cn58xx is compatible with cn50xx, so use the latter.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
[paul.burton@mips.com: s/cn52xx/cn50xx/ in commit message.]
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
cvmx_gpio_bit_cfgx bitfields are indentical on cn70xx and cn73xx,
and also match the default definition. So use that instead.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Enable all OCTEON drivers in defconfig. Currently oct_ilm and octeon-rng
are still missing; enable those to get them included in kernel builds.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
There is a plan to build the kernel with -Wimplicit-fallthrough and
these places in the code produced warnings. Fix them up.
This patch produces no change in behaviour, but should be reviewed in
case these are actually bugs not intentional fallthoughs.
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Kees Cook <keescook@google.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
In the same vein as commit 93e01942a6 ("MIPS: Hardcode cpu_has_* where
known at compile time due to ISA"), we can use our knowledge of the ISA
being targeted by the kernel build to make cpu_has_mips* macros
compile-time constant in some cases. This allows the compiler greater
opportunity to optimize out code which will never execute.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21245/
Cc: linux-mips@linux-mips.org
The "norps" kernel command line parameter has apparently been deprecated
ever since it was added to the kernel back in 2006 - all it does is
print a message telling the user to use something else.
Remove the long dead "norps" parameter.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21244/
Cc: linux-mips@linux-mips.org
MIPS' asm/mmzone.h includes the machine/platform mmzone.h
unconditionally, but since commit bb53fdf395 ("MIPS: c-r4k: Add
r4k_blast_scache_node for Loongson-3") is included by asm/rk4cache.h for
all r4k-style configs regardless of CONFIG_NEED_MULTIPLE_NODES.
This is problematic when CONFIG_NEED_MULTIPLE_NODES=n because both the
loongson3 & ip27 mmzone.h headers unconditionally define the NODE_DATA
preprocessor macro which is aready defined by linux/mmzone.h, resulting
in the following build error:
In file included from ./arch/mips/include/asm/mmzone.h:10,
from ./arch/mips/include/asm/r4kcache.h:23,
from arch/mips/mm/c-r4k.c:33:
./arch/mips/include/asm/mach-loongson64/mmzone.h:48: error: "NODE_DATA" redefined [-Werror]
#define NODE_DATA(n) (&__node_data[(n)]->pglist)
In file included from ./include/linux/topology.h:32,
from ./include/linux/irq.h:19,
from ./include/asm-generic/hardirq.h:13,
from ./arch/mips/include/asm/hardirq.h:16,
from ./include/linux/hardirq.h:9,
from arch/mips/mm/c-r4k.c:11:
./include/linux/mmzone.h:907: note: this is the location of the previous definition
#define NODE_DATA(nid) (&contig_page_data)
Resolve this by only including the machine mmzone.h when
CONFIG_NEED_MULTIPLE_NODES=y, which also removes the need for the empty
mach-generic version of the header which we delete.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Fixes: bb53fdf395 ("MIPS: c-r4k: Add r4k_blast_scache_node for Loongson-3")
Select CONFIG_HAVE_LD_DEAD_CODE_DATA_ELIMINATION for MIPS, allowing the
user to enable dead code elimination. In order for this to work, ensure
that we keep the data bus exception table & the machine list by
annotating them with KEEP.
This shrinks both 32r2el_defconfig & 64r6el_defconfig builds by ~6%, as
shown by numbers from scripts/bloat-o-meter:
| 32r2el_defconfig | 64r6el_defconfig
--------|------------------|------------------
No DCE | 8919864 | 8286307
DCE | 8338988 (-6.51%) | 7741808 (-6.57%)
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21187/
Cc: linux-mips@linux-mips.org
If we are about to return the same register address that would
be the default anyway, fallback to default return instead of adding
a case label.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21200/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
When register definition is identical on all OCTEONs, we can trivially
delete the model specific union fields.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21203/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Delete cmvx override functions, they are not used.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21196/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Make cvmx_bootmem_alloc_range() static, it's not used outside the file.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21195/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Make cvmx_helper_setup_red_queue static, it's not used outside this file.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21194/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Include linux/sched/clock.h to get the declaration for sched_clock().
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21189/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Use correct type for fdt_property nameoff field.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21204/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Make __cvmx_helper_errata_fix_ipd_ptr_alignment static, it's not used
outside the file.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21210/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Include arm/prom.h to get the declaration of device_tree_init().
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21202/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Include asm/fw/fw.h to get the declaration of fw_init_cmdline().
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21206/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Make some internal data and functions static to avoid sparse warnings.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21211/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Make cvmx_l2c_spinlock static, it's not used outside the file.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21209/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Remove the Malta display platform code in favour of probing the
img-ascii-lcd driver via device tree. This reduces the amount of
platform code & the img-ascii-lcd driver offers us advantages in terms
of code sharing with other boards & functionality such as changing the
displayed message via sysfs. Defconfigs are untouched because the driver
already defaults y on when CONFIG_MIPS_MALTA=y.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21182/
Cc: linux-mips@linux-mips.org
The current methods for obtaining FP context via ptrace only provide
either 32 or 64 bits per data register. With MSA, where vector registers
are aliased with scalar FP data registers, those registers are 128 bits
wide. Thus a new mechanism is required for userland to access those
registers via ptrace. This patch introduces an NT_MIPS_MSA regset which
provides, in this order:
- The full 128 bits value of each vector register, in native
endianness saved as though elements are doubles. That is, the format
of each vector register is as would be obtained by saving it to
memory using an st.d instruction.
- The 32 bit scalar FP implementation register (FIR).
- The 32 bit scalar FP control & status register (FCSR).
- The 32 bit MSA implementation register (MSAIR).
- The 32 bit MSA control & status register (MSACSR).
The provision of the FIR & FCSR registers in addition to the MSA
equivalents allows scalar FP context to be retrieved as a subset of
the context available via this regset. Along with the MSA equivalents
they also nicely form the final 128 bit "register" of the regset.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21180/
Cc: linux-mips@linux-mips.org
KEXEC needs the new kernel's load address to be aligned on a page
boundary (see sanity_check_segment_list()), but on MIPS the default
vmlinuz load address is only explicitly aligned to 16 bytes.
Since the largest PAGE_SIZE supported by MIPS kernels is 64KB, increase
the alignment calculated by calc_vmlinuz_load_addr to 64KB.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21131/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <james.hogan@mips.com>
Cc: Steven J . Hill <Steven.Hill@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: <stable@vger.kernel.org> # 2.6.36+
This patch is borrowed from ARM64 to ensure pmd_present() returns false
after pmd_mknotpresent(). This is needed for THP.
References: 5bb1cc0ff9 ("arm64: Ensure pmd_present() returns false after pmd_mknotpresent()")
Reviewed-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21135/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <james.hogan@mips.com>
Cc: Steven J . Hill <Steven.Hill@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: <stable@vger.kernel.org> # 3.8+
For multi-node Loongson-3 (NUMA configuration), r4k_blast_scache() can
only flush Node-0's scache. So we add r4k_blast_scache_node() by using
(CAC_BASE | (node_id << NODE_ADDRSPACE_SHIFT)) instead of CKSEG0 as the
start address.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
[paul.burton@mips.com: Include asm/mmzone.h from asm/r4kcache.h for
nid_to_addrbase(). Add asm/mach-generic/mmzone.h
to allow inclusion for all platforms.]
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21129/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <james.hogan@mips.com>
Cc: Steven J . Hill <Steven.Hill@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: <stable@vger.kernel.org> # 3.15+
Select ARCH_HAS_UBSAN_SANITIZE_ALL in order to allow the user to
enable CONFIG_UBSAN_SANITIZE_ALL and instrument the entire kernel for
ubsan checks.
We exclude the VDSO from this because its build doesn't include the
__ubsan_handle_*() functions that the kernel proper defines in from
lib/ubsan.c, and the VDSO would have no sane way to report errors even
if it had definitions of these functions.
Signed-off-by: Hassan Naveed <hnaveed@wavecomp.com>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21179/
Cc: <linux-mips@linux-mips.org>
The Broadcom SiByte BCM1250, BCM1125, and BCM1125H SOCs have an onchip
DRAM controller that supports memory amounts of up to 16GiB, and due to
how the address decoder has been wired in the SOC any memory beyond 1GiB
is actually mapped starting from 4GiB physical up, that is beyond the
32-bit addressable limit[1]. Consequently if the maximum amount of
memory has been installed, then it will span up to 19GiB.
Many of the evaluation boards we support that are based on one of these
SOCs have their memory soldered and the amount present fits in the
32-bit address range. The BCM91250A SWARM board however has actual DIMM
slots and accepts, depending on the peripherals revision of the SOC, up
to 4GiB or 8GiB of memory in commercially available JEDEC modules[2].
I believe this is also the case with the BCM91250C2 LittleSur board.
This means that up to either 3GiB or 7GiB of memory requires 64-bit
addressing to access.
I believe the BCM91480B BigSur board, which has the BCM1480 SOC instead,
accepts at least as much memory, although I have no documentation or
actual hardware available to verify that.
Both systems have PCI slots installed for use by any PCI option boards,
including ones that only support 32-bit addressing (additionally the
32-bit PCI host bridge of the BCM1250, BCM1125, and BCM1125H SOCs limits
addressing to 32-bits), and there is no IOMMU available. Therefore for
PCI DMA to work in the presence of memory beyond enable swiotlb for the
affected systems.
All the other SOC onchip DMA devices use 40-bit addressing and therefore
can address the whole memory, so only enable swiotlb if PCI support and
support for DMA beyond 4GiB have been both enabled in the configuration
of the kernel.
This shows up as follows:
Broadcom SiByte BCM1250 B2 @ 800 MHz (SB1 rev 2)
Board type: SiByte BCM91250A (SWARM)
Determined physical RAM map:
memory: 000000000fe7fe00 @ 0000000000000000 (usable)
memory: 000000001ffffe00 @ 0000000080000000 (usable)
memory: 000000000ffffe00 @ 00000000c0000000 (usable)
memory: 0000000087fffe00 @ 0000000100000000 (usable)
software IO TLB: mapped [mem 0xcbffc000-0xcfffc000] (64MB)
in the bootstrap log and removes failures like these:
defxx 0000:02:00.0: dma_direct_map_page: overflow 0x0000000185bc6080+4608 of device mask ffffffff bus mask 0
fddi0: Receive buffer allocation failed
fddi0: Adapter open failed!
IP-Config: Failed to open fddi0
defxx 0000:09:08.0: dma_direct_map_page: overflow 0x0000000185bc6080+4608 of device mask ffffffff bus mask 0
fddi1: Receive buffer allocation failed
fddi1: Adapter open failed!
IP-Config: Failed to open fddi1
when memory beyond 4GiB is handed out to devices that can only do 32-bit
addressing.
This updates commit cce335ae47 ("[MIPS] 64-bit Sibyte kernels need
DMA32.").
References:
[1] "BCM1250/BCM1125/BCM1125H User Manual", Revision 1250_1125-UM100-R,
Broadcom Corporation, 21 Oct 2002, Section 3: "System Overview",
"Memory Map", pp. 34-38
[2] "BCM91250A User Manual", Revision 91250A-UM100-R, Broadcom
Corporation, 18 May 2004, Section 3: "Physical Description",
"Supported DRAM", p. 23
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
[paul.burton@mips.com: Remove GPL text from dma.c; SPDX tag covers it]
Signed-off-by: Paul Burton <paul.burton@mips.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Patchwork: https://patchwork.linux-mips.org/patch/21108/
References: cce335ae47 ("[MIPS] 64-bit Sibyte kernels need DMA32.")
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
The LittleSur board is marked for high memory support and therefore
clearly must provide a way to have enough memory installed for some to
be present outside the low 4GiB physical address range. With the memory
map of the BCM1250 SOC it has been built around it means over 1GiB of
actual DRAM, as only the first 1GiB is mapped in the low 4GiB physical
address range[1].
Complement commit cce335ae47 ("[MIPS] 64-bit Sibyte kernels need
DMA32.") then and also enable ZONE_DMA32 for LittleSur.
References:
[1] "BCM1250/BCM1125/BCM1125H User Manual", Revision 1250_1125-UM100-R,
Broadcom Corporation, 21 Oct 2002, Section 3: "System Overview",
"Memory Map", pp. 34-38
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Patchwork: https://patchwork.linux-mips.org/patch/21107/
Fixes: cce335ae47 ("[MIPS] 64-bit Sibyte kernels need DMA32.")
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
The Broadcom SiByte BCM1250, BCM1125H and BCM1125 SOCs have an onchip
32-bit PCI host bridge, and the two former SOCs also have an onchip HT
host bridge. The HT host bridge, where present, appears in the PCI
configuration space as if it was a device on the 32-bit PCI bus behind
the PCI host bridge, however at the hardware level its signals are
routed separately, so these two devices are actually peer host bridges.
As documented[1] and observed in reality the 32-bit PCI host bridge does
not support 64-bit addressing as it does not support the Dual Address
Cycle (DAC) PCI command, and naturally, being 32-bit only, it has no
means to carry the high 32 address bits otherwise. However the DRAM
controller also included in the SOC supports memory amounts of up to
16GiB, and due to how the address decoder has been wired in the SOC any
memory beyond 1GiB is actually mapped starting from 4GiB physical up,
that is beyond the 32-bit addressable limit. Consequently if the
maximum amount of memory has been installed, then it will span up to
19GiB.
Contrariwise, the HT host bridge does support full 40-bit addressing
defined by the HyperTransport (formerly LDT) specification the bridge
adheres to, depending on the peripherals revision of the SOC[2] either
revision 0.17[3] or revision 1.03[4]. This allows addressing any and
all memory installed, and well beyond.
Set the bus mask then to limit DMA addressing to 32 bits for all the
devices down the 32-bit PCI host bridge, excluding however any devices
that are down the HT host bridge.
References:
[1] "BCM1250/BCM1125/BCM1125H User Manual", Revision 1250_1125-UM100-R,
Broadcom Corporation, 21 Oct 2002, Section 8: "PCI Bus and
HyperTransport Fabric", "Introduction", p. 190
[2] same, Table 140: "HyperTransport Configuration Header (Type 1)", p.
245
[3] "Lightning Data Transport IO Specification", Revision 0.17, Advanced
Micro Devices, 21 Jan 2000, Section 3.2.1.2 "Command Packet", p. 8
[4] "HyperTransport I/O Link Specification", Revision 1.03,
HyperTransport Technology Consortium, 10 Oct 2001, Section 3.2.1.2
"Request Packet", pp. 27-28
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Patchwork: https://patchwork.linux-mips.org/patch/21106/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
The CPU_NO_EFFICIENT_FFS pre-processor macro is no longer used, with all
architectures toggling the equivalent Kconfig symbol
CONFIG_CPU_NO_EFFICIENT_FFS instead. Remove our check for the unused
macro.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21046/
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Select CONFIG_CPU_NO_EFFICIENT_FFS via Kconfig when the kernel is
configured for a pre-MIPS32r1 CPU, rather than defining its equivalent
in asm/cpu-features.h based upon overrides of cpu_has_mips* macros.
The latter only works if a platform has an cpu-feature-overrides.h
header which defines cpu_has_mips* macros, which are not generally
needed. There are many cases where we know that the target ISA for a
kernel build is MIPS32r1 or later & thus includes the CLZ instruction,
without requiring any overrides from the platform. Using Kconfig allows
us to take those into account, and more naturally make a decision about
instruction support using information about the target ISA.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21045/
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
The Intel EG20T Platform Controller Hub used on the MIPS Boston
development board supports prefetching memory to optimize DMA transfers.
Unfortunately for unknown reasons this doesn't work well with some MIPS
CPUs such as the P6600, particularly when using an I/O Coherence Unit
(IOCU) to provide cache-coherent DMA. In these systems it is common for
DMA data to be lost, resulting in broken access to EG20T devices such as
the MMC or SATA controllers.
Support for a DT property to configure the prefetching was added a while
back by commit 549ce8f134 ("misc: pch_phub: Read prefetch value from
device tree if passed") but we never added the DT snippet to make use of
it. Add that now in order to disable the prefetching & fix DMA on the
affected systems.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21068/
Cc: linux-mips@linux-mips.org
