
which is used for early page allocation which is used
by mapin_ram() to allocate tables for lowmem memory
before memory initialisation is done.
Calculate pad directly from lowmem size.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

r6 stores pointer to ramdisk and shouldn't
be used before it is passed to machine_early_init.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

When u-boot passes control over to Linux it places the Linux command
line between to the end of __init_end. When space between
__init_end and __bss_start is not COMMAND_LINE_SIZE then
the part of cmdline can be lost.
In extreme case if __init_end == __bss_start u-boot can't pass
any cmdline to Linux kernel.

This patch fix this issue by copying cmd line directly to
cmd_line char array which is placed in data section.
Reported-by: NDavid Mc Andrew <david.mcandrew@xilinx.com>
Signed-off-by: NMichal Simek <monstr@monstr.eu>

This patch fix the problem with rootfs on JFFS2 with early printk
console turned on.

The origin version used TLB63 for temporary early printk mapping.
The code expect that kernel is not able to use all 64 TLB entries
till early printk console is remapped by ioremap. After that
temporary mapping on TLB63 is silently lost.
This expectation give the opportunity to have early console pretty
early.

Microblaze systems with JFFS2 rootfs with early printk console turned on
used more than 64 TLB entries before kernel can remap early console.
Based on that kernel does access to bad area because early printk mapping
is rewritten.

This patch introduces tlb_skip variable which dynamically stores number
of skipped TLB entries from the TLB0. skip_tlb=2 means that TLB0 and TLB1
should be skipped.

MICROBLAZE_TLB_SKIP defines how many TLB is skipped at the kernel start.
They can be used for user purpose.

TLB 63 is used for temporary LMB mapping (MICROBLAZE_LMB_TLB_ID).

Also clean TLBLO when kernel starts.

For specific kernel sizes kernel can use just one TLB. Detect this case
and use the second TLB for general purpose.

Change _tlbia function to flush TLB entries from tlb_skip to TLB_SIZE.

Export tlb_skip size through debugfs.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Systems with small amount of memory need to be handled
differently. Linux can't allocate the whole 32MB with two TLBs
because then there is no MMU protection.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Signed-off-by: NMichal Simek <monstr@monstr.eu>

The main reason is bug because of dynamic TLB allocation.
U-BOOT didn't disable dcache and then writing to physical address
from ASM wan't visible for reading through MMU.
Disabling caches and clearing all flags from previous code
is good to do so.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

"la" pseudo instruction is only translation to "addik".
Use directly "addik" which is described in the MB reference guide.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Save 0x1 word to rodata section and remove online value
loading if DTB is passed from bootloader. It saves two
asm instructions in bootup.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Fix msr instructions detection. The current code
just use msrclr for loading msr content and compare
it with proper MSR content. If msrclr is not implemented
r8 contains pc address.
Previous code wanted to use MSR carry bit but if msrclr
wasn't implemented carry wasn't cleared.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Little endian system needs to check OF_DT_HEADER
but it is swapped because it is in big-endian.
Microblaze LE provides lwr instruction which loads
magic number in BIG endian format which can be compared.

There is used the fact that if you write 0x1 as word
and load it as byte then you get for big-endian zero
and 1 for little-endian.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Allow developer to configure memory page size at compile time.
Larger pages can improve performance on some workloads.

Based on PowerPC code.
Signed-off-by: NSteven J. Magnani <steve@digidescorp.com>
Signed-off-by: NMichal Simek <monstr@monstr.eu>

_start is located in .text, which causes mismatch warnings with
machine_early_init() and start_kernel() in .init.text.
Signed-off-by: NSteven J. Magnani <steve@digidescorp.com>
Signed-off-by: NMichal Simek <monstr@monstr.eu>

I forget to change register name in comments.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

TLB size was hardcoded in asm code. This patch brings ability
to change TLB size only in one place. (mmu.h).
Signed-off-by: NMichal Simek <monstr@monstr.eu>

When the system has no lmb bram, main memory should be start from
zero because of microblaze vectors.

DTS fragment could look like:
	DDR2_SDRAM: memory@0 {
		device_type = "memory";
		reg = < 0x0 0x10000000 >;
	} ;

Then you have to setup CONFIG_KERNEL_BASE_ADDR=0 which caused
that kernel physical start address will be zero. On reset vector place
will be jump to 0x100 and on 0x100 starts kernel text.

You have to solve how to load the kernel before cpu starts.
Tested with XMD.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

For copy was used r7 register when CONFIG_CMDLINE_BOOL option
is enabled. But r7 stores pointer to fdt that's why machine_early_init
not detect compiled-in DTB.

I also moved kernel PID setup to have TLB init in one block
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Add a common header file for working with the flattened device tree
data structure and merge the shared data tags used by Microblaze and
PowerPC
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>
Acked-by: NMichal Simek <monstr@monstr.eu>
Acked-by: NStephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Acked-by: NStephen Rothwell <sfr@canb.auug.org.au>

It is more safe to use clear instead of msrset.
We save some instructions too.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

It was necessary to use fourth parameter(r8) in early_printk
to show messages on console.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

It is necessary to zeroed r7 when r7 points to bad
dtb - this caused that we have correct messages
about compiled-in dtb or passing via r7
Signed-off-by: NMichal Simek <monstr@monstr.eu>

I can't clear r7 because if I do it I lose information
where DTB come from.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

If r7 is zero at kernel boot, or does not point to a valid DTB, then
we fall back to a DTB (assumed to be) linked statically in the kernel, instead
of blindly copying bogus cruft into the kernel DTB memory region
Signed-off-by: NJohn Williams <john.williams@petalogix.com>
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Signed-off-by: NMichal Simek <monstr@monstr.eu>

Reviewed-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NStephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Acked-by: NJohn Linn <john.linn@xilinx.com>
Acked-by: NJohn Williams <john.williams@petalogix.com>
Signed-off-by: NMichal Simek <monstr@monstr.eu>