MIPS: Loongson64: Enable DMA noncoherent support

There are some Loongson64 systems come with broken coherent DMA
support, firmware will set a bit in boot_param and pass nocoherentio
in cmdline.

However nonconherent support was missed out when spin off Loongson-2EF
form Loongson64, and that boot_param change never made itself into
upstream.

Support DMA noncoherent properly to get those systems working.

Cc: stable@vger.kernel.org
Fixes: 71e2f4dd5a65 ("MIPS: Fork loongson2ef from loongson64")
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Loongson64: Remove a "set but not used" variable

This fix build warning:

arch/mips/loongson64/env.c: In function 'prom_init_env':
>> arch/mips/loongson64/env.c:50:14: warning: variable 'device' set but not used [-Wunused-but-set-variable]
50 | u16 vendor, device;
| ^~~~~~
{standard input}: Assembler messages:
{standard input}:788: Error: found '(', expected: ')'
{standard input}:788: Error: found '(', expected: ')'
{standard input}:788: Error: non-constant expression in ".if" statement
{standard input}:788: Error: junk at end of line, first unrecognized character is `('
{standard input}:801: Error: found '(', expected: ')'
{standard input}:801: Error: found '(', expected: ')'
{standard input}:801: Error: non-constant expression in ".if" statement
{standard input}:801: Error: junk at end of line, first unrecognized character is `('

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Loongson64: Distinguish firmware dependencies DTB/LEFI

Add DTB boot support, only support Loongson-2K1000 processor
for now, determine whether to use the built-in DTB or the DTB
from the firmware by checking the range of CKSEG0 and XKPHYS.
loongson_fw_interface will be used in the future.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Tested-by: Ming Wang <wangming01@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Loongson64: Remove unused sysconf members

We don't need them anymore, They are uniform on all Loongson64 systems
and have been fixed in DeviceTree.loongson3_platform_init is replaced
with DTS + driver.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Acked-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Loongson64: Add /sys/firmware/lefi/boardinfo

Add /sys/firmware/lefi/boardinfo to get mainboard and BIOS info easily
on the Loongson platform, this is useful to point out the current used
mainboard type and BIOS version when there exists problems related with
hardware or firmware.

The related structures are already defined in the interface specification
about firmware and kernel which are common requirement and specific for
Loongson64, so only add a new boardinfo.c file in arch/mips/loongson64.

E.g. with this patch:

[loongson@linux ~]$ cat /sys/firmware/lefi/boardinfo
Board Info
Manufacturer : LEMOTE
Board Name : LEMOTE-LS3A4000-7A1000-1w-V01-pc
Family : LOONGSON3

BIOS Info
Vendor : Kunlun
Version : Kunlun-A1901-V4.1.3-20200414093938
ROM Size : 4 KB
Release Date : 2020-04-14

By the way, using dmidecode command can get the similar info if there
exists SMBIOS in firmware, but the fact is that there is no SMBIOS on
some machines, we can see nothing when execute dmidecode, like this:

[root@linux loongson]# dmidecode
# dmidecode 2.12
# No SMBIOS nor DMI entry point found, sorry.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: KVM: Add kvm guest support for Loongson-3

Loongson-3 KVM guest is based on virtio, it use liointc as its interrupt
controller and use GPEX as the pci controller.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Loongson64: Load LS7A dtbs

Load correct devicetree according to PRID and PCH type.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Loongson: Rename CPU device-tree binding

Loongson-3A R1/R2/R3 and Loongson-3B R1/R2 use the same package naming
in dts, and Loongson-3A R4 will be different. In cpu.h the classic 64bit
Loongson processors are called Loongson64C (C for classic, pre Loongson-
3A R4), and the new 64bit Loongson processors are called Loongson64G (G
for generic, Loongson-3A R4+). To keep consistency and make extensible,
we rename the classic "loongson3" prefix to "loongson64c", and the new
prefix for Loongson-3A R4+ will be "loongson64g".

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Loongson: Add DMA support for LS7A

In the current market, the most used bridge chip on the Loongson platform
are RS780E and LS7A, the RS780E bridge chip is already supported by the
mainline kernel.

If use the default implementation of __phys_to_dma() and __dma_to_phys()
in dma-direct.h when CONFIG_ARCH_HAS_PHYS_TO_DMA is not set, it works
well used with LS7A on the Loongson single-way and multi-way platform,
and also works well used with RS780E on the Loongson single-way platform,
but the DMA address will be wrong on the non-node0 used with RS780E on
the Loongson multi-way platform.

Just as the description in the code comment, the devices get node id from
40 bit of HyperTransport bus, so we extract 2 bit node id (bit 44~45) from
48 bit address space of Loongson CPU and embed it into HyperTransport bus
(bit 37-38), this operation can be done only at the software level used
with RS780E on the Loongson multi-way platform, because it has no hardware
function to translate address of node id, this is a hardware compatibility
problem.

Device
|
| DMA address
|
Host Bridge
|
| HT bus address (40 bit)
|
CPU
|
| physical address (48 bit)
|
RAM

The LS7A has dma_node_id_offset field in the DMA route config register,
the hardware can use the dma_node_id_offset to translate address of
node id automatically, so we can get correct address when just use the
dma_pfn_offset field in struct device.

For the above reasons, in order to maintain downward compatibility
to support the RS780E bridge chip, it is better to use the platform
dependent implementation of __phys_to_dma() and __dma_to_phys().

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Loongson: Get host bridge information

Read the address of host bridge configuration space to get the vendor ID
and device ID of host bridge, and then we can distinguish various types
of host bridge such as LS7A or RS780E.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Loongson64: Load built-in dtbs

Load proper dtb according to firmware passed parameters and
CPU PRID.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Co-developed-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Loongson64: Move files to the top-level directory

Current Loongson-3 code can share among all Loongson64 processors.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: chenhc@lemote.com
Cc: paul.burton@mips.com