[PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver

[PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver

[Hiroshi DOYU]

Tegra AHB Bus conforms to the AMBA Specification (Rev 2.0) Advanced
High-performance Bus (AHB) architecture.

The AHB Arbiter controls AHB bus master arbitration. This effectively
forms a second level of arbitration for access to the memory
controller through the AHB Slave Memory device. The AHB pre-fetch
logic can be configured to enhance performance for devices doing
sequential access. Each AHB master is assigned to either the high or
low priority bin. Both Tegra20/30 have this AHB bus.

Some of configuration param could be passed from DT too.

Signed-off-by: Hiroshi DOYU <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Cc: Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>
Cc: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
---
 arch/arm/mach-tegra/Kconfig |    8 ++
 drivers/Makefile            |    2 +-
 drivers/amba/Makefile       |    4 +-
 drivers/amba/tegra-ahb.c    |  272 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 283 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-tegra/Kconfig b/arch/arm/mach-tegra/Kconfig
index 204d3d4..6a113a9 100644
--- a/arch/arm/mach-tegra/Kconfig
+++ b/arch/arm/mach-tegra/Kconfig
@@ -50,6 +50,14 @@ config TEGRA_PCI
 	depends on ARCH_TEGRA_2x_SOC
 	select PCI
 
+config TEGRA_AHB
+	bool "Enable AHB driver for NVIDIA Tegra SoCs"
+	default y
+	help
+	  Adds AHB configuration functionality for NVIDIA Tegra SoCs,
+	  which controls AHB bus master arbitration and some
+	  perfomance parameters(priority, prefech size).
+
 comment "Tegra board type"
 
 config MACH_HARMONY
diff --git a/drivers/Makefile b/drivers/Makefile
index 5870322..d97e2e2 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -18,7 +18,7 @@ obj-$(CONFIG_SFI)		+= sfi/
 # PnP must come after ACPI since it will eventually need to check if acpi
 # was used and do nothing if so
 obj-$(CONFIG_PNP)		+= pnp/
-obj-$(CONFIG_ARM_AMBA)		+= amba/
+obj-$(CONFIG_ARM)		+= amba/
 # Many drivers will want to use DMA so this has to be made available
 # really early.
 obj-$(CONFIG_DMA_ENGINE)	+= dma/
diff --git a/drivers/amba/Makefile b/drivers/amba/Makefile
index 40fe740..66e81c2 100644
--- a/drivers/amba/Makefile
+++ b/drivers/amba/Makefile
@@ -1,2 +1,2 @@
-obj-y		+= bus.o
-
+obj-$(CONFIG_ARM_AMBA)		+= bus.o
+obj-$(CONFIG_TEGRA_AHB)		+= tegra-ahb.o
diff --git a/drivers/amba/tegra-ahb.c b/drivers/amba/tegra-ahb.c
new file mode 100644
index 0000000..03933f3
--- /dev/null
+++ b/drivers/amba/tegra-ahb.c
@@ -0,0 +1,272 @@
+/*
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Author:
+ *	Jay Cheng <jacheng-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
+ *	James Wylder <james.wylder-3WKxDLwmzFNWk0Htik3J/w@public.gmane.org>
+ *	Benoit Goby <benoit-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
+ *	Colin Cross <ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
+ *	Hiroshi DOYU <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#define DRV_NAME "tegra-ahb"
+
+#define AHB_ARBITRATION_DISABLE		0x00
+#define AHB_ARBITRATION_PRIORITY_CTRL	0x04
+#define   AHB_PRIORITY_WEIGHT(x)	(((x) & 0x7) << 29)
+#define   PRIORITY_SELECT_USB BIT(6)
+#define   PRIORITY_SELECT_USB2 BIT(18)
+#define   PRIORITY_SELECT_USB3 BIT(17)
+
+#define AHB_GIZMO_AHB_MEM		0x0c
+#define   ENB_FAST_REARBITRATE BIT(2)
+#define   DONT_SPLIT_AHB_WR     BIT(7)
+
+#define AHB_GIZMO_APB_DMA		0x10
+#define AHB_GIZMO_IDE			0x18
+#define AHB_GIZMO_USB			0x1c
+#define AHB_GIZMO_AHB_XBAR_BRIDGE	0x20
+#define AHB_GIZMO_CPU_AHB_BRIDGE	0x24
+#define AHB_GIZMO_COP_AHB_BRIDGE	0x28
+#define AHB_GIZMO_XBAR_APB_CTLR		0x2c
+#define AHB_GIZMO_VCP_AHB_BRIDGE	0x30
+#define AHB_GIZMO_NAND			0x3c
+#define AHB_GIZMO_SDMMC4		0x44
+#define AHB_GIZMO_XIO			0x48
+#define AHB_GIZMO_BSEV			0x60
+#define AHB_GIZMO_BSEA			0x70
+#define AHB_GIZMO_NOR			0x74
+#define AHB_GIZMO_USB2			0x78
+#define AHB_GIZMO_USB3			0x7c
+#define   IMMEDIATE	BIT(18)
+
+#define AHB_GIZMO_SDMMC1		0x80
+#define AHB_GIZMO_SDMMC2		0x84
+#define AHB_GIZMO_SDMMC3		0x88
+#define AHB_MEM_PREFETCH_CFG_X		0xd8
+#define AHB_ARBITRATION_XBAR_CTRL	0xdc
+#define AHB_MEM_PREFETCH_CFG3		0xe0
+#define AHB_MEM_PREFETCH_CFG4		0xe4
+#define AHB_MEM_PREFETCH_CFG1		0xec
+#define AHB_MEM_PREFETCH_CFG2		0xf0
+#define   PREFETCH_ENB	BIT(31)
+#define   MST_ID(x)	(((x) & 0x1f) << 26)
+#define   AHBDMA_MST_ID	MST_ID(5)
+#define   USB_MST_ID	MST_ID(6)
+#define   USB2_MST_ID	MST_ID(18)
+#define   USB3_MST_ID	MST_ID(17)
+#define   ADDR_BNDRY(x)	(((x) & 0xf) << 21)
+#define   INACTIVITY_TIMEOUT(x)	(((x) & 0xffff) << 0)
+
+#define AHB_ARBITRATION_AHB_MEM_WRQUE_MST_ID	0xf8
+
+static u32 tegra_ahb_gizmo[] = {
+	AHB_ARBITRATION_DISABLE,
+	AHB_ARBITRATION_PRIORITY_CTRL,
+	AHB_GIZMO_AHB_MEM,
+	AHB_GIZMO_APB_DMA,
+	AHB_GIZMO_IDE,
+	AHB_GIZMO_USB,
+	AHB_GIZMO_AHB_XBAR_BRIDGE,
+	AHB_GIZMO_CPU_AHB_BRIDGE,
+	AHB_GIZMO_COP_AHB_BRIDGE,
+	AHB_GIZMO_XBAR_APB_CTLR,
+	AHB_GIZMO_VCP_AHB_BRIDGE,
+	AHB_GIZMO_NAND,
+	AHB_GIZMO_SDMMC4,
+	AHB_GIZMO_XIO,
+	AHB_GIZMO_BSEV,
+	AHB_GIZMO_BSEA,
+	AHB_GIZMO_NOR,
+	AHB_GIZMO_USB2,
+	AHB_GIZMO_USB3,
+	AHB_GIZMO_SDMMC1,
+	AHB_GIZMO_SDMMC2,
+	AHB_GIZMO_SDMMC3,
+	AHB_MEM_PREFETCH_CFG_X,
+	AHB_ARBITRATION_XBAR_CTRL,
+	AHB_MEM_PREFETCH_CFG3,
+	AHB_MEM_PREFETCH_CFG4,
+	AHB_MEM_PREFETCH_CFG1,
+	AHB_MEM_PREFETCH_CFG2,
+	AHB_ARBITRATION_AHB_MEM_WRQUE_MST_ID,
+};
+
+struct tegra_ahb {
+	void __iomem	*regs;
+	struct device	*dev;
+	u32		ctx[0];
+};
+
+static inline u32 gizmo_readl(struct tegra_ahb *ahb, u32 offset)
+{
+	return readl(ahb->regs + offset);
+}
+
+static inline void gizmo_writel(struct tegra_ahb *ahb, u32 value, u32 offset)
+{
+	writel(value, ahb->regs + offset);
+}
+
+static int tegra_ahb_suspend(struct device *dev)
+{
+	int i;
+	struct tegra_ahb *ahb = dev_get_drvdata(dev);
+
+	for (i = 0; i < ARRAY_SIZE(tegra_ahb_gizmo); i++)
+		ahb->ctx[i] = gizmo_readl(ahb, tegra_ahb_gizmo[i]);
+	return 0;
+}
+
+static int tegra_ahb_resume(struct device *dev)
+{
+	int i;
+	struct tegra_ahb *ahb = dev_get_drvdata(dev);
+
+	for (i = 0; i < ARRAY_SIZE(tegra_ahb_gizmo); i++)
+		gizmo_writel(ahb, ahb->ctx[i], tegra_ahb_gizmo[i]);
+	return 0;
+}
+
+static UNIVERSAL_DEV_PM_OPS(tegra_ahb_pm,
+			    tegra_ahb_suspend,
+			    tegra_ahb_resume, NULL);
+
+static void tegra_ahb_gizmo_init(struct tegra_ahb *ahb)
+{
+	u32 val;
+
+	val = gizmo_readl(ahb, AHB_GIZMO_AHB_MEM);
+	val |= ENB_FAST_REARBITRATE | IMMEDIATE | DONT_SPLIT_AHB_WR;
+	gizmo_writel(ahb, val, AHB_GIZMO_AHB_MEM);
+
+	val = gizmo_readl(ahb, AHB_GIZMO_USB);
+	val |= IMMEDIATE;
+	gizmo_writel(ahb, val, AHB_GIZMO_USB);
+
+	val = gizmo_readl(ahb, AHB_GIZMO_USB2);
+	val |= IMMEDIATE;
+	gizmo_writel(ahb, val, AHB_GIZMO_USB2);
+
+	val = gizmo_readl(ahb, AHB_GIZMO_USB3);
+	val |= IMMEDIATE;
+	gizmo_writel(ahb, val, AHB_GIZMO_USB3);
+
+	val = gizmo_readl(ahb, AHB_ARBITRATION_PRIORITY_CTRL);
+	val |= PRIORITY_SELECT_USB |
+		PRIORITY_SELECT_USB2 |
+		PRIORITY_SELECT_USB3 |
+		AHB_PRIORITY_WEIGHT(7);
+	gizmo_writel(ahb, val, AHB_ARBITRATION_PRIORITY_CTRL);
+
+	val = gizmo_readl(ahb, AHB_MEM_PREFETCH_CFG1);
+	val &= ~MST_ID(~0);
+	val |= PREFETCH_ENB |
+		AHBDMA_MST_ID |
+		ADDR_BNDRY(0xc) |
+		INACTIVITY_TIMEOUT(0x1000);
+	gizmo_writel(ahb, val, AHB_MEM_PREFETCH_CFG1);
+
+	val = gizmo_readl(ahb, AHB_MEM_PREFETCH_CFG2);
+	val &= ~MST_ID(~0);
+	val |= PREFETCH_ENB |
+		USB_MST_ID |
+		ADDR_BNDRY(0xc) |
+		INACTIVITY_TIMEOUT(0x1000);
+	gizmo_writel(ahb, val, AHB_MEM_PREFETCH_CFG2);
+
+	val = gizmo_readl(ahb, AHB_MEM_PREFETCH_CFG3);
+	val &= ~MST_ID(~0);
+	val |= PREFETCH_ENB |
+		USB3_MST_ID |
+		ADDR_BNDRY(0xc) |
+		INACTIVITY_TIMEOUT(0x1000);
+	gizmo_writel(ahb, val, AHB_MEM_PREFETCH_CFG3);
+
+	val = gizmo_readl(ahb, AHB_MEM_PREFETCH_CFG4);
+	val &= ~MST_ID(~0);
+	val |= PREFETCH_ENB |
+		USB2_MST_ID |
+		ADDR_BNDRY(0xc) |
+		INACTIVITY_TIMEOUT(0x1000);
+	gizmo_writel(ahb, val, AHB_MEM_PREFETCH_CFG4);
+}
+
+static int __devinit tegra_ahb_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct tegra_ahb *ahb;
+	size_t bytes;
+
+	bytes = sizeof(*ahb) + sizeof(u32) * ARRAY_SIZE(tegra_ahb_gizmo);
+	ahb = devm_kzalloc(&pdev->dev, bytes, GFP_KERNEL);
+	if (!ahb)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+	ahb->regs = devm_request_and_ioremap(&pdev->dev, res);
+	if (!ahb->regs)
+		return -EBUSY;
+
+	ahb->dev = &pdev->dev;
+	platform_set_drvdata(pdev, ahb);
+	tegra_ahb_gizmo_init(ahb);
+	return 0;
+}
+
+static int __devexit tegra_ahb_remove(struct platform_device *pdev)
+{
+	return 0;
+}
+
+static const struct of_device_id tegra_ahb_of_match[] __devinitconst = {
+	{ .compatible = "nvidia,tegra30-ahb", },
+	{ .compatible = "nvidia,tegra20-ahb", },
+	{},
+};
+
+static struct platform_driver tegra_ahb_driver = {
+	.probe = tegra_ahb_probe,
+	.remove = __devexit_p(tegra_ahb_remove),
+	.driver = {
+		.name = DRV_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = tegra_ahb_of_match,
+		.pm = &tegra_ahb_pm,
+	},
+};
+
+static int __init tegra_ahb_module_init(void)
+{
+	return platform_driver_register(&tegra_ahb_driver);
+}
+postcore_initcall(tegra_ahb_module_init);
+
+static void __exit tegra_ahb_module_exit(void)
+{
+	platform_driver_unregister(&tegra_ahb_driver);
+}
+module_exit(tegra_ahb_module_exit);
+
+MODULE_AUTHOR("Hiroshi DOYU <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>");
+MODULE_DESCRIPTION("Tegra AHB driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRV_NAME);
-- 
1.7.5.4

[PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Hiroshi DOYU]

Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
ready.

Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
Cc: Felipe Balbi <balbi@ti.com>
---
 arch/arm/mach-tegra/include/mach/tegra-ahb.h |   19 +++++++++++++++
 drivers/amba/tegra-ahb.c                     |   32 ++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-tegra/include/mach/tegra-ahb.h b/arch/arm/mach-tegra/include/mach/tegra-ahb.h
new file mode 100644
index 0000000..e0f8c84
--- /dev/null
+++ b/arch/arm/mach-tegra/include/mach/tegra-ahb.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#ifndef __MACH_TEGRA_AHB_H__
+#define __MACH_TEGRA_AHB_H__
+
+extern int tegra_ahb_enable_smmu(struct device_node *ahb);
+
+#endif	/* __MACH_TEGRA_AHB_H__ */
diff --git a/drivers/amba/tegra-ahb.c b/drivers/amba/tegra-ahb.c
index 03933f3..ec4e22f 100644
--- a/drivers/amba/tegra-ahb.c
+++ b/drivers/amba/tegra-ahb.c
@@ -76,6 +76,10 @@
 
 #define AHB_ARBITRATION_AHB_MEM_WRQUE_MST_ID	0xf8
 
+#define AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE BIT(17)
+
+static struct platform_driver tegra_ahb_driver;
+
 static u32 tegra_ahb_gizmo[] = {
 	AHB_ARBITRATION_DISABLE,
 	AHB_ARBITRATION_PRIORITY_CTRL,
@@ -124,6 +128,34 @@ static inline void gizmo_writel(struct tegra_ahb *ahb, u32 value, u32 offset)
 	writel(value, ahb->regs + offset);
 }
 
+#ifdef CONFIG_ARCH_TEGRA_3x_SOC
+static int tegra_ahb_match_by_smmu(struct device *dev, void *data)
+{
+	struct tegra_ahb *ahb = dev_get_drvdata(dev);
+	struct device_node *dn = data;
+
+	return (ahb->dev->of_node == dn) ? 1 : 0;
+}
+
+int tegra_ahb_enable_smmu(struct device_node *dn)
+{
+	struct device *dev;
+	u32 val;
+	struct tegra_ahb *ahb;
+
+	dev = driver_find_device(&tegra_ahb_driver.driver, NULL, dn,
+				 tegra_ahb_match_by_smmu);
+	if (!dev)
+		return -EPROBE_DEFER;
+	ahb = dev_get_drvdata(dev);
+	val = gizmo_readl(ahb, AHB_ARBITRATION_XBAR_CTRL);
+	val |= AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE;
+	gizmo_writel(ahb, val, AHB_ARBITRATION_XBAR_CTRL);
+	return 0;
+}
+EXPORT_SYMBOL(tegra_ahb_enable_smmu);
+#endif
+
 static int tegra_ahb_suspend(struct device *dev)
 {
 	int i;
-- 
1.7.5.4

Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Stephen Warren]

On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
> Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> ready.
> 
> Signed-off-by: Hiroshi DOYU <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> Cc: Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>

Acked-by: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>

[PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB

[Hiroshi DOYU]

Use "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
ready, instead of directly aceessing AHB registers.

Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
---
 drivers/iommu/tegra-smmu.c |   60 +++++++++++++++++--------------------------
 1 files changed, 24 insertions(+), 36 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index ecd6790..c70e4e7 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -30,12 +30,14 @@
 #include <linux/sched.h>
 #include <linux/iommu.h>
 #include <linux/io.h>
+#include <linux/of.h>
 
 #include <asm/page.h>
 #include <asm/cacheflush.h>
 
 #include <mach/iomap.h>
 #include <mach/smmu.h>
+#include <mach/tegra-ahb.h>
 
 /* bitmap of the page sizes currently supported */
 #define SMMU_IOMMU_PGSIZES	(SZ_4K)
@@ -111,11 +113,6 @@
 
 #define SMMU_PDE_NEXT_SHIFT		28
 
-/* AHB Arbiter Registers */
-#define AHB_XBAR_CTRL				0xe0
-#define AHB_XBAR_CTRL_SMMU_INIT_DONE_DONE	1
-#define AHB_XBAR_CTRL_SMMU_INIT_DONE_SHIFT	17
-
 #define SMMU_NUM_ASIDS				4
 #define SMMU_TLB_FLUSH_VA_SECTION__MASK		0xffc00000
 #define SMMU_TLB_FLUSH_VA_SECTION__SHIFT	12 /* right shift */
@@ -235,7 +232,7 @@ struct smmu_as {
  * Per SMMU device - IOMMU device
  */
 struct smmu_device {
-	void __iomem	*regs, *regs_ahbarb;
+	void __iomem	*regs;
 	unsigned long	iovmm_base;	/* remappable base address */
 	unsigned long	page_count;	/* total remappable size */
 	spinlock_t	lock;
@@ -252,12 +249,14 @@ struct smmu_device {
 	unsigned long translation_enable_1;
 	unsigned long translation_enable_2;
 	unsigned long asid_security;
+
+	struct device_node *ahb;
 };
 
 static struct smmu_device *smmu_handle; /* unique for a system */
 
 /*
- *	SMMU/AHB register accessors
+ *	SMMU register accessors
  */
 static inline u32 smmu_read(struct smmu_device *smmu, size_t offs)
 {
@@ -268,15 +267,6 @@ static inline void smmu_write(struct smmu_device *smmu, u32 val, size_t offs)
 	writel(val, smmu->regs + offs);
 }
 
-static inline u32 ahb_read(struct smmu_device *smmu, size_t offs)
-{
-	return readl(smmu->regs_ahbarb + offs);
-}
-static inline void ahb_write(struct smmu_device *smmu, u32 val, size_t offs)
-{
-	writel(val, smmu->regs_ahbarb + offs);
-}
-
 #define VA_PAGE_TO_PA(va, page)	\
 	(page_to_phys(page) + ((unsigned long)(va) & ~PAGE_MASK))
 
@@ -370,9 +360,9 @@ static void smmu_flush_regs(struct smmu_device *smmu, int enable)
 	FLUSH_SMMU_REGS(smmu);
 }
 
-static void smmu_setup_regs(struct smmu_device *smmu)
+static int smmu_setup_regs(struct smmu_device *smmu)
 {
-	int i;
+	int i, err;
 	u32 val;
 
 	for (i = 0; i < smmu->num_as; i++) {
@@ -398,10 +388,8 @@ static void smmu_setup_regs(struct smmu_device *smmu)
 
 	smmu_flush_regs(smmu, 1);
 
-	val = ahb_read(smmu, AHB_XBAR_CTRL);
-	val |= AHB_XBAR_CTRL_SMMU_INIT_DONE_DONE <<
-		AHB_XBAR_CTRL_SMMU_INIT_DONE_SHIFT;
-	ahb_write(smmu, val, AHB_XBAR_CTRL);
+	err = tegra_ahb_enable_smmu(smmu->ahb);
+	return err;
 }
 
 static void flush_ptc_and_tlb(struct smmu_device *smmu,
@@ -873,17 +861,18 @@ static int tegra_smmu_resume(struct device *dev)
 {
 	struct smmu_device *smmu = dev_get_drvdata(dev);
 	unsigned long flags;
+	int err;
 
 	spin_lock_irqsave(&smmu->lock, flags);
-	smmu_setup_regs(smmu);
+	err = smmu_setup_regs(smmu);
 	spin_unlock_irqrestore(&smmu->lock, flags);
-	return 0;
+	return err;
 }
 
 static int tegra_smmu_probe(struct platform_device *pdev)
 {
 	struct smmu_device *smmu;
-	struct resource *regs, *regs2, *window;
+	struct resource *regs, *window;
 	struct device *dev = &pdev->dev;
 	int i, err = 0;
 
@@ -893,9 +882,8 @@ static int tegra_smmu_probe(struct platform_device *pdev)
 	BUILD_BUG_ON(PAGE_SHIFT != SMMU_PAGE_SHIFT);
 
 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	regs2 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
-	window = platform_get_resource(pdev, IORESOURCE_MEM, 2);
-	if (!regs || !regs2 || !window) {
+	window = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!regs || !window) {
 		dev_err(dev, "No SMMU resources\n");
 		return -ENODEV;
 	}
@@ -911,14 +899,16 @@ static int tegra_smmu_probe(struct platform_device *pdev)
 	smmu->iovmm_base = (unsigned long)window->start;
 	smmu->page_count = resource_size(window) >> SMMU_PAGE_SHIFT;
 	smmu->regs = devm_ioremap(dev, regs->start, resource_size(regs));
-	smmu->regs_ahbarb = devm_ioremap(dev, regs2->start,
-					 resource_size(regs2));
-	if (!smmu->regs || !smmu->regs_ahbarb) {
+	if (!smmu->regs) {
 		dev_err(dev, "failed to remap SMMU registers\n");
 		err = -ENXIO;
 		goto fail;
 	}
 
+	smmu->ahb = of_parse_phandle(pdev->dev.of_node, "ahb", 0);
+	if (!smmu->ahb)
+		return -ENODEV;
+
 	smmu->translation_enable_0 = ~0;
 	smmu->translation_enable_1 = ~0;
 	smmu->translation_enable_2 = ~0;
@@ -945,7 +935,9 @@ static int tegra_smmu_probe(struct platform_device *pdev)
 		INIT_LIST_HEAD(&as->client);
 	}
 	spin_lock_init(&smmu->lock);
-	smmu_setup_regs(smmu);
+	err = smmu_setup_regs(smmu);
+	if (err)
+		goto fail;
 	platform_set_drvdata(pdev, smmu);
 
 	smmu->avp_vector_page = alloc_page(GFP_KERNEL);
@@ -960,8 +952,6 @@ fail:
 		__free_page(smmu->avp_vector_page);
 	if (smmu->regs)
 		devm_iounmap(dev, smmu->regs);
-	if (smmu->regs_ahbarb)
-		devm_iounmap(dev, smmu->regs_ahbarb);
 	if (smmu && smmu->as) {
 		for (i = 0; i < smmu->num_as; i++) {
 			if (smmu->as[i].pdir_page) {
@@ -993,8 +983,6 @@ static int tegra_smmu_remove(struct platform_device *pdev)
 		__free_page(smmu->avp_vector_page);
 	if (smmu->regs)
 		devm_iounmap(dev, smmu->regs);
-	if (smmu->regs_ahbarb)
-		devm_iounmap(dev, smmu->regs_ahbarb);
 	devm_kfree(dev, smmu);
 	smmu_handle = NULL;
 	return 0;
-- 
1.7.5.4

Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB

[Stephen Warren]

On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
> Use "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> ready, instead of directly aceessing AHB registers.

You need to make the Kconfig option for the SMMU either depend on or
select the TEGRA_AHB option. If you don't, then if someone disables the
AHB driver, the SMMU driver may still build, yet fail to link since the
AHB API it calls doesn't exist.

> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c

> @@ -398,10 +388,8 @@ static void smmu_setup_regs(struct smmu_device *smmu)
>  
>  	smmu_flush_regs(smmu, 1);
>  
> -	val = ahb_read(smmu, AHB_XBAR_CTRL);
> -	val |= AHB_XBAR_CTRL_SMMU_INIT_DONE_DONE <<
> -		AHB_XBAR_CTRL_SMMU_INIT_DONE_SHIFT;
> -	ahb_write(smmu, val, AHB_XBAR_CTRL);
> +	err = tegra_ahb_enable_smmu(smmu->ahb);
> +	return err;

You can just "return tegra_ahb_..." here.

> @@ -911,14 +899,16 @@ static int tegra_smmu_probe(struct platform_device *pdev)

> +	smmu->ahb = of_parse_phandle(pdev->dev.of_node, "ahb", 0);

Hmm, "ahb" should probably be "nvidia,ahb".

I see that neither this patch nor the next patch include binding
documentation that describe this property. Can you please add documentation.

Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB

[Stephen Warren]

On 05/03/2012 11:48 AM, Stephen Warren wrote:
> On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
>> Use "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
>> ready, instead of directly aceessing AHB registers.

Oh, that should be "accessing".

>> @@ -911,14 +899,16 @@ static int tegra_smmu_probe(struct platform_device *pdev)
> 
>> +	smmu->ahb = of_parse_phandle(pdev->dev.of_node, "ahb", 0);
> 
> Hmm, "ahb" should probably be "nvidia,ahb".
> 
> I see that neither this patch nor the next patch include binding
> documentation that describe this property. Can you please add documentation.

Oh, the next patch is just adding the entry to the .dtsi file for the
AHB, so no surprise it doesn't add a binding document for the SMMU!

I see that with this patch, the driver still expects the DMA window to
be represented as a reg property (IORESOURCE_MEM), so if we add a
binding document to this patch it won't be very consistent either:-( And
then, there's the issue of whether the SMMU should be it's own device or
a child of some MC device, since there's non-SMMU functionality in these
registers too. This makes all the SMMU rework need a little more thought.

So, I propose dropping this patch from this series, since this series is
all about adding the AHB driver. We should move this patch to a series
relating to the SMMU driver.

Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB

[Hiroshi Doyu]

From: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
Subject: Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB
Date: Thu, 3 May 2012 19:58:30 +0200
Message-ID: <4FA2C746.5080000-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>

> On 05/03/2012 11:48 AM, Stephen Warren wrote:
> > On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
> >> Use "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> >> ready, instead of directly aceessing AHB registers.
> 
> Oh, that should be "accessing".
> 
> >> @@ -911,14 +899,16 @@ static int tegra_smmu_probe(struct platform_device *pdev)
> > 
> >> +	smmu->ahb = of_parse_phandle(pdev->dev.of_node, "ahb", 0);
> > 
> > Hmm, "ahb" should probably be "nvidia,ahb".
> > 
> > I see that neither this patch nor the next patch include binding
> > documentation that describe this property. Can you please add documentation.
> 
> Oh, the next patch is just adding the entry to the .dtsi file for the
> AHB, so no surprise it doesn't add a binding document for the SMMU!
> 
> I see that with this patch, the driver still expects the DMA window to
> be represented as a reg property (IORESOURCE_MEM), so if we add a
> binding document to this patch it won't be very consistent either:-( And
> then, there's the issue of whether the SMMU should be it's own device or
> a child of some MC device, since there's non-SMMU functionality in these
> registers too. This makes all the SMMU rework need a little more thought.
> 
> So, I propose dropping this patch from this series, since this series is
> all about adding the AHB driver. We should move this patch to a series
> relating to the SMMU driver.

Ok, I'll post the first 3 patches.

Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB

[Hiroshi Doyu]

From: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
Subject: Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB
Date: Thu, 3 May 2012 19:48:25 +0200
Message-ID: <4FA2C4E9.2080509-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>

> On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
> > Use "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> > ready, instead of directly aceessing AHB registers.
> 
> You need to make the Kconfig option for the SMMU either depend on or
> select the TEGRA_AHB option. If you don't, then if someone disables the
> AHB driver, the SMMU driver may still build, yet fail to link since the
> AHB API it calls doesn't exist.
> 
> > diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> 
> > @@ -398,10 +388,8 @@ static void smmu_setup_regs(struct smmu_device *smmu)
> >  
> >  	smmu_flush_regs(smmu, 1);
> >  
> > -	val = ahb_read(smmu, AHB_XBAR_CTRL);
> > -	val |= AHB_XBAR_CTRL_SMMU_INIT_DONE_DONE <<
> > -		AHB_XBAR_CTRL_SMMU_INIT_DONE_SHIFT;
> > -	ahb_write(smmu, val, AHB_XBAR_CTRL);
> > +	err = tegra_ahb_enable_smmu(smmu->ahb);
> > +	return err;
> 
> You can just "return tegra_ahb_..." here.
> 
> > @@ -911,14 +899,16 @@ static int tegra_smmu_probe(struct platform_device *pdev)
> 
> > +	smmu->ahb = of_parse_phandle(pdev->dev.of_node, "ahb", 0);
> 
> Hmm, "ahb" should probably be "nvidia,ahb".
> 
> I see that neither this patch nor the next patch include binding
> documentation that describe this property. Can you please add documentation.

There will be the tegra Memory Controller(MC) patches following, which
will change the way DT is passed, where SMMU/dt is passed from
MC.

Can we wait for the following MC patches, not haveing doc for this
patch?

Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB

[Hiroshi Doyu]

From: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
Subject: Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB
Date: Thu, 3 May 2012 19:48:25 +0200
Message-ID: <4FA2C4E9.2080509-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>

> On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
> > Use "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> > ready, instead of directly aceessing AHB registers.
> 
> You need to make the Kconfig option for the SMMU either depend on or
> select the TEGRA_AHB option. If you don't, then if someone disables the
> AHB driver, the SMMU driver may still build, yet fail to link since the
> AHB API it calls doesn't exist.
> 
> > diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> 
> > @@ -398,10 +388,8 @@ static void smmu_setup_regs(struct smmu_device *smmu)
> >  
> >  	smmu_flush_regs(smmu, 1);
> >  
> > -	val = ahb_read(smmu, AHB_XBAR_CTRL);
> > -	val |= AHB_XBAR_CTRL_SMMU_INIT_DONE_DONE <<
> > -		AHB_XBAR_CTRL_SMMU_INIT_DONE_SHIFT;
> > -	ahb_write(smmu, val, AHB_XBAR_CTRL);
> > +	err = tegra_ahb_enable_smmu(smmu->ahb);
> > +	return err;
> 
> You can just "return tegra_ahb_..." here.
> 
> > @@ -911,14 +899,16 @@ static int tegra_smmu_probe(struct platform_device *pdev)
> 
> > +	smmu->ahb = of_parse_phandle(pdev->dev.of_node, "ahb", 0);
> 
> Hmm, "ahb" should probably be "nvidia,ahb".

Does this mean the following in dts?

	ahb: ahb@6000c004 {
		compatible = "nvidia,tegra30-ahb";
		reg = <0x6000c004 0x14c>; /* AHB Arbitration + Gizmo Controller */
	};

	smmu: smmu@7000f000 {
		nvidia,ahb = &ahb;
	};      ^^^^^^^^^^

Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB

[Stephen Warren]

On 05/04/2012 12:33 AM, Hiroshi Doyu wrote:
> Stephen Warren wrote at Thu, 3 May 2012 19:48:25 +0200:
>> On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
>>> Use "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
>>> ready, instead of directly aceessing AHB registers.
...
>>> @@ -911,14 +899,16 @@ static int tegra_smmu_probe(struct platform_device *pdev)
>>
>>> +	smmu->ahb = of_parse_phandle(pdev->dev.of_node, "ahb", 0);
>>
>> Hmm, "ahb" should probably be "nvidia,ahb".
> 
> Does this mean the following in dts?
> 
> 	ahb: ahb@6000c004 {
> 		compatible = "nvidia,tegra30-ahb";
> 		reg = <0x6000c004 0x14c>; /* AHB Arbitration + Gizmo Controller */
> 	};
> 
> 	smmu: smmu@7000f000 {
> 		nvidia,ahb = &ahb;
> 	};      ^^^^^^^^^^
> 

Yes.

[PATCHv3 4/4] ARM: dt: tegra: Add device tree support for AHB

[Hiroshi DOYU]

Add AHB entry for tegra20/30.

Signed-off-by: Hiroshi DOYU <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
 arch/arm/boot/dts/tegra20.dtsi |    5 +++++
 arch/arm/boot/dts/tegra30.dtsi |    5 +++++
 2 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/arch/arm/boot/dts/tegra20.dtsi b/arch/arm/boot/dts/tegra20.dtsi
index 52cab08..ea6de57 100644
--- a/arch/arm/boot/dts/tegra20.dtsi
+++ b/arch/arm/boot/dts/tegra20.dtsi
@@ -212,5 +212,10 @@
 		reg = < 0x7000f000 0x00000100    /* controller registers */
 		        0x58000000 0x02000000 >; /* GART aperture */
 	};
+
+	ahb: ahb@6000c004 {
+		compatible = "nvidia,tegra20-ahb";
+		reg = <0x6000c004 0x10c>; /* AHB Arbitration + Gizmo Controller */
+	};
 };
 
diff --git a/arch/arm/boot/dts/tegra30.dtsi b/arch/arm/boot/dts/tegra30.dtsi
index 15200a9..9d650fb 100644
--- a/arch/arm/boot/dts/tegra30.dtsi
+++ b/arch/arm/boot/dts/tegra30.dtsi
@@ -224,4 +224,9 @@
 			nvidia,ahub-cif-ids = <8 8>;
 		};
 	};
+
+	ahb: ahb@6000c004 {
+		compatible = "nvidia,tegra30-ahb";
+		reg = <0x6000c004 0x14c>; /* AHB Arbitration + Gizmo Controller */
+	};
 };
-- 
1.7.5.4

Re: [PATCHv3 4/4] ARM: dt: tegra: Add device tree support for AHB

[Stephen Warren]

On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
> Add AHB entry for tegra20/30.

This looks OK. I can take it through the Tegra tree once the review
issues are fixed.

Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver

[Stephen Warren]

On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
> Tegra AHB Bus conforms to the AMBA Specification (Rev 2.0) Advanced
> High-performance Bus (AHB) architecture.
> 
> The AHB Arbiter controls AHB bus master arbitration. This effectively
> forms a second level of arbitration for access to the memory
> controller through the AHB Slave Memory device. The AHB pre-fetch
> logic can be configured to enhance performance for devices doing
> sequential access. Each AHB master is assigned to either the high or
> low priority bin. Both Tegra20/30 have this AHB bus.
> 
> Some of configuration param could be passed from DT too.

> diff --git a/drivers/amba/tegra-ahb.c b/drivers/amba/tegra-ahb.c
> +static u32 tegra_ahb_gizmo[] = {

const?

> +static int __init tegra_ahb_module_init(void)
> +{
> +	return platform_driver_register(&tegra_ahb_driver);
> +}
> +postcore_initcall(tegra_ahb_module_init);

Can this be a module_init() instead of postcore_initcall()?

> +
> +static void __exit tegra_ahb_module_exit(void)
> +{
> +	platform_driver_unregister(&tegra_ahb_driver);
> +}
> +module_exit(tegra_ahb_module_exit);

If so, all of the previous two quoted chunks can be replaced with just:

module_platform_driver(tegra_ahb_module_init);

Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver

[Hiroshi Doyu]

From: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
Subject: Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver
Date: Thu, 3 May 2012 19:41:35 +0200
Message-ID: <4FA2C34F.5060406-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>

> On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
> > Tegra AHB Bus conforms to the AMBA Specification (Rev 2.0) Advanced
> > High-performance Bus (AHB) architecture.
> > 
> > The AHB Arbiter controls AHB bus master arbitration. This effectively
> > forms a second level of arbitration for access to the memory
> > controller through the AHB Slave Memory device. The AHB pre-fetch
> > logic can be configured to enhance performance for devices doing
> > sequential access. Each AHB master is assigned to either the high or
> > low priority bin. Both Tegra20/30 have this AHB bus.
> > 
> > Some of configuration param could be passed from DT too.
> 
> > diff --git a/drivers/amba/tegra-ahb.c b/drivers/amba/tegra-ahb.c
> > +static u32 tegra_ahb_gizmo[] = {
> 
> const?

Yes.

> > +static int __init tegra_ahb_module_init(void)
> > +{
> > +	return platform_driver_register(&tegra_ahb_driver);
> > +}
> > +postcore_initcall(tegra_ahb_module_init);
> 
> Can this be a module_init() instead of postcore_initcall()?

Since this driver configures prefetch size from AHB client devices,
it's better to make this driver available before other AHB client
drivers get ready. So "postcore_initcall()" seems to make sense if
there's no other better initcall.

> > +
> > +static void __exit tegra_ahb_module_exit(void)
> > +{
> > +	platform_driver_unregister(&tegra_ahb_driver);
> > +}
> > +module_exit(tegra_ahb_module_exit);
> 
> If so, all of the previous two quoted chunks can be replaced with just:
> 
> module_platform_driver(tegra_ahb_module_init);

Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver

[Stephen Warren]

On 05/04/2012 12:17 AM, Hiroshi Doyu wrote:
> Stephen Warren wrote at Thu, 3 May 2012 19:41:35 +0200:
>> On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
>>> Tegra AHB Bus conforms to the AMBA Specification (Rev 2.0) Advanced
>>> High-performance Bus (AHB) architecture.
...
>>> +static int __init tegra_ahb_module_init(void)
>>> +{
>>> +	return platform_driver_register(&tegra_ahb_driver);
>>> +}
>>> +postcore_initcall(tegra_ahb_module_init);
>>
>> Can this be a module_init() instead of postcore_initcall()?
> 
> Since this driver configures prefetch size from AHB client devices,
> it's better to make this driver available before other AHB client
> drivers get ready. So "postcore_initcall()" seems to make sense if
> there's no other better initcall.

I believe this only affects when the driver is registered and has no
influence over when the device itself is probed.

When booting with board files rather than DT, it was possible to
register drivers and platform devices early using various initcalls to
control the order. However, with DT, I believe all the devices are
instantiated from DT at the same time (well, one by one in whatever
order as the DT is parsed), so the time when the driver is registered
isn't relevant.

So, if the other AHB devices really need this AHB driver to initialize
first, you'd better move all the AHB devices inside the AHB node in DT,
so that the AHB driver can influence when the children get probed.
Still, I'd suggest leaving that to a later patch, since everything
clearly works fine right now without this driver even existing.

>>> +
>>> +static void __exit tegra_ahb_module_exit(void)
>>> +{
>>> +	platform_driver_unregister(&tegra_ahb_driver);
>>> +}
>>> +module_exit(tegra_ahb_module_exit);
>>
>> If so, all of the previous two quoted chunks can be replaced with just:
>>
>> module_platform_driver(tegra_ahb_module_init);

Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver

[Hiroshi Doyu]

On Fri, 4 May 2012 18:48:56 +0200
Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> wrote:

> On 05/04/2012 12:17 AM, Hiroshi Doyu wrote:
> > Stephen Warren wrote at Thu, 3 May 2012 19:41:35 +0200:
> >> On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
> >>> Tegra AHB Bus conforms to the AMBA Specification (Rev 2.0) Advanced
> >>> High-performance Bus (AHB) architecture.
> ...
> >>> +static int __init tegra_ahb_module_init(void)
> >>> +{
> >>> +	return platform_driver_register(&tegra_ahb_driver);
> >>> +}
> >>> +postcore_initcall(tegra_ahb_module_init);
> >>
> >> Can this be a module_init() instead of postcore_initcall()?
> > 
> > Since this driver configures prefetch size from AHB client devices,
> > it's better to make this driver available before other AHB client
> > drivers get ready. So "postcore_initcall()" seems to make sense if
> > there's no other better initcall.
> 
> I believe this only affects when the driver is registered and has no
> influence over when the device itself is probed.
> 
> When booting with board files rather than DT, it was possible to
> register drivers and platform devices early using various initcalls to
> control the order. However, with DT, I believe all the devices are
> instantiated from DT at the same time (well, one by one in whatever
> order as the DT is parsed), so the time when the driver is registered
> isn't relevant.
> 
> So, if the other AHB devices really need this AHB driver to initialize
> first, you'd better move all the AHB devices inside the AHB node in DT,
> so that the AHB driver can influence when the children get probed.
> Still, I'd suggest leaving that to a later patch, since everything
> clearly works fine right now without this driver even existing.

Ok, I'll use module_platform_driver(tegra_ahb_driver). These order would be revisited.

Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver

[Stephen Warren]

On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
> Tegra AHB Bus conforms to the AMBA Specification (Rev 2.0) Advanced
> High-performance Bus (AHB) architecture.
> 
> The AHB Arbiter controls AHB bus master arbitration. This effectively
> forms a second level of arbitration for access to the memory
> controller through the AHB Slave Memory device. The AHB pre-fetch
> logic can be configured to enhance performance for devices doing
> sequential access. Each AHB master is assigned to either the high or
> low priority bin. Both Tegra20/30 have this AHB bus.
> 
> Some of configuration param could be passed from DT too.

This patch should add
Documentation/devicetree/bindings/arm/tegra/tegra20-ahb.txt to describe
the DT binding.

Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver

[Hiroshi Doyu]

From: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
Subject: Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver
Date: Thu, 3 May 2012 19:59:33 +0200
Message-ID: <4FA2C785.2080703-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>

> On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
> > Tegra AHB Bus conforms to the AMBA Specification (Rev 2.0) Advanced
> > High-performance Bus (AHB) architecture.
> > 
> > The AHB Arbiter controls AHB bus master arbitration. This effectively
> > forms a second level of arbitration for access to the memory
> > controller through the AHB Slave Memory device. The AHB pre-fetch
> > logic can be configured to enhance performance for devices doing
> > sequential access. Each AHB master is assigned to either the high or
> > low priority bin. Both Tegra20/30 have this AHB bus.
> > 
> > Some of configuration param could be passed from DT too.
> 
> This patch should add
> Documentation/devicetree/bindings/arm/tegra/tegra20-ahb.txt to describe
> the DT binding.

From 'dts' POV, there's no difference between tegra20 and
tegra30. They just have a register range. Is
"../bindings/arm/tegra/tegra-ahb.txt" ok, instead of having both
tegra{20,30}-ahb.txt?

Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver

[Arnd Bergmann]

On Friday 04 May 2012, Hiroshi Doyu wrote:
> > This patch should add
> > Documentation/devicetree/bindings/arm/tegra/tegra20-ahb.txt to describe
> > the DT binding.
> 
> From 'dts' POV, there's no difference between tegra20 and
> tegra30. They just have a register range. Is
> "../bindings/arm/tegra/tegra-ahb.txt" ok, instead of having both
> tegra{20,30}-ahb.txt?

I think either one is ok. Just calling it tegra20-ahb.txt would be
fine too because tegra30 is compatible to that.

	Arnd

Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver

[Stephen Warren]

On 05/04/2012 12:40 AM, Hiroshi Doyu wrote:
> From: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
> Subject: Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver
> Date: Thu, 3 May 2012 19:59:33 +0200
> Message-ID: <4FA2C785.2080703-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
> 
>> On 05/03/2012 10:05 AM, Hiroshi DOYU wrote:
>>> Tegra AHB Bus conforms to the AMBA Specification (Rev 2.0) Advanced
>>> High-performance Bus (AHB) architecture.
>>>
>>> The AHB Arbiter controls AHB bus master arbitration. This effectively
>>> forms a second level of arbitration for access to the memory
>>> controller through the AHB Slave Memory device. The AHB pre-fetch
>>> logic can be configured to enhance performance for devices doing
>>> sequential access. Each AHB master is assigned to either the high or
>>> low priority bin. Both Tegra20/30 have this AHB bus.
>>>
>>> Some of configuration param could be passed from DT too.
>>
>> This patch should add
>> Documentation/devicetree/bindings/arm/tegra/tegra20-ahb.txt to describe
>> the DT binding.
> 
> From 'dts' POV, there's no difference between tegra20 and
> tegra30. They just have a register range. Is
> "../bindings/arm/tegra/tegra-ahb.txt" ok, instead of having both
> tegra{20,30}-ahb.txt?

Personally, I prefer to name files using the exact compatible value of
the first SoC version that introduced the HW. This allows e.g.
"tegra40-ahb.txt" to be introduced without making "tegra-ahb.txt" no
longer fully general.

[PATCHv3 1/4] ARM: tegra: Add AHB driver

[Hiroshi DOYU]

The AHB Bus conforms to the AMBA Specification (Rev 2.0) Advanced
High-performance Bus (AHB) architecture.

The AHB Arbiter controls AHB bus master arbitration. This effectively
forms a second level of arbitration for access to the memory
controller through the AHB Slave Memory device. The AHB pre-fetch
logic can be configured to enhance performance for devices doing
sequential access. Each AHB master is assigned to either the high or
low priority bin. Both Tegra20/30 have this AHB bus.

Some of configuration param could be passed from DT too.

Signed-off-by: Hiroshi DOYU <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Cc: Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>
Cc: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
---
v4:
Fixed the comments from Felipe/Russell.
This is now located under drivers/platform/arm.
v3:
Use platform_device to get info from dt dynamically.(Felipe/Arnd)

Signed-off-by: Hiroshi DOYU <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
 drivers/platform/Kconfig         |    5 +
 drivers/platform/Makefile        |    1 +
 drivers/platform/arm/Kconfig     |    8 +
 drivers/platform/arm/Makefile    |    5 +
 drivers/platform/arm/tegra-ahb.c |  278 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 297 insertions(+), 0 deletions(-)

diff --git a/drivers/platform/Kconfig b/drivers/platform/Kconfig
index 8390dca..8b96a77 100644
--- a/drivers/platform/Kconfig
+++ b/drivers/platform/Kconfig
@@ -1,3 +1,8 @@
 if X86
 source "drivers/platform/x86/Kconfig"
 endif
+
+if ARM
+source "drivers/platform/arm/Kconfig"
+endif
+
diff --git a/drivers/platform/Makefile b/drivers/platform/Makefile
index 782953a..7a2b16f 100644
--- a/drivers/platform/Makefile
+++ b/drivers/platform/Makefile
@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_X86)		+= x86/
+obj-$(CONFIG_ARM)		+= arm/
diff --git a/drivers/platform/arm/Kconfig b/drivers/platform/arm/Kconfig
new file mode 100644
index 0000000..0af31db
--- /dev/null
+++ b/drivers/platform/arm/Kconfig
@@ -0,0 +1,8 @@
+config TEGRA_AHB
+	bool "Enable AHB driver for NVIDIA Tegra SoCs"
+	depends on ARCH_TEGRA
+	default y
+	help
+	  Adds AHB configuration functionality for NVIDIA Tegra SoCs,
+	  which controls AHB bus master arbitration and some
+	  perfomance parameters(priority, prefech size).
diff --git a/drivers/platform/arm/Makefile b/drivers/platform/arm/Makefile
new file mode 100644
index 0000000..3535f56
--- /dev/null
+++ b/drivers/platform/arm/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for linux/drivers/platform/arm
+# ARM Platform-Specific Drivers
+#
+obj-$(CONFIG_TEGRA_AHB)		+= tegra-ahb.o
diff --git a/drivers/platform/arm/tegra-ahb.c b/drivers/platform/arm/tegra-ahb.c
new file mode 100644
index 0000000..dcad2ec
--- /dev/null
+++ b/drivers/platform/arm/tegra-ahb.c
@@ -0,0 +1,278 @@
+/*
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Author:
+ *	Jay Cheng <jacheng-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
+ *	James Wylder <james.wylder-3WKxDLwmzFNWk0Htik3J/w@public.gmane.org>
+ *	Benoit Goby <benoit-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
+ *	Colin Cross <ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
+ *	Hiroshi DOYU <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#include <mach/iomap.h>
+
+#define DRV_NAME "tegra-ahb"
+
+#define AHB_ARBITRATION_DISABLE		0x00
+#define AHB_ARBITRATION_PRIORITY_CTRL	0x04
+#define   AHB_PRIORITY_WEIGHT(x)	(((x) & 0x7) << 29)
+#define   PRIORITY_SELECT_USB BIT(6)
+#define   PRIORITY_SELECT_USB2 BIT(18)
+#define   PRIORITY_SELECT_USB3 BIT(17)
+
+#define AHB_GIZMO_AHB_MEM		0x0c
+#define   ENB_FAST_REARBITRATE BIT(2)
+#define   DONT_SPLIT_AHB_WR     BIT(7)
+
+#define AHB_GIZMO_APB_DMA		0x10
+#define AHB_GIZMO_IDE			0x18
+#define AHB_GIZMO_USB			0x1c
+#define AHB_GIZMO_AHB_XBAR_BRIDGE	0x20
+#define AHB_GIZMO_CPU_AHB_BRIDGE	0x24
+#define AHB_GIZMO_COP_AHB_BRIDGE	0x28
+#define AHB_GIZMO_XBAR_APB_CTLR		0x2c
+#define AHB_GIZMO_VCP_AHB_BRIDGE	0x30
+#define AHB_GIZMO_NAND			0x3c
+#define AHB_GIZMO_SDMMC4		0x44
+#define AHB_GIZMO_XIO			0x48
+#define AHB_GIZMO_BSEV			0x60
+#define AHB_GIZMO_BSEA			0x70
+#define AHB_GIZMO_NOR			0x74
+#define AHB_GIZMO_USB2			0x78
+#define AHB_GIZMO_USB3			0x7c
+#define   IMMEDIATE	BIT(18)
+
+#define AHB_GIZMO_SDMMC1		0x80
+#define AHB_GIZMO_SDMMC2		0x84
+#define AHB_GIZMO_SDMMC3		0x88
+#define AHB_MEM_PREFETCH_CFG_X		0xd8
+#define AHB_ARBITRATION_XBAR_CTRL	0xdc
+#define AHB_MEM_PREFETCH_CFG3		0xe0
+#define AHB_MEM_PREFETCH_CFG4		0xe4
+#define AHB_MEM_PREFETCH_CFG1		0xec
+#define AHB_MEM_PREFETCH_CFG2		0xf0
+#define   PREFETCH_ENB	BIT(31)
+#define   MST_ID(x)	(((x) & 0x1f) << 26)
+#define   AHBDMA_MST_ID	MST_ID(5)
+#define   USB_MST_ID	MST_ID(6)
+#define   USB2_MST_ID	MST_ID(18)
+#define   USB3_MST_ID	MST_ID(17)
+#define   ADDR_BNDRY(x)	(((x) & 0xf) << 21)
+#define   INACTIVITY_TIMEOUT(x)	(((x) & 0xffff) << 0)
+
+#define AHB_ARBITRATION_AHB_MEM_WRQUE_MST_ID	0xf8
+
+static u32 tegra_ahb_gizmo[] = {
+	AHB_ARBITRATION_DISABLE,
+	AHB_ARBITRATION_PRIORITY_CTRL,
+	AHB_GIZMO_AHB_MEM,
+	AHB_GIZMO_APB_DMA,
+	AHB_GIZMO_IDE,
+	AHB_GIZMO_USB,
+	AHB_GIZMO_AHB_XBAR_BRIDGE,
+	AHB_GIZMO_CPU_AHB_BRIDGE,
+	AHB_GIZMO_COP_AHB_BRIDGE,
+	AHB_GIZMO_XBAR_APB_CTLR,
+	AHB_GIZMO_VCP_AHB_BRIDGE,
+	AHB_GIZMO_NAND,
+	AHB_GIZMO_SDMMC4,
+	AHB_GIZMO_XIO,
+	AHB_GIZMO_BSEV,
+	AHB_GIZMO_BSEA,
+	AHB_GIZMO_NOR,
+	AHB_GIZMO_USB2,
+	AHB_GIZMO_USB3,
+	AHB_GIZMO_SDMMC1,
+	AHB_GIZMO_SDMMC2,
+	AHB_GIZMO_SDMMC3,
+	AHB_MEM_PREFETCH_CFG_X,
+	AHB_ARBITRATION_XBAR_CTRL,
+	AHB_MEM_PREFETCH_CFG3,
+	AHB_MEM_PREFETCH_CFG4,
+	AHB_MEM_PREFETCH_CFG1,
+	AHB_MEM_PREFETCH_CFG2,
+	AHB_ARBITRATION_AHB_MEM_WRQUE_MST_ID,
+};
+
+struct tegra_ahb {
+	void __iomem	*regs;
+	void		*ctx;
+	struct device	*dev;
+};
+
+static inline u32 gizmo_readl(struct tegra_ahb *ahb, u32 offset)
+{
+	return readl(ahb->regs + offset);
+}
+
+static inline void gizmo_writel(struct tegra_ahb *ahb, u32 value, u32 offset)
+{
+	writel(value, ahb->regs + offset);
+}
+
+static int tegra_ahb_suspend(struct device *dev)
+{
+	int i;
+	struct tegra_ahb *ahb = dev_get_drvdata(dev);
+	u32 *p = ahb->ctx;
+
+	for (i = 0; i < ARRAY_SIZE(tegra_ahb_gizmo); i++)
+		p[i] = gizmo_readl(ahb, tegra_ahb_gizmo[i]);
+	return 0;
+}
+
+static int tegra_ahb_resume(struct device *dev)
+{
+	int i;
+	struct tegra_ahb *ahb = dev_get_drvdata(dev);
+	u32 *p = ahb->ctx;
+
+	for (i = 0; i < ARRAY_SIZE(tegra_ahb_gizmo); i++)
+		gizmo_writel(ahb, p[i], tegra_ahb_gizmo[i]);
+	return 0;
+}
+
+static UNIVERSAL_DEV_PM_OPS(tegra_ahb_pm,
+			    tegra_ahb_suspend,
+			    tegra_ahb_resume, NULL);
+
+static void tegra_ahb_gizmo_init(struct tegra_ahb *ahb)
+{
+	u32 val;
+
+	val = gizmo_readl(ahb, AHB_GIZMO_AHB_MEM);
+	val |= ENB_FAST_REARBITRATE | IMMEDIATE | DONT_SPLIT_AHB_WR;
+	gizmo_writel(ahb, val, AHB_GIZMO_AHB_MEM);
+
+	val = gizmo_readl(ahb, AHB_GIZMO_USB);
+	val |= IMMEDIATE;
+	gizmo_writel(ahb, val, AHB_GIZMO_USB);
+
+	val = gizmo_readl(ahb, AHB_GIZMO_USB2);
+	val |= IMMEDIATE;
+	gizmo_writel(ahb, val, AHB_GIZMO_USB2);
+
+	val = gizmo_readl(ahb, AHB_GIZMO_USB3);
+	val |= IMMEDIATE;
+	gizmo_writel(ahb, val, AHB_GIZMO_USB3);
+
+	val = gizmo_readl(ahb, AHB_ARBITRATION_PRIORITY_CTRL);
+	val |= PRIORITY_SELECT_USB |
+		PRIORITY_SELECT_USB2 |
+		PRIORITY_SELECT_USB3 |
+		AHB_PRIORITY_WEIGHT(7);
+	gizmo_writel(ahb, val, AHB_ARBITRATION_PRIORITY_CTRL);
+
+	val = gizmo_readl(ahb, AHB_MEM_PREFETCH_CFG1);
+	val &= ~MST_ID(~0);
+	val |= PREFETCH_ENB |
+		AHBDMA_MST_ID |
+		ADDR_BNDRY(0xc) |
+		INACTIVITY_TIMEOUT(0x1000);
+	gizmo_writel(ahb, val, AHB_MEM_PREFETCH_CFG1);
+
+	val = gizmo_readl(ahb, AHB_MEM_PREFETCH_CFG2);
+	val &= ~MST_ID(~0);
+	val |= PREFETCH_ENB |
+		USB_MST_ID |
+		ADDR_BNDRY(0xc) |
+		INACTIVITY_TIMEOUT(0x1000);
+	gizmo_writel(ahb, val, AHB_MEM_PREFETCH_CFG2);
+
+	val = gizmo_readl(ahb, AHB_MEM_PREFETCH_CFG3);
+	val &= ~MST_ID(~0);
+	val |= PREFETCH_ENB |
+		USB3_MST_ID |
+		ADDR_BNDRY(0xc) |
+		INACTIVITY_TIMEOUT(0x1000);
+	gizmo_writel(ahb, val, AHB_MEM_PREFETCH_CFG3);
+
+	val = gizmo_readl(ahb, AHB_MEM_PREFETCH_CFG4);
+	val &= ~MST_ID(~0);
+	val |= PREFETCH_ENB |
+		USB2_MST_ID |
+		ADDR_BNDRY(0xc) |
+		INACTIVITY_TIMEOUT(0x1000);
+	gizmo_writel(ahb, val, AHB_MEM_PREFETCH_CFG4);
+}
+
+static int __devinit tegra_ahb_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct tegra_ahb *ahb;
+	size_t bytes;
+
+	bytes = sizeof(*ahb) + sizeof(u32) * ARRAY_SIZE(tegra_ahb_gizmo);
+	ahb = devm_kzalloc(&pdev->dev, bytes, GFP_KERNEL);
+	if (!ahb)
+		return -ENOMEM;
+	ahb->ctx = ahb + 1;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+	ahb->regs = devm_request_and_ioremap(&pdev->dev, res);
+	if (!ahb->regs)
+		return -EBUSY;
+
+	ahb->dev = &pdev->dev;
+	platform_set_drvdata(pdev, ahb);
+	tegra_ahb_gizmo_init(ahb);
+	return 0;
+}
+
+static int __devexit tegra_ahb_remove(struct platform_device *pdev)
+{
+	platform_set_drvdata(pdev, NULL);
+	return 0;
+}
+
+static const struct of_device_id tegra_ahb_of_match[] __devinitconst = {
+	{ .compatible = "nvidia,tegra30-ahb", },
+	{ .compatible = "nvidia,tegra20-ahb", },
+	{},
+};
+
+static struct platform_driver tegra_ahb_driver = {
+	.probe = tegra_ahb_probe,
+	.remove = __devexit_p(tegra_ahb_remove),
+	.driver = {
+		.name = DRV_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = tegra_ahb_of_match,
+		.pm = &tegra_ahb_pm,
+	},
+};
+
+static int __init tegra_ahb_init(void)
+{
+	return platform_driver_register(&tegra_ahb_driver);
+}
+postcore_initcall(tegra_ahb_init);
+
+static void __exit tegra_ahb_exit(void)
+{
+	platform_driver_unregister(&tegra_ahb_driver);
+}
+module_exit(tegra_ahb_exit);
+
+MODULE_AUTHOR("Hiroshi DOYU <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>");
+MODULE_DESCRIPTION("Tegra AHB driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRV_NAME);
-- 
1.7.5.4

[PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Hiroshi DOYU]

Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
ready.

Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
Cc: Felipe Balbi <balbi@ti.com>
---
 arch/arm/mach-tegra/include/mach/tegra-ahb.h |   19 +++++++++++++++++++
 drivers/platform/arm/tegra-ahb.c             |   24 ++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-tegra/include/mach/tegra-ahb.h b/arch/arm/mach-tegra/include/mach/tegra-ahb.h
new file mode 100644
index 0000000..296688c
--- /dev/null
+++ b/arch/arm/mach-tegra/include/mach/tegra-ahb.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#ifndef __MACH_TEGRA_AHB_H__
+#define __MACH_TEGRA_AHB_H__
+
+extern int tegra_ahb_enable_smmu(void);
+
+#endif	/* __MACH_TEGRA_AHB_H__ */
diff --git a/drivers/platform/arm/tegra-ahb.c b/drivers/platform/arm/tegra-ahb.c
index dcad2ec..7ad9dfd 100644
--- a/drivers/platform/arm/tegra-ahb.c
+++ b/drivers/platform/arm/tegra-ahb.c
@@ -78,6 +78,10 @@
 
 #define AHB_ARBITRATION_AHB_MEM_WRQUE_MST_ID	0xf8
 
+#define AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE BIT(17)
+
+static struct platform_driver tegra_ahb_driver;
+
 static u32 tegra_ahb_gizmo[] = {
 	AHB_ARBITRATION_DISABLE,
 	AHB_ARBITRATION_PRIORITY_CTRL,
@@ -126,6 +130,26 @@ static inline void gizmo_writel(struct tegra_ahb *ahb, u32 value, u32 offset)
 	writel(value, ahb->regs + offset);
 }
 
+#ifdef CONFIG_ARCH_TEGRA_3x_SOC
+static int __tegra_ahb_enable_smmu(struct device *dev, void *data)
+{
+	u32 val;
+	struct tegra_ahb *ahb = dev_get_drvdata(dev);
+
+	val = gizmo_readl(ahb, AHB_ARBITRATION_XBAR_CTRL);
+	val |= AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE;
+	gizmo_writel(ahb, val, AHB_ARBITRATION_XBAR_CTRL);
+	return 0;
+}
+
+int tegra_ahb_enable_smmu(void)
+{
+	return driver_for_each_device(&tegra_ahb_driver.driver, NULL, NULL,
+				      __tegra_ahb_enable_smmu);
+}
+EXPORT_SYMBOL(tegra_ahb_enable_smmu);
+#endif
+
 static int tegra_ahb_suspend(struct device *dev)
 {
 	int i;
-- 
1.7.5.4

Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 3410 bytes --]

Hi,

On Wed, Apr 25, 2012 at 02:07:37PM +0300, Hiroshi DOYU wrote:
> Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> ready.
> 
> Signed-off-by: Hiroshi DOYU <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> Cc: Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>
> ---
>  arch/arm/mach-tegra/include/mach/tegra-ahb.h |   19 +++++++++++++++++++
>  drivers/platform/arm/tegra-ahb.c             |   24 ++++++++++++++++++++++++
>  2 files changed, 43 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/mach-tegra/include/mach/tegra-ahb.h b/arch/arm/mach-tegra/include/mach/tegra-ahb.h
> new file mode 100644
> index 0000000..296688c
> --- /dev/null
> +++ b/arch/arm/mach-tegra/include/mach/tegra-ahb.h
> @@ -0,0 +1,19 @@
> +/*
> + * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope 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.
> + */
> +
> +#ifndef __MACH_TEGRA_AHB_H__
> +#define __MACH_TEGRA_AHB_H__
> +
> +extern int tegra_ahb_enable_smmu(void);
> +
> +#endif	/* __MACH_TEGRA_AHB_H__ */
> diff --git a/drivers/platform/arm/tegra-ahb.c b/drivers/platform/arm/tegra-ahb.c
> index dcad2ec..7ad9dfd 100644
> --- a/drivers/platform/arm/tegra-ahb.c
> +++ b/drivers/platform/arm/tegra-ahb.c
> @@ -78,6 +78,10 @@
>  
>  #define AHB_ARBITRATION_AHB_MEM_WRQUE_MST_ID	0xf8
>  
> +#define AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE BIT(17)
> +
> +static struct platform_driver tegra_ahb_driver;
> +
>  static u32 tegra_ahb_gizmo[] = {
>  	AHB_ARBITRATION_DISABLE,
>  	AHB_ARBITRATION_PRIORITY_CTRL,
> @@ -126,6 +130,26 @@ static inline void gizmo_writel(struct tegra_ahb *ahb, u32 value, u32 offset)
>  	writel(value, ahb->regs + offset);
>  }
>  
> +#ifdef CONFIG_ARCH_TEGRA_3x_SOC
> +static int __tegra_ahb_enable_smmu(struct device *dev, void *data)
> +{
> +	u32 val;
> +	struct tegra_ahb *ahb = dev_get_drvdata(dev);
> +
> +	val = gizmo_readl(ahb, AHB_ARBITRATION_XBAR_CTRL);
> +	val |= AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE;
> +	gizmo_writel(ahb, val, AHB_ARBITRATION_XBAR_CTRL);
> +	return 0;
> +}
> +
> +int tegra_ahb_enable_smmu(void)
> +{
> +	return driver_for_each_device(&tegra_ahb_driver.driver, NULL, NULL,
> +				      __tegra_ahb_enable_smmu);
> +}
> +EXPORT_SYMBOL(tegra_ahb_enable_smmu);
> +#endif

this is still not correct. If you will always call this whenever you run
on tegra 3, why do you even expose this function ? You can use your
compatible flag to do runtime detection of where you're running and call
this accordingly. Something like:

static const struct of_device_id tegra_ahb_match_table[] = {
{
	.compatible = "nvidia,tegra2",
}, {
	.compatible = "nvidia,tegra3",
	.data	= AHB_HAS_SMMU,
},
{  }
};

or something similar, then on probe, you can capture your id and check
if that bit is true, if it is just call tegra_ahb_enable_smmu(), you
really don't need all this trickery with driver_for_each_device().

-- 
balbi

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Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Stephen Warren]

On 04/25/2012 05:29 AM, Felipe Balbi wrote:
> Hi,
> 
> On Wed, Apr 25, 2012 at 02:07:37PM +0300, Hiroshi DOYU wrote:
>> Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
>> ready.

>> +#ifdef CONFIG_ARCH_TEGRA_3x_SOC
>> +static int __tegra_ahb_enable_smmu(struct device *dev, void *data)
>> +{
>> +	u32 val;
>> +	struct tegra_ahb *ahb = dev_get_drvdata(dev);
>> +
>> +	val = gizmo_readl(ahb, AHB_ARBITRATION_XBAR_CTRL);
>> +	val |= AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE;
>> +	gizmo_writel(ahb, val, AHB_ARBITRATION_XBAR_CTRL);
>> +	return 0;
>> +}
>> +
>> +int tegra_ahb_enable_smmu(void)
>> +{
>> +	return driver_for_each_device(&tegra_ahb_driver.driver, NULL, NULL,
>> +				      __tegra_ahb_enable_smmu);
>> +}
>> +EXPORT_SYMBOL(tegra_ahb_enable_smmu);
>> +#endif
> 
> this is still not correct. If you will always call this whenever you run
> on tegra 3, why do you even expose this function ?

I think the issue is that this function should only be called after the
SMMU driver has initialized the SMMU, and it's ready to be activated.

Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Hiroshi Doyu]

On Wed, 25 Apr 2012 17:51:50 +0200
Stephen Warren <swarren@wwwdotorg.org> wrote:

> On 04/25/2012 05:29 AM, Felipe Balbi wrote:
> > Hi,
> > 
> > On Wed, Apr 25, 2012 at 02:07:37PM +0300, Hiroshi DOYU wrote:
> >> Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> >> ready.
> 
> >> +#ifdef CONFIG_ARCH_TEGRA_3x_SOC
> >> +static int __tegra_ahb_enable_smmu(struct device *dev, void *data)
> >> +{
> >> +	u32 val;
> >> +	struct tegra_ahb *ahb = dev_get_drvdata(dev);
> >> +
> >> +	val = gizmo_readl(ahb, AHB_ARBITRATION_XBAR_CTRL);
> >> +	val |= AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE;
> >> +	gizmo_writel(ahb, val, AHB_ARBITRATION_XBAR_CTRL);
> >> +	return 0;
> >> +}
> >> +
> >> +int tegra_ahb_enable_smmu(void)
> >> +{
> >> +	return driver_for_each_device(&tegra_ahb_driver.driver, NULL, NULL,
> >> +				      __tegra_ahb_enable_smmu);
> >> +}
> >> +EXPORT_SYMBOL(tegra_ahb_enable_smmu);
> >> +#endif
> > 
> > this is still not correct. If you will always call this whenever you run
> > on tegra 3, why do you even expose this function ?
> 
> I think the issue is that this function should only be called after the
> SMMU driver has initialized the SMMU, and it's ready to be activated.

Right. "tegra_ahb_enable_smmu()" is not supposed to be called at
tegra_ahb_probe(), but it is always expected to be called after SMMU
is initialized/gets ready.

The sequence is:
 1, AHB is probed.
 ...<any other operations>...
 2, SMMU is probed.
 ...<any other operations>...
 3, SMMU is ready, then,
 4, SMMU lets AHB know that SMMU is ready to be used by AHB clients.

The above step 4 is "tegra_ahb_enable_smmu()".

Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Stephen Warren]

On 04/25/2012 05:07 AM, Hiroshi DOYU wrote:
> Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> ready.

> +#ifdef CONFIG_ARCH_TEGRA_3x_SOC
> +static int __tegra_ahb_enable_smmu(struct device *dev, void *data)
...
> +int tegra_ahb_enable_smmu(void)
> +{
> +	return driver_for_each_device(&tegra_ahb_driver.driver, NULL, NULL,
> +				      __tegra_ahb_enable_smmu);
> +}
> +EXPORT_SYMBOL(tegra_ahb_enable_smmu);
> +#endif

That looks like a neat solution to avoid having a global device object.

However, if that driver_for_each_device finds no devices, the function
still succeeds. That doesn't seem right, and doesn't allow e.g. the SMMU
to defer its probe until the AHB driver has completed.

Perhaps add a local int variable to tegra_ahb_enable_smmu(), pass the
address to __tegra_ahb_enable_smmu, and have it increment the int. Then,
after calling driver_for_each_device,:

if (!ahb_device_count)
    return -EPROBE_DEFER
if (WARN_ON(ahb_device_count != 1))
    return -EINVAL;
return 0;

Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 1704 bytes --]

Hi,

On Thu, Apr 26, 2012 at 01:55:13PM -0600, Stephen Warren wrote:
> On 04/25/2012 05:07 AM, Hiroshi DOYU wrote:
> > Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> > ready.
> 
> > +#ifdef CONFIG_ARCH_TEGRA_3x_SOC
> > +static int __tegra_ahb_enable_smmu(struct device *dev, void *data)
> ...
> > +int tegra_ahb_enable_smmu(void)
> > +{
> > +	return driver_for_each_device(&tegra_ahb_driver.driver, NULL, NULL,
> > +				      __tegra_ahb_enable_smmu);
> > +}
> > +EXPORT_SYMBOL(tegra_ahb_enable_smmu);
> > +#endif
> 
> That looks like a neat solution to avoid having a global device object.

except that it won't work always. If you happen to have two AHB bridges,
each using a separate smmu but only one smmu is ready, this will set
SMMU_INIT_DONE on both bridges.

> However, if that driver_for_each_device finds no devices, the function
> still succeeds. That doesn't seem right, and doesn't allow e.g. the SMMU
> to defer its probe until the AHB driver has completed.
> 
> Perhaps add a local int variable to tegra_ahb_enable_smmu(), pass the
> address to __tegra_ahb_enable_smmu, and have it increment the int. Then,
> after calling driver_for_each_device,:
> 
> if (!ahb_device_count)
>     return -EPROBE_DEFER
> if (WARN_ON(ahb_device_count != 1))
>     return -EINVAL;
> return 0;

that would look, well, weird. Why don't you just different initcall
leves for this ? Maybe smmu goes into postcore_initcall() and tegra_ahb
goes into postcore_initcall_sync() ?? then you know that SMMU will be
ready by the time you call tegra_ahb probe. Well, unless smmu's probe
fail, but then again, IIUC it won't work anyway...

-- 
balbi

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Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Stephen Warren]

On 04/26/2012 02:26 PM, Felipe Balbi wrote:
> Hi,
> 
> On Thu, Apr 26, 2012 at 01:55:13PM -0600, Stephen Warren wrote:
>> On 04/25/2012 05:07 AM, Hiroshi DOYU wrote:
>>> Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
>>> ready.
>>
>>> +#ifdef CONFIG_ARCH_TEGRA_3x_SOC
>>> +static int __tegra_ahb_enable_smmu(struct device *dev, void *data)
>> ...
>>> +int tegra_ahb_enable_smmu(void)
>>> +{
>>> +	return driver_for_each_device(&tegra_ahb_driver.driver, NULL, NULL,
>>> +				      __tegra_ahb_enable_smmu);
>>> +}
>>> +EXPORT_SYMBOL(tegra_ahb_enable_smmu);
>>> +#endif
>>
>> That looks like a neat solution to avoid having a global device object.
> 
> except that it won't work always. If you happen to have two AHB bridges,
> each using a separate smmu but only one smmu is ready, this will set
> SMMU_INIT_DONE on both bridges.

There is only 1.

>> However, if that driver_for_each_device finds no devices, the function
>> still succeeds. That doesn't seem right, and doesn't allow e.g. the SMMU
>> to defer its probe until the AHB driver has completed.
>>
>> Perhaps add a local int variable to tegra_ahb_enable_smmu(), pass the
>> address to __tegra_ahb_enable_smmu, and have it increment the int. Then,
>> after calling driver_for_each_device,:
>>
>> if (!ahb_device_count)
>>     return -EPROBE_DEFER
>> if (WARN_ON(ahb_device_count != 1))
>>     return -EINVAL;
>> return 0;
> 
> that would look, well, weird. Why don't you just different initcall
> leves for this ? Maybe smmu goes into postcore_initcall() and tegra_ahb
> goes into postcore_initcall_sync() ?? then you know that SMMU will be
> ready by the time you call tegra_ahb probe. Well, unless smmu's probe
> fail, but then again, IIUC it won't work anyway...

Uggh. I'd rather all these devices just got instantiated from device
tree and relied on deferred probe to manage any ordering, rather than
playing complex games with multiple initcall levels (and in the end
probably having to invent more and more initcall levels to correctly
represent all the dependencies).

Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 2792 bytes --]

Hi,

On Thu, Apr 26, 2012 at 02:32:56PM -0600, Stephen Warren wrote:
> On 04/26/2012 02:26 PM, Felipe Balbi wrote:
> > Hi,
> > 
> > On Thu, Apr 26, 2012 at 01:55:13PM -0600, Stephen Warren wrote:
> >> On 04/25/2012 05:07 AM, Hiroshi DOYU wrote:
> >>> Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> >>> ready.
> >>
> >>> +#ifdef CONFIG_ARCH_TEGRA_3x_SOC
> >>> +static int __tegra_ahb_enable_smmu(struct device *dev, void *data)
> >> ...
> >>> +int tegra_ahb_enable_smmu(void)
> >>> +{
> >>> +	return driver_for_each_device(&tegra_ahb_driver.driver, NULL, NULL,
> >>> +				      __tegra_ahb_enable_smmu);
> >>> +}
> >>> +EXPORT_SYMBOL(tegra_ahb_enable_smmu);
> >>> +#endif
> >>
> >> That looks like a neat solution to avoid having a global device object.
> > 
> > except that it won't work always. If you happen to have two AHB bridges,
> > each using a separate smmu but only one smmu is ready, this will set
> > SMMU_INIT_DONE on both bridges.
> 
> There is only 1.

that's why there's a "if you happen to have" statement. If you stick to
this "there is only 1" argument, why do you even make this into a
platform driver ? Just stick the entire code hidden on the
machine_init() code. Drivers a supposed to be able to instantiated
multiple times and always work, this method won't work if tegra99999
ends up with two AHB bridges/SMMUs

> >> However, if that driver_for_each_device finds no devices, the function
> >> still succeeds. That doesn't seem right, and doesn't allow e.g. the SMMU
> >> to defer its probe until the AHB driver has completed.
> >>
> >> Perhaps add a local int variable to tegra_ahb_enable_smmu(), pass the
> >> address to __tegra_ahb_enable_smmu, and have it increment the int. Then,
> >> after calling driver_for_each_device,:
> >>
> >> if (!ahb_device_count)
> >>     return -EPROBE_DEFER
> >> if (WARN_ON(ahb_device_count != 1))
> >>     return -EINVAL;
> >> return 0;
> > 
> > that would look, well, weird. Why don't you just different initcall
> > leves for this ? Maybe smmu goes into postcore_initcall() and tegra_ahb
> > goes into postcore_initcall_sync() ?? then you know that SMMU will be
> > ready by the time you call tegra_ahb probe. Well, unless smmu's probe
> > fail, but then again, IIUC it won't work anyway...
> 
> Uggh. I'd rather all these devices just got instantiated from device
> tree and relied on deferred probe to manage any ordering, rather than
> playing complex games with multiple initcall levels (and in the end
> probably having to invent more and more initcall levels to correctly
> represent all the dependencies).

then do that... it'll be better than current trickery with
driver_for_each_device() and my initcall trickery ;-)

-- 
balbi

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Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Hiroshi Doyu]

From: Felipe Balbi <balbi@ti.com>
Subject: Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB
Date: Thu, 26 Apr 2012 22:38:48 +0200
Message-ID: <20120426203847.GC30690@arwen.pp.htv.fi>

> * PGP Signed by an unknown key
> 
> Hi,
> 
> On Thu, Apr 26, 2012 at 02:32:56PM -0600, Stephen Warren wrote:
> > On 04/26/2012 02:26 PM, Felipe Balbi wrote:
> > > Hi,
> > > 
> > > On Thu, Apr 26, 2012 at 01:55:13PM -0600, Stephen Warren wrote:
> > >> On 04/25/2012 05:07 AM, Hiroshi DOYU wrote:
> > >>> Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> > >>> ready.
> > >>
> > >>> +#ifdef CONFIG_ARCH_TEGRA_3x_SOC
> > >>> +static int __tegra_ahb_enable_smmu(struct device *dev, void *data)
> > >> ...
> > >>> +int tegra_ahb_enable_smmu(void)
> > >>> +{
> > >>> +	return driver_for_each_device(&tegra_ahb_driver.driver, NULL, NULL,
> > >>> +				      __tegra_ahb_enable_smmu);
> > >>> +}
> > >>> +EXPORT_SYMBOL(tegra_ahb_enable_smmu);
> > >>> +#endif
> > >>
> > >> That looks like a neat solution to avoid having a global device object.
> > > 
> > > except that it won't work always. If you happen to have two AHB bridges,
> > > each using a separate smmu but only one smmu is ready, this will set
> > > SMMU_INIT_DONE on both bridges.
> > 
> > There is only 1.
> 
> that's why there's a "if you happen to have" statement. If you stick to
> this "there is only 1" argument, why do you even make this into a
> platform driver ? Just stick the entire code hidden on the
> machine_init() code. Drivers a supposed to be able to instantiated
> multiple times and always work, this method won't work if tegra99999
> ends up with two AHB bridges/SMMUs
> 
> > >> However, if that driver_for_each_device finds no devices, the function
> > >> still succeeds. That doesn't seem right, and doesn't allow e.g. the SMMU
> > >> to defer its probe until the AHB driver has completed.
> > >>
> > >> Perhaps add a local int variable to tegra_ahb_enable_smmu(), pass the
> > >> address to __tegra_ahb_enable_smmu, and have it increment the int. Then,
> > >> after calling driver_for_each_device,:
> > >>
> > >> if (!ahb_device_count)
> > >>     return -EPROBE_DEFER
> > >> if (WARN_ON(ahb_device_count != 1))
> > >>     return -EINVAL;
> > >> return 0;
> > > 
> > > that would look, well, weird. Why don't you just different initcall
> > > leves for this ? Maybe smmu goes into postcore_initcall() and tegra_ahb
> > > goes into postcore_initcall_sync() ?? then you know that SMMU will be
> > > ready by the time you call tegra_ahb probe. Well, unless smmu's probe
> > > fail, but then again, IIUC it won't work anyway...
> > 
> > Uggh. I'd rather all these devices just got instantiated from device
> > tree and relied on deferred probe to manage any ordering, rather than
> > playing complex games with multiple initcall levels (and in the end
> > probably having to invent more and more initcall levels to correctly
> > represent all the dependencies).
> 
> then do that... it'll be better than current trickery with
> driver_for_each_device() and my initcall trickery ;-)

Then, what about something like the following?

 static int tegra_ahb_match_by_smmu(struct device *dev, void *data)
 {
 	struct tegra_ahb *ahb = dev_get_drvdata(dev);
 	struct device_node *dn = data;
 
 	return (ahb->dev->of_node == dn) ? 1 : 0
 }
 
 int tegra_ahb_enable_smmu(struct device_node *ahb)
 {
 	struct device *dev;
 	u32 val;
 
 	dev = driver_find_device(&tegra_ahb_driver.driver, NULL, ahb,
 				 tegra_ahb_match_by_smmu);
 	if (!dev)
 		return -ENODEV;
 
 	val = gizmo_readl(ahb, AHB_ARBITRATION_XBAR_CTRL);
 	val |= AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE;
 	gizmo_writel(ahb, val, AHB_ARBITRATION_XBAR_CTRL);
 	return 0;
 }
 EXPORT_SYMBOL(tegra_ahb_enable_smmu);

	Modified arch/arm/boot/dts/tegra30.dtsi
diff --git a/arch/arm/boot/dts/tegra30.dtsi b/arch/arm/boot/dts/tegra30.dtsi
index 655bc47..28f9138 100644
--- a/arch/arm/boot/dts/tegra30.dtsi
+++ b/arch/arm/boot/dts/tegra30.dtsi
@@ -242,5 +242,6 @@
 	smmu {
 		compatible = "nvidia,tegra30-smmu";
 		mc = <&mc>;
+		ahb = <&ahb>;
 	};
 };

Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Hiroshi Doyu]

From: Hiroshi DOYU <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB
Date: Fri, 27 Apr 2012 09:48:26 +0300 (EEST)
Message-ID: <20120427.094826.1181797260264746303.hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

> From: Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>
> Subject: Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB
> Date: Thu, 26 Apr 2012 22:38:48 +0200
> Message-ID: <20120426203847.GC30690-S8G//mZuvNWo5Im9Ml3/Zg@public.gmane.org>
> 
> > * PGP Signed by an unknown key
> > 
> > Hi,
> > 
> > On Thu, Apr 26, 2012 at 02:32:56PM -0600, Stephen Warren wrote:
> > > On 04/26/2012 02:26 PM, Felipe Balbi wrote:
> > > > Hi,
> > > > 
> > > > On Thu, Apr 26, 2012 at 01:55:13PM -0600, Stephen Warren wrote:
> > > >> On 04/25/2012 05:07 AM, Hiroshi DOYU wrote:
> > > >>> Add extern func, "tegra_ahb_enable_smmu()" to inform AHB that SMMU is
> > > >>> ready.
> > > >>
> > > >>> +#ifdef CONFIG_ARCH_TEGRA_3x_SOC
> > > >>> +static int __tegra_ahb_enable_smmu(struct device *dev, void *data)
> > > >> ...
> > > >>> +int tegra_ahb_enable_smmu(void)
> > > >>> +{
> > > >>> +	return driver_for_each_device(&tegra_ahb_driver.driver, NULL, NULL,
> > > >>> +				      __tegra_ahb_enable_smmu);
> > > >>> +}
> > > >>> +EXPORT_SYMBOL(tegra_ahb_enable_smmu);
> > > >>> +#endif
> > > >>
> > > >> That looks like a neat solution to avoid having a global device object.
> > > > 
> > > > except that it won't work always. If you happen to have two AHB bridges,
> > > > each using a separate smmu but only one smmu is ready, this will set
> > > > SMMU_INIT_DONE on both bridges.
> > > 
> > > There is only 1.
> > 
> > that's why there's a "if you happen to have" statement. If you stick to
> > this "there is only 1" argument, why do you even make this into a
> > platform driver ? Just stick the entire code hidden on the
> > machine_init() code. Drivers a supposed to be able to instantiated
> > multiple times and always work, this method won't work if tegra99999
> > ends up with two AHB bridges/SMMUs
> > 
> > > >> However, if that driver_for_each_device finds no devices, the function
> > > >> still succeeds. That doesn't seem right, and doesn't allow e.g. the SMMU
> > > >> to defer its probe until the AHB driver has completed.
> > > >>
> > > >> Perhaps add a local int variable to tegra_ahb_enable_smmu(), pass the
> > > >> address to __tegra_ahb_enable_smmu, and have it increment the int. Then,
> > > >> after calling driver_for_each_device,:
> > > >>
> > > >> if (!ahb_device_count)
> > > >>     return -EPROBE_DEFER
> > > >> if (WARN_ON(ahb_device_count != 1))
> > > >>     return -EINVAL;
> > > >> return 0;
> > > > 
> > > > that would look, well, weird. Why don't you just different initcall
> > > > leves for this ? Maybe smmu goes into postcore_initcall() and tegra_ahb
> > > > goes into postcore_initcall_sync() ?? then you know that SMMU will be
> > > > ready by the time you call tegra_ahb probe. Well, unless smmu's probe
> > > > fail, but then again, IIUC it won't work anyway...
> > > 
> > > Uggh. I'd rather all these devices just got instantiated from device
> > > tree and relied on deferred probe to manage any ordering, rather than
> > > playing complex games with multiple initcall levels (and in the end
> > > probably having to invent more and more initcall levels to correctly
> > > represent all the dependencies).
> > 
> > then do that... it'll be better than current trickery with
> > driver_for_each_device() and my initcall trickery ;-)
> 
> Then, what about something like the following?
> 
>  static int tegra_ahb_match_by_smmu(struct device *dev, void *data)
>  {
>  	struct tegra_ahb *ahb = dev_get_drvdata(dev);
>  	struct device_node *dn = data;
>  
>  	return (ahb->dev->of_node == dn) ? 1 : 0
>  }
>  
>  int tegra_ahb_enable_smmu(struct device_node *ahb)
>  {
>  	struct device *dev;
>  	u32 val;
>  
>  	dev = driver_find_device(&tegra_ahb_driver.driver, NULL, ahb,
>  				 tegra_ahb_match_by_smmu);
>  	if (!dev)
>  		return -ENODEV;

+		return -EPROBE_DEFER

Maybe this is better(?).

>  
>  	val = gizmo_readl(ahb, AHB_ARBITRATION_XBAR_CTRL);
>  	val |= AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE;
>  	gizmo_writel(ahb, val, AHB_ARBITRATION_XBAR_CTRL);
>  	return 0;
>  }
>  EXPORT_SYMBOL(tegra_ahb_enable_smmu);
> 
> 	Modified arch/arm/boot/dts/tegra30.dtsi
> diff --git a/arch/arm/boot/dts/tegra30.dtsi b/arch/arm/boot/dts/tegra30.dtsi
> index 655bc47..28f9138 100644
> --- a/arch/arm/boot/dts/tegra30.dtsi
> +++ b/arch/arm/boot/dts/tegra30.dtsi
> @@ -242,5 +242,6 @@
>  	smmu {
>  		compatible = "nvidia,tegra30-smmu";
>  		mc = <&mc>;
> +		ahb = <&ahb>;
>  	};
>  };

Re: [PATCHv3 2/4] ARM: tegra: Add SMMU enabler in AHB

[Stephen Warren]

On 04/27/2012 12:48 AM, Hiroshi Doyu wrote:
...
> Then, what about something like the following?
> 
>  static int tegra_ahb_match_by_smmu(struct device *dev, void *data)
>  {
>  	struct tegra_ahb *ahb = dev_get_drvdata(dev);
>  	struct device_node *dn = data;
>  
>  	return (ahb->dev->of_node == dn) ? 1 : 0
>  }

I imagine that function and the driver_find_device() call that uses it
will be pretty common. It may make sense as a drivers/of utility
function, although perhaps we can wait until later to refactor it, once
we actually have multiple pieces of code that do this same thing.

>  int tegra_ahb_enable_smmu(struct device_node *ahb)
>  {
>  	struct device *dev;
>  	u32 val;
>  
>  	dev = driver_find_device(&tegra_ahb_driver.driver, NULL, ahb,
>  				 tegra_ahb_match_by_smmu);
>  	if (!dev)
>  		return -ENODEV;

Yes, -EPROBE_DEFER here as you mentioned in your followup email.

>  
>  	val = gizmo_readl(ahb, AHB_ARBITRATION_XBAR_CTRL);
>  	val |= AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE;
>  	gizmo_writel(ahb, val, AHB_ARBITRATION_XBAR_CTRL);
>  	return 0;
>  }
>  EXPORT_SYMBOL(tegra_ahb_enable_smmu);
> 
> 	Modified arch/arm/boot/dts/tegra30.dtsi
> diff --git a/arch/arm/boot/dts/tegra30.dtsi b/arch/arm/boot/dts/tegra30.dtsi
> index 655bc47..28f9138 100644
> --- a/arch/arm/boot/dts/tegra30.dtsi
> +++ b/arch/arm/boot/dts/tegra30.dtsi
> @@ -242,5 +242,6 @@
>  	smmu {
>  		compatible = "nvidia,tegra30-smmu";
>  		mc = <&mc>;
> +		ahb = <&ahb>;
>  	};
>  };

Yes, that's probably the best (even only) way to connect the two drivers
precisely.