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  1. 21 Nov, 2018 25 commits
  3. 20 Nov, 2018 1 commit
  5. 19 Nov, 2018 3 commits
  7. 15 Nov, 2018 3 commits
    • Maciej W. Rozycki's avatar
      MIPS: SiByte: Enable swiotlb for SWARM, LittleSur and BigSur · e4849aff
      Maciej W. Rozycki authored 
      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 cce335ae ("[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: default avatarMaciej W. Rozycki <macro@linux-mips.org>
[paul.burton@mips.com: Remove GPL text from dma.c; SPDX tag covers it]
Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Patchwork: https://patchwork.linux-mips.org/patch/21108/
References: cce335ae ("[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
      e4849aff
    • Maciej W. Rozycki's avatar
      MIPS: SiByte: Enable ZONE_DMA32 for LittleSur · 756d6d83
      Maciej W. Rozycki authored 
      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 cce335ae ("[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: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Patchwork: https://patchwork.linux-mips.org/patch/21107/
Fixes: cce335ae ("[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
      756d6d83
    • Maciej W. Rozycki's avatar
      MIPS: SiByte: Set 32-bit bus mask for BCM1250 PCI · 3747b9d6
      Maciej W. Rozycki authored 
      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: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Reviewed-by: default avatarChristoph 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
      3747b9d6
  9. 12 Nov, 2018 4 commits
  11. 10 Nov, 2018 3 commits
  13. 09 Nov, 2018 1 commit
    • Paul Burton's avatar
      MIPS: Avoid using .set mips0 to restore ISA · 378ed6f0
      Paul Burton authored 
      We currently have 2 commonly used methods for switching ISA within
assembly code, then restoring the original ISA.

  1) Using a pair of .set push & .set pop directives. For example:

     .set	push
     .set	mips32r2
     <some_insn>
     .set	pop

  2) Using .set mips0 to restore the ISA originally specified on the
     command line. For example:

     .set	mips32r2
     <some_insn>
     .set	mips0

Unfortunately method 2 does not work with nanoMIPS toolchains, where the
assembler rejects the .set mips0 directive like so:

     Error: cannot change ISA from nanoMIPS to mips0

In preparation for supporting nanoMIPS builds, switch all instances of
method 2 in generic non-platform-specific code to use push & pop as in
method 1 instead. The .set push & .set pop is arguably cleaner anyway,
and if nothing else it's good to consistently use one method.
Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21037/
Cc: linux-mips@linux-mips.org
      378ed6f0
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