[PATCH v2 0/3] ARM: brcmstb: Bus Interface Unit support

[PATCH v2 0/3] ARM: brcmstb: Bus Interface Unit support

[Florian Fainelli]

Hi all,

This patch series adds support for early boot time Bus Interface Unit control
register setup which is required to occur before SMP is brought-up, but needs
to remap registers, so init_irq() is chosen for that.

This builds on top of the 'soc/next' branch at github.com/Broadcom/stblinux

Major changes in v2:

- updated Device Tree documentation based on Rob's feedback
- added a better pr_fmt format for pr_* calls in biuctrl.c

Florian Fainelli (3):
  Documentation: bindings: brcmstb: Document write-pairing
  soc: brcmstb: Add Bus Interface Unit control setup
  ARM: brcmstb: Setup BIU control registers during boot

 .../devicetree/bindings/arm/bcm/brcm,brcmstb.txt   |  20 ++++
 arch/arm/mach-bcm/brcmstb.c                        |   9 ++
 drivers/soc/brcmstb/Makefile                       |   2 +-
 drivers/soc/brcmstb/biuctrl.c                      | 119 +++++++++++++++++++++
 include/linux/soc/brcmstb/brcmstb.h                |  10 ++
 5 files changed, 159 insertions(+), 1 deletion(-)
 create mode 100644 drivers/soc/brcmstb/biuctrl.c
 create mode 100644 include/linux/soc/brcmstb/brcmstb.h

-- 
2.1.0

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[PATCH v2 1/3] Documentation: bindings: brcmstb: Document write-pairing

[Florian Fainelli]

Document the hif-cpubiuctrl node a bit more, and add a documentation
entry for the optional "brcm,write-pairing" property.

Signed-off-by: Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
Changes in v2:

- added a description of what the BIU stands for and what write pairing is
- fixed the compatible string description

 .../devicetree/bindings/arm/bcm/brcm,brcmstb.txt     | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/bcm/brcm,brcmstb.txt b/Documentation/devicetree/bindings/arm/bcm/brcm,brcmstb.txt
index 430608ec09f0..8ac28eb4a5a1 100644
--- a/Documentation/devicetree/bindings/arm/bcm/brcm,brcmstb.txt
+++ b/Documentation/devicetree/bindings/arm/bcm/brcm,brcmstb.txt
@@ -20,6 +20,25 @@ system control is required:
     - compatible: "brcm,bcm<chip_id>-hif-cpubiuctrl", "syscon"
     - compatible: "brcm,bcm<chip_id>-hif-continuation", "syscon"
 
+hif-cpubiuctrl node
+-------------------
+SoCs with Broadcom Brahma15 ARM-based CPUs have a specific Bus Interface Unit
+(BIU) block which controls and interfaces the CPU complex to the different
+Memory Controller Ports (MCP), one per memory controller (MEMC). This BIU block
+offers a feature called Write Pairing which consists in collapsing two adjacent
+cache lines into a single (bursted) write transaction towards the memory
+controller (MEMC) to maximize write bandwidth.
+
+Required properties:
+
+    - compatible: must be "brcm,bcm7445-hif-cpubiuctrl", "syscon"
+
+Optional properties:
+
+    - brcm,write-pairing:
+	Boolean property, which when present indicates that the chip
+	supports write-pairing.
+
 example:
     rdb {
         #address-cells = <1>;
@@ -35,6 +54,7 @@ example:
         hif_cpubiuctrl: syscon@3e2400 {
             compatible = "brcm,bcm7445-hif-cpubiuctrl", "syscon";
             reg = <0x3e2400 0x5b4>;
+            brcm,write-pairing;
         };
 
         hif_continuation: syscon@452000 {
-- 
2.1.0

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Re: [PATCH v2 1/3] Documentation: bindings: brcmstb: Document write-pairing

[Gregory Fong]

On Tue, Sep 15, 2015 at 11:14 AM, Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> Document the hif-cpubiuctrl node a bit more, and add a documentation
> entry for the optional "brcm,write-pairing" property.
>
> Signed-off-by: Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Acked-by: Gregory Fong <gregory.0xf0-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
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Re: [PATCH v2 1/3] Documentation: bindings: brcmstb: Document write-pairing

[Florian Fainelli]

On 16/09/15 23:09, Gregory Fong wrote:
> On Tue, Sep 15, 2015 at 11:14 AM, Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> Document the hif-cpubiuctrl node a bit more, and add a documentation
>> entry for the optional "brcm,write-pairing" property.
>>
>> Signed-off-by: Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> 
> Acked-by: Gregory Fong <gregory.0xf0-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> 

Applied to devicetree/next, thanks!
-- 
Florian
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[PATCH v2 2/3] soc: brcmstb: Add Bus Interface Unit control setup

[Florian Fainelli]

Broadcom STB SoCs (brcmstb) require an early setup of their Bus
Interface Unit control register, this needs to happen before SMP is
brought up because it affects how the CPU complex will be interfaced to
the memory controller.

Add support code which properly initializes the BIU registers based on
whether "brcm,write-pairing" is present in Device Tree, and take care of
saving and restoring credit register settings during system-wide
suspend/resume operations.

Signed-off-by: Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
Changes in v2:

- add a pr_fmt prefix which is more descriptive

 drivers/soc/brcmstb/Makefile        |   2 +-
 drivers/soc/brcmstb/biuctrl.c       | 119 ++++++++++++++++++++++++++++++++++++
 include/linux/soc/brcmstb/brcmstb.h |  10 +++
 3 files changed, 130 insertions(+), 1 deletion(-)
 create mode 100644 drivers/soc/brcmstb/biuctrl.c
 create mode 100644 include/linux/soc/brcmstb/brcmstb.h

diff --git a/drivers/soc/brcmstb/Makefile b/drivers/soc/brcmstb/Makefile
index 677e3fa0d042..75df0e0c091d 100644
--- a/drivers/soc/brcmstb/Makefile
+++ b/drivers/soc/brcmstb/Makefile
@@ -1,3 +1,3 @@
 obj-$(CONFIG_BRCMSTB_PM)	+= pm/
 
-obj-y				+= common.o
+obj-y				+= common.o biuctrl.o
diff --git a/drivers/soc/brcmstb/biuctrl.c b/drivers/soc/brcmstb/biuctrl.c
new file mode 100644
index 000000000000..1d4deada1c4d
--- /dev/null
+++ b/drivers/soc/brcmstb/biuctrl.c
@@ -0,0 +1,119 @@
+/*
+ * Broadcom STB SoCs Bus Unit Interface controls
+ *
+ * Copyright (C) 2015, Broadcom Corporation
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt)	"brcmstb: " KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/syscore_ops.h>
+
+#define CPU_CREDIT_REG_OFFSET			0x184
+#define  CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK	0x70000000
+
+static void __iomem *cpubiuctrl_base;
+static bool mcp_wr_pairing_en;
+
+static int __init mcp_write_pairing_set(void)
+{
+	u32 creds = 0;
+
+	if (!cpubiuctrl_base)
+		return -1;
+
+	creds = readl_relaxed(cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
+	if (mcp_wr_pairing_en) {
+		pr_info("MCP: Enabling write pairing\n");
+		writel_relaxed(creds | CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK,
+			     cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
+	} else if (creds & CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK) {
+		pr_info("MCP: Disabling write pairing\n");
+		writel_relaxed(creds & ~CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK,
+				cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
+	} else {
+		pr_info("MCP: Write pairing already disabled\n");
+	}
+
+	return 0;
+}
+
+static int __init setup_hifcpubiuctrl_regs(void)
+{
+	struct device_node *np;
+	int ret = 0;
+
+	np = of_find_compatible_node(NULL, NULL, "brcm,brcmstb-cpu-biu-ctrl");
+	if (!np) {
+		pr_err("missing BIU control node\n");
+		return -ENODEV;
+	}
+
+	cpubiuctrl_base = of_iomap(np, 0);
+	if (!cpubiuctrl_base) {
+		pr_err("failed to remap BIU control base\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	mcp_wr_pairing_en = of_property_read_bool(np, "brcm,write-pairing");
+out:
+	of_node_put(np);
+	return ret;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static u32 cpu_credit_reg_dump;  /* for save/restore */
+
+static int brcmstb_cpu_credit_reg_suspend(void)
+{
+	if (cpubiuctrl_base)
+		cpu_credit_reg_dump =
+			readl_relaxed(cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
+	return 0;
+}
+
+static void brcmstb_cpu_credit_reg_resume(void)
+{
+	if (cpubiuctrl_base)
+		writel_relaxed(cpu_credit_reg_dump,
+				cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
+}
+
+static struct syscore_ops brcmstb_cpu_credit_syscore_ops = {
+	.suspend = brcmstb_cpu_credit_reg_suspend,
+	.resume = brcmstb_cpu_credit_reg_resume,
+};
+#endif
+
+
+int __init brcmstb_biuctrl_init(void)
+{
+	int ret = 0;
+
+	ret = setup_hifcpubiuctrl_regs();
+	if (ret)
+		return ret;
+
+	ret = mcp_write_pairing_set();
+	if (ret) {
+		pr_err("MCP: Unable to disable write pairing!\n");
+		return ret;
+	}
+
+#ifdef CONFIG_PM_SLEEP
+	register_syscore_ops(&brcmstb_cpu_credit_syscore_ops);
+#endif
+	return ret;
+}
diff --git a/include/linux/soc/brcmstb/brcmstb.h b/include/linux/soc/brcmstb/brcmstb.h
new file mode 100644
index 000000000000..7009f61ea24c
--- /dev/null
+++ b/include/linux/soc/brcmstb/brcmstb.h
@@ -0,0 +1,10 @@
+#ifndef __BRCMSTB_SOC_H
+#define __BRCMSTB_SOC_H
+
+/*
+ * Bus Interface Unit control register setup, must happen early during boot,
+ * before SMP is brought up, called by machine entry point.
+ */
+int brcmstb_biuctrl_init(void);
+
+#endif /* __BRCMSTB_SOC_H */
-- 
2.1.0

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Re: [PATCH v2 2/3] soc: brcmstb: Add Bus Interface Unit control setup

[Gregory Fong]

On Tue, Sep 15, 2015 at 11:14 AM, Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> Broadcom STB SoCs (brcmstb) require an early setup of their Bus
> Interface Unit control register, this needs to happen before SMP is
> brought up because it affects how the CPU complex will be interfaced to
> the memory controller.
>
> Add support code which properly initializes the BIU registers based on
> whether "brcm,write-pairing" is present in Device Tree, and take care of
> saving and restoring credit register settings during system-wide
> suspend/resume operations.
>
> Signed-off-by: Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
> Changes in v2:
>
> - add a pr_fmt prefix which is more descriptive
>
>  drivers/soc/brcmstb/Makefile        |   2 +-
>  drivers/soc/brcmstb/biuctrl.c       | 119 ++++++++++++++++++++++++++++++++++++
>  include/linux/soc/brcmstb/brcmstb.h |  10 +++
>  3 files changed, 130 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/soc/brcmstb/biuctrl.c
>  create mode 100644 include/linux/soc/brcmstb/brcmstb.h
>
> [...]
> diff --git a/drivers/soc/brcmstb/biuctrl.c b/drivers/soc/brcmstb/biuctrl.c
> new file mode 100644
> index 000000000000..1d4deada1c4d
> --- /dev/null
> +++ b/drivers/soc/brcmstb/biuctrl.c
> @@ -0,0 +1,119 @@
> [...]
> +int __init brcmstb_biuctrl_init(void)
> +{
> +       int ret = 0;
> +
> +       ret = setup_hifcpubiuctrl_regs();
> +       if (ret)
> +               return ret;
> +
> +       ret = mcp_write_pairing_set();
> +       if (ret) {
> +               pr_err("MCP: Unable to disable write pairing!\n");
> +               return ret;

The return value isn't used in patch 3.  Is there a point to returning
an error from this function in either of the above two locations,
considering that?

Looks good otherwise.

Acked-by: Gregory Fong <gregory.0xf0-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
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Re: [PATCH v2 2/3] soc: brcmstb: Add Bus Interface Unit control setup

[Florian Fainelli]

On 16/09/15 23:08, Gregory Fong wrote:
>> [...]
>> diff --git a/drivers/soc/brcmstb/biuctrl.c b/drivers/soc/brcmstb/biuctrl.c
>> new file mode 100644
>> index 000000000000..1d4deada1c4d
>> --- /dev/null
>> +++ b/drivers/soc/brcmstb/biuctrl.c
>> @@ -0,0 +1,119 @@
>> [...]
>> +int __init brcmstb_biuctrl_init(void)
>> +{
>> +       int ret = 0;
>> +
>> +       ret = setup_hifcpubiuctrl_regs();
>> +       if (ret)
>> +               return ret;
>> +
>> +       ret = mcp_write_pairing_set();
>> +       if (ret) {
>> +               pr_err("MCP: Unable to disable write pairing!\n");
>> +               return ret;
> 
> The return value isn't used in patch 3.  Is there a point to returning
> an error from this function in either of the above two locations,
> considering that?
> 
> Looks good otherwise.
> 
> Acked-by: Gregory Fong <gregory.0xf0-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Not really, how about this:

void __init brcmstb_biuctrl_init(void)
{
        int ret;

        setup_hifcpubiuctrl_regs();

        ret = mcp_write_pairing_set();
        if (ret) {
                pr_err("MCP: Unable to disable write pairing!\n");
                return;
        }

#ifdef CONFIG_PM_SLEEP
        register_syscore_ops(&brcmstb_cpu_credit_syscore_ops);
#endif
}

and updating the function prototype accordingly in the header file?
-- 
Florian
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Re: [PATCH v2 2/3] soc: brcmstb: Add Bus Interface Unit control setup

[Gregory Fong]

On Thu, Sep 17, 2015 at 10:42 AM, Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On 16/09/15 23:08, Gregory Fong wrote:
>>> [...]
>>> diff --git a/drivers/soc/brcmstb/biuctrl.c b/drivers/soc/brcmstb/biuctrl.c
>>> new file mode 100644
>>> index 000000000000..1d4deada1c4d
>>> --- /dev/null
>>> +++ b/drivers/soc/brcmstb/biuctrl.c
>>> @@ -0,0 +1,119 @@
>>> [...]
>>> +int __init brcmstb_biuctrl_init(void)
>>> +{
>>> +       int ret = 0;
>>> +
>>> +       ret = setup_hifcpubiuctrl_regs();
>>> +       if (ret)
>>> +               return ret;
>>> +
>>> +       ret = mcp_write_pairing_set();
>>> +       if (ret) {
>>> +               pr_err("MCP: Unable to disable write pairing!\n");
>>> +               return ret;
>>
>> The return value isn't used in patch 3.  Is there a point to returning
>> an error from this function in either of the above two locations,
>> considering that?
>>
>> Looks good otherwise.
>>
>> Acked-by: Gregory Fong <gregory.0xf0-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>
> Not really, how about this:
>
> void __init brcmstb_biuctrl_init(void)
> {
>         int ret;
>
>         setup_hifcpubiuctrl_regs();
>
>         ret = mcp_write_pairing_set();
>         if (ret) {
>                 pr_err("MCP: Unable to disable write pairing!\n");
>                 return;
>         }
>
> #ifdef CONFIG_PM_SLEEP
>         register_syscore_ops(&brcmstb_cpu_credit_syscore_ops);
> #endif
> }
>
> and updating the function prototype accordingly in the header file?

Sure, that works.

Thanks,
Gregory
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Re: [PATCH v2 2/3] soc: brcmstb: Add Bus Interface Unit control setup

[Florian Fainelli]

On 15/09/15 11:14, Florian Fainelli wrote:
> Broadcom STB SoCs (brcmstb) require an early setup of their Bus
> Interface Unit control register, this needs to happen before SMP is
> brought up because it affects how the CPU complex will be interfaced to
> the memory controller.
> 
> Add support code which properly initializes the BIU registers based on
> whether "brcm,write-pairing" is present in Device Tree, and take care of
> saving and restoring credit register settings during system-wide
> suspend/resume operations.
> 
> Signed-off-by: Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Applied to soc/next with Gregory's tag and the revised function
prototype returning void.
-- 
Florian
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[PATCH v2 3/3] ARM: brcmstb: Setup BIU control registers during boot

[Florian Fainelli]

Call brcmstb_biuctrl_init() in brcmstb's init_irq machine descriptor
callback since we need to setup the Bus Interface Unit before SMP in
particular, but we also need to be able to remap registers.

Signed-off-by: Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 arch/arm/mach-bcm/brcmstb.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm/mach-bcm/brcmstb.c b/arch/arm/mach-bcm/brcmstb.c
index 3a60f7ee3f0c..99a67cfb7c0d 100644
--- a/arch/arm/mach-bcm/brcmstb.c
+++ b/arch/arm/mach-bcm/brcmstb.c
@@ -12,11 +12,19 @@
  */
 
 #include <linux/init.h>
+#include <linux/irqchip.h>
 #include <linux/of_platform.h>
+#include <linux/soc/brcmstb/brcmstb.h>
 
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
 
+static void __init brcmstb_init_irq(void)
+{
+	irqchip_init();
+	brcmstb_biuctrl_init();
+}
+
 static const char *const brcmstb_match[] __initconst = {
 	"brcm,bcm7445",
 	"brcm,brcmstb",
@@ -25,4 +33,5 @@ static const char *const brcmstb_match[] __initconst = {
 
 DT_MACHINE_START(BRCMSTB, "Broadcom STB (Flattened Device Tree)")
 	.dt_compat	= brcmstb_match,
+	.init_irq	= brcmstb_init_irq,
 MACHINE_END
-- 
2.1.0

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Re: [PATCH v2 3/3] ARM: brcmstb: Setup BIU control registers during boot

[Gregory Fong]

On Tue, Sep 15, 2015 at 11:15 AM, Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> Call brcmstb_biuctrl_init() in brcmstb's init_irq machine descriptor
> callback since we need to setup the Bus Interface Unit before SMP in
> particular, but we also need to be able to remap registers.
>
> Signed-off-by: Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Acked-by: Gregory Fong <gregory.0xf0-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
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Re: [PATCH v2 3/3] ARM: brcmstb: Setup BIU control registers during boot

[Florian Fainelli]

On 15/09/15 11:15, Florian Fainelli wrote:
> Call brcmstb_biuctrl_init() in brcmstb's init_irq machine descriptor
> callback since we need to setup the Bus Interface Unit before SMP in
> particular, but we also need to be able to remap registers.
> 
> Signed-off-by: Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Applied to soc/next.
-- 
Florian
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