[v3,1/8] SOC: brcmstb: add memory API

Commit Message

Jim Quinlan Nov. 14, 2017, 10:12 p.m. UTC

From: Florian Fainelli <[e-mail]>

This commit adds a memory API suitable for ascertaining the sizes of
each of the N memory controllers in a Broadcom STB chip.  Its first
user will be the Broadcom STB PCIe root complex driver, which needs
to know these sizes to properly set up DMA mappings for inbound
regions.

We cannot use memblock here or anything like what Linux provides
because it collapses adjacent regions within a larger block, and here
we actually need per-memory controller addresses and sizes, which is
why we resort to manual DT parsing.

Signed-off-by: Jim Quinlan <[e-mail]>
---
 drivers/soc/bcm/brcmstb/Makefile |   2 +-
 drivers/soc/bcm/brcmstb/memory.c | 172 +++++++++++++++++++++++++++++++++++++++
 include/soc/brcmstb/memory_api.h |  25 ++++++
 3 files changed, 198 insertions(+), 1 deletion(-)
 create mode 100644 drivers/soc/bcm/brcmstb/memory.c
 create mode 100644 include/soc/brcmstb/memory_api.h

Comments

Bjorn Helgaas Dec. 5, 2017, 8:59 p.m. UTC | #1

On Tue, Nov 14, 2017 at 05:12:05PM -0500, Jim Quinlan wrote:
> From: Florian Fainelli <[e-mail]>
> 
> This commit adds a memory API suitable for ascertaining the sizes of
> each of the N memory controllers in a Broadcom STB chip.  Its first
> user will be the Broadcom STB PCIe root complex driver, which needs
> to know these sizes to properly set up DMA mappings for inbound
> regions.
> 
> We cannot use memblock here or anything like what Linux provides
> because it collapses adjacent regions within a larger block, and here
> we actually need per-memory controller addresses and sizes, which is
> why we resort to manual DT parsing.
> 
> Signed-off-by: Jim Quinlan <[e-mail]>
> ---
>  drivers/soc/bcm/brcmstb/Makefile |   2 +-
>  drivers/soc/bcm/brcmstb/memory.c | 172 +++++++++++++++++++++++++++++++++++++++
>  include/soc/brcmstb/memory_api.h |  25 ++++++
>  3 files changed, 198 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/soc/bcm/brcmstb/memory.c
>  create mode 100644 include/soc/brcmstb/memory_api.h
> 
> diff --git a/drivers/soc/bcm/brcmstb/Makefile b/drivers/soc/bcm/brcmstb/Makefile
> index 9120b27..4cea7b6 100644
> --- a/drivers/soc/bcm/brcmstb/Makefile
> +++ b/drivers/soc/bcm/brcmstb/Makefile
> @@ -1 +1 @@
> -obj-y				+= common.o biuctrl.o
> +obj-y				+= common.o biuctrl.o memory.o
> diff --git a/drivers/soc/bcm/brcmstb/memory.c b/drivers/soc/bcm/brcmstb/memory.c
> new file mode 100644
> index 0000000..eb647ad9
> --- /dev/null
> +++ b/drivers/soc/bcm/brcmstb/memory.c

I sort of assume based on [1] that every new file should have an SPDX
identifier ("The Linux kernel requires the precise SPDX identifier in
all source files") and that the actual text of the GPL can be omitted.

Only a few files in drivers/pci currently have an SPDX identifier.  I
don't know if that's oversight or work-in-progress or what.

[1] https://lkml.kernel.org/r/[e-mail]

> @@ -0,0 +1,172 @@
> +/*
> + * Copyright © 2015-2017 Broadcom
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * A copy of the GPL is available at
> + * http://www.broadcom.com/licenses/GPLv2.php or from the Free Software
> + * Foundation at https://www.gnu.org/licenses/ .

Florian Fainelli Dec. 8, 2017, 11:28 p.m. UTC | #2

On 12/05/2017 12:59 PM, Bjorn Helgaas wrote:
> On Tue, Nov 14, 2017 at 05:12:05PM -0500, Jim Quinlan wrote:
>> From: Florian Fainelli <[e-mail]>
>>
>> This commit adds a memory API suitable for ascertaining the sizes of
>> each of the N memory controllers in a Broadcom STB chip.  Its first
>> user will be the Broadcom STB PCIe root complex driver, which needs
>> to know these sizes to properly set up DMA mappings for inbound
>> regions.
>>
>> We cannot use memblock here or anything like what Linux provides
>> because it collapses adjacent regions within a larger block, and here
>> we actually need per-memory controller addresses and sizes, which is
>> why we resort to manual DT parsing.
>>
>> Signed-off-by: Jim Quinlan <[e-mail]>
>> ---
>>  drivers/soc/bcm/brcmstb/Makefile |   2 +-
>>  drivers/soc/bcm/brcmstb/memory.c | 172 +++++++++++++++++++++++++++++++++++++++
>>  include/soc/brcmstb/memory_api.h |  25 ++++++
>>  3 files changed, 198 insertions(+), 1 deletion(-)
>>  create mode 100644 drivers/soc/bcm/brcmstb/memory.c
>>  create mode 100644 include/soc/brcmstb/memory_api.h
>>
>> diff --git a/drivers/soc/bcm/brcmstb/Makefile b/drivers/soc/bcm/brcmstb/Makefile
>> index 9120b27..4cea7b6 100644
>> --- a/drivers/soc/bcm/brcmstb/Makefile
>> +++ b/drivers/soc/bcm/brcmstb/Makefile
>> @@ -1 +1 @@
>> -obj-y				+= common.o biuctrl.o
>> +obj-y				+= common.o biuctrl.o memory.o
>> diff --git a/drivers/soc/bcm/brcmstb/memory.c b/drivers/soc/bcm/brcmstb/memory.c
>> new file mode 100644
>> index 0000000..eb647ad9
>> --- /dev/null
>> +++ b/drivers/soc/bcm/brcmstb/memory.c
> 
> I sort of assume based on [1] that every new file should have an SPDX
> identifier ("The Linux kernel requires the precise SPDX identifier in
> all source files") and that the actual text of the GPL can be omitted.
> 
> Only a few files in drivers/pci currently have an SPDX identifier.  I
> don't know if that's oversight or work-in-progress or what.
> 
> [1] https://lkml.kernel.org/r/[e-mail]

This was submitted before SPDX was consistently enforced tree wide, so
yes we should fix this.

Any other comment besides that?

Jim Quinlan Dec. 12, 2017, 8:53 p.m. UTC | #3

On Tue, Dec 5, 2017 at 3:59 PM, Bjorn Helgaas <[e-mail]> wrote:
> On Tue, Nov 14, 2017 at 05:12:05PM -0500, Jim Quinlan wrote:
>> From: Florian Fainelli <[e-mail]>
>>
>> This commit adds a memory API suitable for ascertaining the sizes of
>> each of the N memory controllers in a Broadcom STB chip.  Its first
>> user will be the Broadcom STB PCIe root complex driver, which needs
>> to know these sizes to properly set up DMA mappings for inbound
>> regions.
>>
>> We cannot use memblock here or anything like what Linux provides
>> because it collapses adjacent regions within a larger block, and here
>> we actually need per-memory controller addresses and sizes, which is
>> why we resort to manual DT parsing.
>>
>> Signed-off-by: Jim Quinlan <[e-mail]>
>> ---
>>  drivers/soc/bcm/brcmstb/Makefile |   2 +-
>>  drivers/soc/bcm/brcmstb/memory.c | 172 +++++++++++++++++++++++++++++++++++++++
>>  include/soc/brcmstb/memory_api.h |  25 ++++++
>>  3 files changed, 198 insertions(+), 1 deletion(-)
>>  create mode 100644 drivers/soc/bcm/brcmstb/memory.c
>>  create mode 100644 include/soc/brcmstb/memory_api.h
>>
>> diff --git a/drivers/soc/bcm/brcmstb/Makefile b/drivers/soc/bcm/brcmstb/Makefile
>> index 9120b27..4cea7b6 100644
>> --- a/drivers/soc/bcm/brcmstb/Makefile
>> +++ b/drivers/soc/bcm/brcmstb/Makefile
>> @@ -1 +1 @@
>> -obj-y                                += common.o biuctrl.o
>> +obj-y                                += common.o biuctrl.o memory.o
>> diff --git a/drivers/soc/bcm/brcmstb/memory.c b/drivers/soc/bcm/brcmstb/memory.c
>> new file mode 100644
>> index 0000000..eb647ad9
>> --- /dev/null
>> +++ b/drivers/soc/bcm/brcmstb/memory.c
>
> I sort of assume based on [1] that every new file should have an SPDX
> identifier ("The Linux kernel requires the precise SPDX identifier in
> all source files") and that the actual text of the GPL can be omitted.
>
> Only a few files in drivers/pci currently have an SPDX identifier.  I
> don't know if that's oversight or work-in-progress or what.
>
> [1] https://lkml.kernel.org/r/[e-mail]
>

Bjorn, Did you get a chance to review the other commits of this
submission (V3)?  I would like any additional feedback before I send
out a V4 with SPDX fixes.  Thanks, JimQ

>> @@ -0,0 +1,172 @@
>> +/*
>> + * Copyright © 2015-2017 Broadcom
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + *
>> + * A copy of the GPL is available at
>> + * http://www.broadcom.com/licenses/GPLv2.php or from the Free Software
>> + * Foundation at https://www.gnu.org/licenses/ .

Bjorn Helgaas Dec. 12, 2017, 9:14 p.m. UTC | #4

[+cc Lorenzo]

On Tue, Dec 12, 2017 at 03:53:28PM -0500, Jim Quinlan wrote:
> On Tue, Dec 5, 2017 at 3:59 PM, Bjorn Helgaas <[e-mail]> wrote:
> > On Tue, Nov 14, 2017 at 05:12:05PM -0500, Jim Quinlan wrote:
> >> From: Florian Fainelli <[e-mail]>
> >>
> >> This commit adds a memory API suitable for ascertaining the sizes of
> >> each of the N memory controllers in a Broadcom STB chip.  Its first
> >> user will be the Broadcom STB PCIe root complex driver, which needs
> >> to know these sizes to properly set up DMA mappings for inbound
> >> regions.
> >>
> >> We cannot use memblock here or anything like what Linux provides
> >> because it collapses adjacent regions within a larger block, and here
> >> we actually need per-memory controller addresses and sizes, which is
> >> why we resort to manual DT parsing.
> >>
> >> Signed-off-by: Jim Quinlan <[e-mail]>
> >> ---
> >>  drivers/soc/bcm/brcmstb/Makefile |   2 +-
> >>  drivers/soc/bcm/brcmstb/memory.c | 172 +++++++++++++++++++++++++++++++++++++++
> >>  include/soc/brcmstb/memory_api.h |  25 ++++++
> >>  3 files changed, 198 insertions(+), 1 deletion(-)
> >>  create mode 100644 drivers/soc/bcm/brcmstb/memory.c
> >>  create mode 100644 include/soc/brcmstb/memory_api.h
> >>
> >> diff --git a/drivers/soc/bcm/brcmstb/Makefile b/drivers/soc/bcm/brcmstb/Makefile
> >> index 9120b27..4cea7b6 100644
> >> --- a/drivers/soc/bcm/brcmstb/Makefile
> >> +++ b/drivers/soc/bcm/brcmstb/Makefile
> >> @@ -1 +1 @@
> >> -obj-y                                += common.o biuctrl.o
> >> +obj-y                                += common.o biuctrl.o memory.o
> >> diff --git a/drivers/soc/bcm/brcmstb/memory.c b/drivers/soc/bcm/brcmstb/memory.c
> >> new file mode 100644
> >> index 0000000..eb647ad9
> >> --- /dev/null
> >> +++ b/drivers/soc/bcm/brcmstb/memory.c
> >
> > I sort of assume based on [1] that every new file should have an SPDX
> > identifier ("The Linux kernel requires the precise SPDX identifier in
> > all source files") and that the actual text of the GPL can be omitted.
> >
> > Only a few files in drivers/pci currently have an SPDX identifier.  I
> > don't know if that's oversight or work-in-progress or what.
> >
> > [1] https://lkml.kernel.org/r/[e-mail]
> >
> 
> Bjorn, Did you get a chance to review the other commits of this
> submission (V3)?  I would like any additional feedback before I send
> out a V4 with SPDX fixes.  Thanks, JimQ

Lorenzo is taking over drivers/pci/host/* and he'll no doubt have some
comments when he gets to this.  I'll point out a few quick formatting
things in the meantime.

> >> @@ -0,0 +1,172 @@
> >> +/*
> >> + * Copyright © 2015-2017 Broadcom
> >> + *
> >> + * This program is free software; you can redistribute it and/or modify
> >> + * it under the terms of the GNU General Public License version 2 as
> >> + * published by the Free Software Foundation.
> >> + *
> >> + * This program is distributed in the hope that it will be useful,
> >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> >> + * GNU General Public License for more details.
> >> + *
> >> + * A copy of the GPL is available at
> >> + * http://www.broadcom.com/licenses/GPLv2.php or from the Free Software
> >> + * Foundation at https://www.gnu.org/licenses/ .

Lorenzo Pieralisi Dec. 15, 2017, 5:14 p.m. UTC | #5

On Tue, Dec 12, 2017 at 03:14:04PM -0600, Bjorn Helgaas wrote:
> [+cc Lorenzo]
> 
> On Tue, Dec 12, 2017 at 03:53:28PM -0500, Jim Quinlan wrote:
> > On Tue, Dec 5, 2017 at 3:59 PM, Bjorn Helgaas <[e-mail]> wrote:
> > > On Tue, Nov 14, 2017 at 05:12:05PM -0500, Jim Quinlan wrote:
> > >> From: Florian Fainelli <[e-mail]>
> > >>
> > >> This commit adds a memory API suitable for ascertaining the sizes of
> > >> each of the N memory controllers in a Broadcom STB chip.  Its first
> > >> user will be the Broadcom STB PCIe root complex driver, which needs
> > >> to know these sizes to properly set up DMA mappings for inbound
> > >> regions.
> > >>
> > >> We cannot use memblock here or anything like what Linux provides
> > >> because it collapses adjacent regions within a larger block, and here
> > >> we actually need per-memory controller addresses and sizes, which is
> > >> why we resort to manual DT parsing.
> > >>
> > >> Signed-off-by: Jim Quinlan <[e-mail]>
> > >> ---
> > >>  drivers/soc/bcm/brcmstb/Makefile |   2 +-
> > >>  drivers/soc/bcm/brcmstb/memory.c | 172 +++++++++++++++++++++++++++++++++++++++
> > >>  include/soc/brcmstb/memory_api.h |  25 ++++++
> > >>  3 files changed, 198 insertions(+), 1 deletion(-)
> > >>  create mode 100644 drivers/soc/bcm/brcmstb/memory.c
> > >>  create mode 100644 include/soc/brcmstb/memory_api.h
> > >>
> > >> diff --git a/drivers/soc/bcm/brcmstb/Makefile b/drivers/soc/bcm/brcmstb/Makefile
> > >> index 9120b27..4cea7b6 100644
> > >> --- a/drivers/soc/bcm/brcmstb/Makefile
> > >> +++ b/drivers/soc/bcm/brcmstb/Makefile
> > >> @@ -1 +1 @@
> > >> -obj-y                                += common.o biuctrl.o
> > >> +obj-y                                += common.o biuctrl.o memory.o
> > >> diff --git a/drivers/soc/bcm/brcmstb/memory.c b/drivers/soc/bcm/brcmstb/memory.c
> > >> new file mode 100644
> > >> index 0000000..eb647ad9
> > >> --- /dev/null
> > >> +++ b/drivers/soc/bcm/brcmstb/memory.c
> > >
> > > I sort of assume based on [1] that every new file should have an SPDX
> > > identifier ("The Linux kernel requires the precise SPDX identifier in
> > > all source files") and that the actual text of the GPL can be omitted.
> > >
> > > Only a few files in drivers/pci currently have an SPDX identifier.  I
> > > don't know if that's oversight or work-in-progress or what.
> > >
> > > [1] https://lkml.kernel.org/r/[e-mail]
> > >
> > 
> > Bjorn, Did you get a chance to review the other commits of this
> > submission (V3)?  I would like any additional feedback before I send
> > out a V4 with SPDX fixes.  Thanks, JimQ
> 
> Lorenzo is taking over drivers/pci/host/* and he'll no doubt have some
> comments when he gets to this.  I'll point out a few quick formatting
> things in the meantime.

I need some time to review the code but overall I am quite worried about
patches 1 and 4 in particular, it is ok to have platform host bridge
drivers but we can't rewrite a DMA layer for a specific host bridge, I
really do not like that - it is just not manageable from a maintenance
perspective for the mainline kernel.

Lorenzo

Jim Quinlan Dec. 15, 2017, 7:50 p.m. UTC | #6

On Fri, Dec 15, 2017 at 12:14 PM, Lorenzo Pieralisi
<[e-mail]> wrote:
> On Tue, Dec 12, 2017 at 03:14:04PM -0600, Bjorn Helgaas wrote:
>> [+cc Lorenzo]
>>
>> On Tue, Dec 12, 2017 at 03:53:28PM -0500, Jim Quinlan wrote:
>> > On Tue, Dec 5, 2017 at 3:59 PM, Bjorn Helgaas <[e-mail]> wrote:
>> > > On Tue, Nov 14, 2017 at 05:12:05PM -0500, Jim Quinlan wrote:
>> > >> From: Florian Fainelli <[e-mail]>
>> > >>
>> > >> This commit adds a memory API suitable for ascertaining the sizes of
>> > >> each of the N memory controllers in a Broadcom STB chip.  Its first
>> > >> user will be the Broadcom STB PCIe root complex driver, which needs
>> > >> to know these sizes to properly set up DMA mappings for inbound
>> > >> regions.
>> > >>
>> > >> We cannot use memblock here or anything like what Linux provides
>> > >> because it collapses adjacent regions within a larger block, and here
>> > >> we actually need per-memory controller addresses and sizes, which is
>> > >> why we resort to manual DT parsing.
>> > >>
>> > >> Signed-off-by: Jim Quinlan <[e-mail]>
>> > >> ---
>> > >>  drivers/soc/bcm/brcmstb/Makefile |   2 +-
>> > >>  drivers/soc/bcm/brcmstb/memory.c | 172 +++++++++++++++++++++++++++++++++++++++
>> > >>  include/soc/brcmstb/memory_api.h |  25 ++++++
>> > >>  3 files changed, 198 insertions(+), 1 deletion(-)
>> > >>  create mode 100644 drivers/soc/bcm/brcmstb/memory.c
>> > >>  create mode 100644 include/soc/brcmstb/memory_api.h
>> > >>
>> > >> diff --git a/drivers/soc/bcm/brcmstb/Makefile b/drivers/soc/bcm/brcmstb/Makefile
>> > >> index 9120b27..4cea7b6 100644
>> > >> --- a/drivers/soc/bcm/brcmstb/Makefile
>> > >> +++ b/drivers/soc/bcm/brcmstb/Makefile
>> > >> @@ -1 +1 @@
>> > >> -obj-y                                += common.o biuctrl.o
>> > >> +obj-y                                += common.o biuctrl.o memory.o
>> > >> diff --git a/drivers/soc/bcm/brcmstb/memory.c b/drivers/soc/bcm/brcmstb/memory.c
>> > >> new file mode 100644
>> > >> index 0000000..eb647ad9
>> > >> --- /dev/null
>> > >> +++ b/drivers/soc/bcm/brcmstb/memory.c
>> > >
>> > > I sort of assume based on [1] that every new file should have an SPDX
>> > > identifier ("The Linux kernel requires the precise SPDX identifier in
>> > > all source files") and that the actual text of the GPL can be omitted.
>> > >
>> > > Only a few files in drivers/pci currently have an SPDX identifier.  I
>> > > don't know if that's oversight or work-in-progress or what.
>> > >
>> > > [1] https://lkml.kernel.org/r/[e-mail]
>> > >
>> >
>> > Bjorn, Did you get a chance to review the other commits of this
>> > submission (V3)?  I would like any additional feedback before I send
>> > out a V4 with SPDX fixes.  Thanks, JimQ
>>
>> Lorenzo is taking over drivers/pci/host/* and he'll no doubt have some
>> comments when he gets to this.  I'll point out a few quick formatting
>> things in the meantime.
>
> I need some time to review the code but overall I am quite worried about
> patches 1 and 4 in particular, it is ok to have platform host bridge
> drivers but we can't rewrite a DMA layer for a specific host bridge, I
> really do not like that - it is just not manageable from a maintenance
> perspective for the mainline kernel.
>
> Lorenzo
Hi Lorenzo,
First I note that the file drivers/pci/host/vmd.c appears to do the
same thing -- rewrite a layer over the DMA ops.  Secondly, there seems
to be no other way to accomplish what we need to do, especially that
will work with ARM, ARM64, and MIPs.  Someone raised the same point
you did and suggested I involve ARM/ARM64 maintainers, so I expanded
my "--to" list to include Russell.  I'm open to ideas.  I've asked the
HW PCIe folks to redesign the controller to accommodate an
identity-map for inbound memory, but it will be a while if that
happens, if ever. --Jim

Patch

diff --git a/drivers/soc/bcm/brcmstb/Makefile b/drivers/soc/bcm/brcmstb/Makefile
index 9120b27..4cea7b6 100644
--- a/drivers/soc/bcm/brcmstb/Makefile
+++ b/drivers/soc/bcm/brcmstb/Makefile
@@ -1 +1 @@ 
-obj-y				+= common.o biuctrl.o
+obj-y				+= common.o biuctrl.o memory.o
diff --git a/drivers/soc/bcm/brcmstb/memory.c b/drivers/soc/bcm/brcmstb/memory.c
new file mode 100644
index 0000000..eb647ad9
--- /dev/null
+++ b/drivers/soc/bcm/brcmstb/memory.c
@@ -0,0 +1,172 @@ 
+/*
+ * Copyright © 2015-2017 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * A copy of the GPL is available at
+ * http://www.broadcom.com/licenses/GPLv2.php or from the Free Software
+ * Foundation at https://www.gnu.org/licenses/ .
+ */
+
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/libfdt.h>
+#include <linux/of_address.h>
+#include <linux/of_fdt.h>
+#include <linux/sizes.h>
+#include <soc/brcmstb/memory_api.h>
+
+/* Macro to help extract property data */
+#define DT_PROP_DATA_TO_U32(b, offs) (fdt32_to_cpu(*(u32*)(b + offs)))
+
+/* Constants used when retrieving memc info */
+#define NUM_BUS_RANGES 10
+#define BUS_RANGE_ULIMIT_SHIFT 4
+#define BUS_RANGE_LLIMIT_SHIFT 4
+#define BUS_RANGE_PA_SHIFT 12
+
+enum {
+	BUSNUM_MCP0 = 0x4,
+	BUSNUM_MCP1 = 0x5,
+	BUSNUM_MCP2 = 0x6,
+};
+
+/*
+ * If the DT nodes are handy, determine which MEMC holds the specified
+ * physical address.
+ */
+#ifdef CONFIG_ARCH_BRCMSTB
+int __brcmstb_memory_phys_addr_to_memc(phys_addr_t pa, void __iomem *base)
+{
+	int memc = -1;
+	int i;
+
+	for (i = 0; i < NUM_BUS_RANGES; i++, base += 8) {
+		const u64 ulimit_raw = readl(base);
+		const u64 llimit_raw = readl(base + 4);
+		const u64 ulimit =
+			((ulimit_raw >> BUS_RANGE_ULIMIT_SHIFT)
+			 << BUS_RANGE_PA_SHIFT) | 0xfff;
+		const u64 llimit = (llimit_raw >> BUS_RANGE_LLIMIT_SHIFT)
+				   << BUS_RANGE_PA_SHIFT;
+		const u32 busnum = (u32)(ulimit_raw & 0xf);
+
+		if (pa >= llimit && pa <= ulimit) {
+			if (busnum >= BUSNUM_MCP0 && busnum <= BUSNUM_MCP2) {
+				memc = busnum - BUSNUM_MCP0;
+				break;
+			}
+		}
+	}
+
+	return memc;
+}
+
+int brcmstb_memory_phys_addr_to_memc(phys_addr_t pa)
+{
+	int memc = -1;
+	struct device_node *np;
+	void __iomem *cpubiuctrl;
+
+	np = of_find_compatible_node(NULL, NULL, "brcm,brcmstb-cpu-biu-ctrl");
+	if (!np)
+		return memc;
+
+	cpubiuctrl = of_iomap(np, 0);
+	if (!cpubiuctrl)
+		goto cleanup;
+
+	memc = __brcmstb_memory_phys_addr_to_memc(pa, cpubiuctrl);
+	iounmap(cpubiuctrl);
+
+cleanup:
+	of_node_put(np);
+
+	return memc;
+}
+
+#elif defined(CONFIG_MIPS)
+int brcmstb_memory_phys_addr_to_memc(phys_addr_t pa)
+{
+	/* The logic here is fairly simple and hardcoded: if pa <= 0x5000_0000,
+	 * then this is MEMC0, else MEMC1.
+	 *
+	 * For systems with 2GB on MEMC0, MEMC1 starts at 9000_0000, with 1GB
+	 * on MEMC0, MEMC1 starts at 6000_0000.
+	 */
+	if (pa >= 0x50000000ULL)
+		return 1;
+	else
+		return 0;
+}
+#endif
+
+u64 brcmstb_memory_memc_size(int memc)
+{
+	const void *fdt = initial_boot_params;
+	const int mem_offset = fdt_path_offset(fdt, "/memory");
+	int addr_cells = 1, size_cells = 1;
+	const struct fdt_property *prop;
+	int proplen, cellslen;
+	u64 memc_size = 0;
+	int i;
+
+	/* Get root size and address cells if specified */
+	prop = fdt_get_property(fdt, 0, "#size-cells", &proplen);
+	if (prop)
+		size_cells = DT_PROP_DATA_TO_U32(prop->data, 0);
+
+	prop = fdt_get_property(fdt, 0, "#address-cells", &proplen);
+	if (prop)
+		addr_cells = DT_PROP_DATA_TO_U32(prop->data, 0);
+
+	if (mem_offset < 0)
+		return -1;
+
+	prop = fdt_get_property(fdt, mem_offset, "reg", &proplen);
+	cellslen = (int)sizeof(u32) * (addr_cells + size_cells);
+	if ((proplen % cellslen) != 0)
+		return -1;
+
+	for (i = 0; i < proplen / cellslen; ++i) {
+		u64 addr = 0;
+		u64 size = 0;
+		int memc_idx;
+		int j;
+
+		for (j = 0; j < addr_cells; ++j) {
+			int offset = (cellslen * i) + (sizeof(u32) * j);
+
+			addr |= (u64)DT_PROP_DATA_TO_U32(prop->data, offset) <<
+				((addr_cells - j - 1) * 32);
+		}
+		for (j = 0; j < size_cells; ++j) {
+			int offset = (cellslen * i) +
+				(sizeof(u32) * (j + addr_cells));
+
+			size |= (u64)DT_PROP_DATA_TO_U32(prop->data, offset) <<
+				((size_cells - j - 1) * 32);
+		}
+
+		if ((phys_addr_t)addr != addr) {
+			pr_err("phys_addr_t is smaller than provided address 0x%llx!\n",
+			       addr);
+			return -1;
+		}
+
+		memc_idx = brcmstb_memory_phys_addr_to_memc((phys_addr_t)addr);
+		if (memc_idx == memc)
+			memc_size += size;
+	}
+
+	return memc_size;
+}
+EXPORT_SYMBOL_GPL(brcmstb_memory_memc_size);
+
diff --git a/include/soc/brcmstb/memory_api.h b/include/soc/brcmstb/memory_api.h
new file mode 100644
index 0000000..d922906
--- /dev/null
+++ b/include/soc/brcmstb/memory_api.h
@@ -0,0 +1,25 @@ 
+#ifndef __MEMORY_API_H
+#define __MEMORY_API_H
+
+/*
+ * Bus Interface Unit control register setup, must happen early during boot,
+ * before SMP is brought up, called by machine entry point.
+ */
+void brcmstb_biuctrl_init(void);
+
+#ifdef CONFIG_SOC_BRCMSTB
+int brcmstb_memory_phys_addr_to_memc(phys_addr_t pa);
+u64 brcmstb_memory_memc_size(int memc);
+#else
+static inline int brcmstb_memory_phys_addr_to_memc(phys_addr_t pa)
+{
+	return -EINVAL;
+}
+
+static inline u64 brcmstb_memory_memc_size(int memc)
+{
+	return -1;
+}
+#endif
+
+#endif /* __MEMORY_API_H */