diff mbox series

[v3,2/9] gpu: host1x: Add context bus

Message ID 20220218113952.3077606-3-mperttunen@nvidia.com (mailing list archive)
State New, archived
Headers show
Series Host1x context isolation support | expand

Commit Message

Mikko Perttunen Feb. 18, 2022, 11:39 a.m. UTC 
The context bus is a "dummy" bus that contains struct devices that
correspond to IOMMU contexts assigned through Host1x to processes.

Even when host1x itself is built as a module, the bus is registered
in built-in code so that the built-in ARM SMMU driver is able to
reference it.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
---
 drivers/gpu/Makefile               |  3 +--
 drivers/gpu/host1x/Kconfig         |  5 +++++
 drivers/gpu/host1x/Makefile        |  1 +
 drivers/gpu/host1x/context_bus.c   | 31 ++++++++++++++++++++++++++++++
 include/linux/host1x_context_bus.h | 15 +++++++++++++++
 5 files changed, 53 insertions(+), 2 deletions(-)
 create mode 100644 drivers/gpu/host1x/context_bus.c
 create mode 100644 include/linux/host1x_context_bus.h

Comments

Dmitry Osipenko Feb. 19, 2022, 5:54 p.m. UTC | #1 
18.02.2022 14:39, Mikko Perttunen пишет:
> +config TEGRA_HOST1X_CONTEXT_BUS
> +	bool
> +
>  config TEGRA_HOST1X
>  	tristate "NVIDIA Tegra host1x driver"
>  	depends on ARCH_TEGRA || (ARM && COMPILE_TEST)
>  	select DMA_SHARED_BUFFER
> +	select TEGRA_HOST1X_CONTEXT_BUS

What is the point of TEGRA_HOST1X_CONTEXT_BUS if it's selected
unconditionally?
Dmitry Osipenko Feb. 19, 2022, 6:15 p.m. UTC | #2 
19.02.2022 20:54, Dmitry Osipenko пишет:
> 18.02.2022 14:39, Mikko Perttunen пишет:
>> +config TEGRA_HOST1X_CONTEXT_BUS
>> +	bool
>> +
>>  config TEGRA_HOST1X
>>  	tristate "NVIDIA Tegra host1x driver"
>>  	depends on ARCH_TEGRA || (ARM && COMPILE_TEST)
>>  	select DMA_SHARED_BUFFER
>> +	select TEGRA_HOST1X_CONTEXT_BUS
> 
> What is the point of TEGRA_HOST1X_CONTEXT_BUS if it's selected
> unconditionally?

I see now that it's used by arm-smmu.c, should be okay then.
Robin Murphy Feb. 22, 2022, 9:30 p.m. UTC | #3 
On 2022-02-22 16:21, Christoph Hellwig wrote:
> On Fri, Feb 18, 2022 at 01:39:45PM +0200, Mikko Perttunen wrote:
>> The context bus is a "dummy" bus that contains struct devices that
>> correspond to IOMMU contexts assigned through Host1x to processes.
>>
>> Even when host1x itself is built as a module, the bus is registered
>> in built-in code so that the built-in ARM SMMU driver is able to
>> reference it.
>>
>> Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
>> ---
>>   drivers/gpu/Makefile               |  3 +--
>>   drivers/gpu/host1x/Kconfig         |  5 +++++
>>   drivers/gpu/host1x/Makefile        |  1 +
>>   drivers/gpu/host1x/context_bus.c   | 31 ++++++++++++++++++++++++++++++
>>   include/linux/host1x_context_bus.h | 15 +++++++++++++++
>>   5 files changed, 53 insertions(+), 2 deletions(-)
>>   create mode 100644 drivers/gpu/host1x/context_bus.c
>>   create mode 100644 include/linux/host1x_context_bus.h
>>
>> diff --git a/drivers/gpu/Makefile b/drivers/gpu/Makefile
>> index 835c88318cec..8997f0096545 100644
>> --- a/drivers/gpu/Makefile
>> +++ b/drivers/gpu/Makefile
>> @@ -2,7 +2,6 @@
>>   # drm/tegra depends on host1x, so if both drivers are built-in care must be
>>   # taken to initialize them in the correct order. Link order is the only way
>>   # to ensure this currently.
>> -obj-$(CONFIG_TEGRA_HOST1X)	+= host1x/
>> -obj-y			+= drm/ vga/
>> +obj-y			+= host1x/ drm/ vga/
>>   obj-$(CONFIG_IMX_IPUV3_CORE)	+= ipu-v3/
>>   obj-$(CONFIG_TRACE_GPU_MEM)		+= trace/
>> diff --git a/drivers/gpu/host1x/Kconfig b/drivers/gpu/host1x/Kconfig
>> index 6815b4db17c1..1861a8180d3f 100644
>> --- a/drivers/gpu/host1x/Kconfig
>> +++ b/drivers/gpu/host1x/Kconfig
>> @@ -1,8 +1,13 @@
>>   # SPDX-License-Identifier: GPL-2.0-only
>> +
>> +config TEGRA_HOST1X_CONTEXT_BUS
>> +	bool
>> +
>>   config TEGRA_HOST1X
>>   	tristate "NVIDIA Tegra host1x driver"
>>   	depends on ARCH_TEGRA || (ARM && COMPILE_TEST)
>>   	select DMA_SHARED_BUFFER
>> +	select TEGRA_HOST1X_CONTEXT_BUS
>>   	select IOMMU_IOVA
>>   	help
>>   	  Driver for the NVIDIA Tegra host1x hardware.
>> diff --git a/drivers/gpu/host1x/Makefile b/drivers/gpu/host1x/Makefile
>> index d2b6f7de0498..c891a3e33844 100644
>> --- a/drivers/gpu/host1x/Makefile
>> +++ b/drivers/gpu/host1x/Makefile
>> @@ -18,3 +18,4 @@ host1x-y = \
>>   	hw/host1x07.o
>>   
>>   obj-$(CONFIG_TEGRA_HOST1X) += host1x.o
>> +obj-$(CONFIG_TEGRA_HOST1X_CONTEXT_BUS) += context_bus.o
>> diff --git a/drivers/gpu/host1x/context_bus.c b/drivers/gpu/host1x/context_bus.c
>> new file mode 100644
>> index 000000000000..2625914f3c7d
>> --- /dev/null
>> +++ b/drivers/gpu/host1x/context_bus.c
>> @@ -0,0 +1,31 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (c) 2021, NVIDIA Corporation.
>> + */
>> +
>> +#include <linux/device.h>
>> +#include <linux/of.h>
>> +
>> +struct bus_type host1x_context_device_bus_type = {
>> +	.name = "host1x-context",
>> +};
>> +EXPORT_SYMBOL(host1x_context_device_bus_type);
> 
> EXPORT_SYMBOL_GPL, please.
> 
> But the pattern that this copies in arm_smmu_bus_init is really
> ugly.  I think we need to figure out a way todo that without having
> to export all the low-level bus types.

Yup, as it happens that was the first step on my mission :)

https://gitlab.arm.com/linux-arm/linux-rm/-/commits/iommu/bus

Still a way to go with the main meat of that work, though, so I was 
figuring this could probably land as-is and I'll sweep it up in due course.

Robin.
diff mbox series

Patch

diff --git a/drivers/gpu/Makefile b/drivers/gpu/Makefile
index 835c88318cec..8997f0096545 100644
--- a/drivers/gpu/Makefile
+++ b/drivers/gpu/Makefile
@@ -2,7 +2,6 @@ 
 # drm/tegra depends on host1x, so if both drivers are built-in care must be
 # taken to initialize them in the correct order. Link order is the only way
 # to ensure this currently.
-obj-$(CONFIG_TEGRA_HOST1X)	+= host1x/
-obj-y			+= drm/ vga/
+obj-y			+= host1x/ drm/ vga/
 obj-$(CONFIG_IMX_IPUV3_CORE)	+= ipu-v3/
 obj-$(CONFIG_TRACE_GPU_MEM)		+= trace/
diff --git a/drivers/gpu/host1x/Kconfig b/drivers/gpu/host1x/Kconfig
index 6815b4db17c1..1861a8180d3f 100644
--- a/drivers/gpu/host1x/Kconfig
+++ b/drivers/gpu/host1x/Kconfig
@@ -1,8 +1,13 @@ 
 # SPDX-License-Identifier: GPL-2.0-only
+
+config TEGRA_HOST1X_CONTEXT_BUS
+	bool
+
 config TEGRA_HOST1X
 	tristate "NVIDIA Tegra host1x driver"
 	depends on ARCH_TEGRA || (ARM && COMPILE_TEST)
 	select DMA_SHARED_BUFFER
+	select TEGRA_HOST1X_CONTEXT_BUS
 	select IOMMU_IOVA
 	help
 	  Driver for the NVIDIA Tegra host1x hardware.
diff --git a/drivers/gpu/host1x/Makefile b/drivers/gpu/host1x/Makefile
index d2b6f7de0498..c891a3e33844 100644
--- a/drivers/gpu/host1x/Makefile
+++ b/drivers/gpu/host1x/Makefile
@@ -18,3 +18,4 @@  host1x-y = \
 	hw/host1x07.o
 
 obj-$(CONFIG_TEGRA_HOST1X) += host1x.o
+obj-$(CONFIG_TEGRA_HOST1X_CONTEXT_BUS) += context_bus.o
diff --git a/drivers/gpu/host1x/context_bus.c b/drivers/gpu/host1x/context_bus.c
new file mode 100644
index 000000000000..2625914f3c7d
--- /dev/null
+++ b/drivers/gpu/host1x/context_bus.c
@@ -0,0 +1,31 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021, NVIDIA Corporation.
+ */
+
+#include <linux/device.h>
+#include <linux/of.h>
+
+struct bus_type host1x_context_device_bus_type = {
+	.name = "host1x-context",
+};
+EXPORT_SYMBOL(host1x_context_device_bus_type);
+
+static int __init host1x_context_device_bus_init(void)
+{
+	int err;
+
+	if (!of_machine_is_compatible("nvidia,tegra186") &&
+	    !of_machine_is_compatible("nvidia,tegra194") &&
+	    !of_machine_is_compatible("nvidia,tegra234"))
+		return 0;
+
+	err = bus_register(&host1x_context_device_bus_type);
+	if (err < 0) {
+		pr_err("bus type registration failed: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+postcore_initcall(host1x_context_device_bus_init);
diff --git a/include/linux/host1x_context_bus.h b/include/linux/host1x_context_bus.h
new file mode 100644
index 000000000000..72462737a6db
--- /dev/null
+++ b/include/linux/host1x_context_bus.h
@@ -0,0 +1,15 @@ 
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2021, NVIDIA Corporation. All rights reserved.
+ */
+
+#ifndef __LINUX_HOST1X_CONTEXT_BUS_H
+#define __LINUX_HOST1X_CONTEXT_BUS_H
+
+#include <linux/device.h>
+
+#ifdef CONFIG_TEGRA_HOST1X_CONTEXT_BUS
+extern struct bus_type host1x_context_device_bus_type;
+#endif
+
+#endif