Re: [PATCH] ARM: Exynos4: integrate SYSMMU driver with DMA-mapping interface

[Subash Patel <subashrp@gmail.com>]

Hello Marek,

On 04/11/2012 08:06 PM, Marek Szyprowski wrote:
> This patch provides an provides setup code which assigns IOMMU controllers
> to FIMC and MFC devices and enables IOMMU aware DMA-mapping for them.
> It has been tested on Samsung Exynos4 platform, NURI board.
>
> Most of the work is done in the s5p_sysmmu_late_init() function, which
> first assigns SYSMMU controller to respective client device and then
> creates IO address space mapping structures. In this example 128 MiB of
> address space is created at 0x20000000 for most of the devices. IO address
> allocation precision is set to 2^4 pages, so all small allocations will be
> aligned to 64 pages. This reduces the size of the io address space bitmap
> to 4 KiB.
>
> To solve the clock dependency issues, parent clocks have been added to each
> SYSMMU controller bus clock. This models the true hardware behavior,
> because client's device bus clock also gates the respective sysmmu bus
> clock.
>
> Signed-off-by: Marek Szyprowski<m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park<kyungmin.park@samsung.com>
> ---
>   arch/arm/mach-exynos/Kconfig               |    1 +
>   arch/arm/mach-exynos/clock-exynos4.c       |   64 +++++++++++++++-------------
>   arch/arm/mach-exynos/dev-sysmmu.c          |   44 +++++++++++++++++++
>   arch/arm/mach-exynos/include/mach/sysmmu.h |    3 +
>   drivers/iommu/Kconfig                      |    1 +
>   5 files changed, 84 insertions(+), 29 deletions(-)
>
> diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
> index 801c738..25b9ba5 100644
> --- a/arch/arm/mach-exynos/Kconfig
> +++ b/arch/arm/mach-exynos/Kconfig
> @@ -288,6 +288,7 @@ config MACH_NURI
>   	select S5P_DEV_USB_EHCI
>   	select S5P_SETUP_MIPIPHY
>   	select EXYNOS4_DEV_DMA
> +	select EXYNOS_DEV_SYSMMU
>   	select EXYNOS4_SETUP_FIMC
>   	select EXYNOS4_SETUP_FIMD0
>   	select EXYNOS4_SETUP_I2C1
> diff --git a/arch/arm/mach-exynos/clock-exynos4.c b/arch/arm/mach-exynos/clock-exynos4.c
> index 29ae4df..fe459a3 100644
> --- a/arch/arm/mach-exynos/clock-exynos4.c
> +++ b/arch/arm/mach-exynos/clock-exynos4.c
> @@ -497,29 +497,6 @@ static struct clk *exynos4_gate_clocks[] = {
>
>   static struct clk exynos4_init_clocks_off[] = {
>   	{
> -		.name		= "timers",
> -		.parent		=&exynos4_clk_aclk_100.clk,
> -		.enable		= exynos4_clk_ip_peril_ctrl,
> -		.ctrlbit	= (1<<24),
> -	}, {
> -		.name		= "csis",
> -		.devname	= "s5p-mipi-csis.0",
> -		.enable		= exynos4_clk_ip_cam_ctrl,
> -		.ctrlbit	= (1<<  4),
> -		.parent		=&exynos4_clk_gate_cam,
> -	}, {
> -		.name		= "csis",
> -		.devname	= "s5p-mipi-csis.1",
> -		.enable		= exynos4_clk_ip_cam_ctrl,
> -		.ctrlbit	= (1<<  5),
> -		.parent		=&exynos4_clk_gate_cam,
> -	}, {
> -		.name		= "jpeg",
> -		.id		= 0,
> -		.enable		= exynos4_clk_ip_cam_ctrl,
> -		.ctrlbit	= (1<<  6),
> -		.parent		=&exynos4_clk_gate_cam,
> -	}, {
>   		.name		= "fimc",
>   		.devname	= "exynos4-fimc.0",
>   		.enable		= exynos4_clk_ip_cam_ctrl,
> @@ -544,6 +521,35 @@ static struct clk exynos4_init_clocks_off[] = {
>   		.ctrlbit	= (1<<  3),
>   		.parent		=&exynos4_clk_gate_cam,
>   	}, {
> +		.name		= "mfc",
> +		.devname	= "s5p-mfc",
> +		.enable		= exynos4_clk_ip_mfc_ctrl,
> +		.ctrlbit	= (1<<  0),
> +		.parent		=&exynos4_clk_gate_mfc,
> +	}, {
> +		.name		= "timers",
> +		.parent		=&exynos4_clk_aclk_100.clk,
> +		.enable		= exynos4_clk_ip_peril_ctrl,
> +		.ctrlbit	= (1<<24),
> +	}, {
> +		.name		= "csis",
> +		.devname	= "s5p-mipi-csis.0",
> +		.enable		= exynos4_clk_ip_cam_ctrl,
> +		.ctrlbit	= (1<<  4),
> +		.parent		=&exynos4_clk_gate_cam,
> +	}, {
> +		.name		= "csis",
> +		.devname	= "s5p-mipi-csis.1",
> +		.enable		= exynos4_clk_ip_cam_ctrl,
> +		.ctrlbit	= (1<<  5),
> +		.parent		=&exynos4_clk_gate_cam,
> +	}, {
> +		.name		= "jpeg",
> +		.id		= 0,
> +		.enable		= exynos4_clk_ip_cam_ctrl,
> +		.ctrlbit	= (1<<  6),
> +		.parent		=&exynos4_clk_gate_cam,
> +	}, {
>   		.name		= "hsmmc",
>   		.devname	= "exynos4-sdhci.0",
>   		.parent		=&exynos4_clk_aclk_133.clk,
> @@ -674,12 +680,6 @@ static struct clk exynos4_init_clocks_off[] = {
>   		.ctrlbit	= (1<<  0),
>   		.parent		=&exynos4_clk_gate_lcd0,
>   	}, {
> -		.name		= "mfc",
> -		.devname	= "s5p-mfc",
> -		.enable		= exynos4_clk_ip_mfc_ctrl,
> -		.ctrlbit	= (1<<  0),
> -		.parent		=&exynos4_clk_gate_mfc,
> -	}, {
>   		.name		= "i2c",
>   		.devname	= "s3c2440-i2c.0",
>   		.parent		=&exynos4_clk_aclk_100.clk,
> @@ -738,11 +738,13 @@ static struct clk exynos4_init_clocks_off[] = {
>   		.devname	= SYSMMU_CLOCK_DEVNAME(mfc_l, 0),
>   		.enable		= exynos4_clk_ip_mfc_ctrl,
>   		.ctrlbit	= (1<<  1),
> +		.parent		=&exynos4_init_clocks_off[4],
>   	}, {
>   		.name		= SYSMMU_CLOCK_NAME,
>   		.devname	= SYSMMU_CLOCK_DEVNAME(mfc_r, 1),
>   		.enable		= exynos4_clk_ip_mfc_ctrl,
>   		.ctrlbit	= (1<<  2),
> +		.parent		=&exynos4_init_clocks_off[4],
>   	}, {
>   		.name		= SYSMMU_CLOCK_NAME,
>   		.devname	= SYSMMU_CLOCK_DEVNAME(tv, 2),
> @@ -763,21 +765,25 @@ static struct clk exynos4_init_clocks_off[] = {
>   		.devname	= SYSMMU_CLOCK_DEVNAME(fimc0, 5),
>   		.enable		= exynos4_clk_ip_cam_ctrl,
>   		.ctrlbit	= (1<<  7),
> +		.parent		=&exynos4_init_clocks_off[0],
>   	}, {
>   		.name		= SYSMMU_CLOCK_NAME,
>   		.devname	= SYSMMU_CLOCK_DEVNAME(fimc1, 6),
>   		.enable		= exynos4_clk_ip_cam_ctrl,
>   		.ctrlbit	= (1<<  8),
> +		.parent		=&exynos4_init_clocks_off[1],
>   	}, {
>   		.name		= SYSMMU_CLOCK_NAME,
>   		.devname	= SYSMMU_CLOCK_DEVNAME(fimc2, 7),
>   		.enable		= exynos4_clk_ip_cam_ctrl,
>   		.ctrlbit	= (1<<  9),
> +		.parent		=&exynos4_init_clocks_off[2],
>   	}, {
>   		.name		= SYSMMU_CLOCK_NAME,
>   		.devname	= SYSMMU_CLOCK_DEVNAME(fimc3, 8),
>   		.enable		= exynos4_clk_ip_cam_ctrl,
>   		.ctrlbit	= (1<<  10),
> +		.parent		=&exynos4_init_clocks_off[3],
>   	}, {
>   		.name		= SYSMMU_CLOCK_NAME,
>   		.devname	= SYSMMU_CLOCK_DEVNAME(fimd0, 10),
> diff --git a/arch/arm/mach-exynos/dev-sysmmu.c b/arch/arm/mach-exynos/dev-sysmmu.c
> index 3544638..31f2d6ca 100644
> --- a/arch/arm/mach-exynos/dev-sysmmu.c
> +++ b/arch/arm/mach-exynos/dev-sysmmu.c
> @@ -12,12 +12,15 @@
>
>   #include<linux/platform_device.h>
>   #include<linux/dma-mapping.h>
> +#include<linux/slab.h>
>
>   #include<plat/cpu.h>
> +#include<plat/devs.h>
>
>   #include<mach/map.h>
>   #include<mach/irqs.h>
>   #include<mach/sysmmu.h>
> +#include<asm/dma-iommu.h>
>
>   static u64 exynos_sysmmu_dma_mask = DMA_BIT_MASK(32);
>
> @@ -276,3 +279,44 @@ static int __init init_sysmmu_platform_device(void)
>    * see pm_domain.c, which use arch_initcall()
>    */
>   core_initcall(init_sysmmu_platform_device);
> +#ifdef CONFIG_ARM_DMA_USE_IOMMU
> +int __init s5p_create_iommu_mapping(struct device *client, dma_addr_t base,
> +				    unsigned int size, int order)
> +{
> +	struct dma_iommu_mapping *mapping;
> +	if (!client)
> +		return 0;
> +	mapping = arm_iommu_create_mapping(&platform_bus_type, base, size, order);
> +	if (!mapping)
> +		return -ENOMEM;
> +	client->dma_parms = kzalloc(sizeof(*client->dma_parms), GFP_KERNEL);
> +	dma_set_max_seg_size(client, 0xffffffffu);
> +	arm_iommu_attach_device(client, mapping);
> +	return 0;
> +}
> +
> +/*
> + * s5p_sysmmu_late_init
> + * Create DMA-mapping IOMMU context for specified devices. This function must
> + * be called later, once SYSMMU driver gets registered and probed.
> + */
> +static int __init s5p_sysmmu_late_init(void)
> +{
> +	platform_set_sysmmu(&SYSMMU_PLATDEV(fimc0).dev,&s5p_device_fimc0.dev);
> +	platform_set_sysmmu(&SYSMMU_PLATDEV(fimc1).dev,&s5p_device_fimc1.dev);
> +	platform_set_sysmmu(&SYSMMU_PLATDEV(fimc2).dev,&s5p_device_fimc2.dev);
> +	platform_set_sysmmu(&SYSMMU_PLATDEV(fimc3).dev,&s5p_device_fimc3.dev);
> +	platform_set_sysmmu(&SYSMMU_PLATDEV(mfc_l).dev,&s5p_device_mfc_l.dev);
> +	platform_set_sysmmu(&SYSMMU_PLATDEV(mfc_r).dev,&s5p_device_mfc_r.dev);
> +
> +	s5p_create_iommu_mapping(&s5p_device_fimc0.dev, 0x20000000, SZ_128M, 4);
> +	s5p_create_iommu_mapping(&s5p_device_fimc1.dev, 0x20000000, SZ_128M, 4);
> +	s5p_create_iommu_mapping(&s5p_device_fimc2.dev, 0x20000000, SZ_128M, 4);
> +	s5p_create_iommu_mapping(&s5p_device_fimc3.dev, 0x20000000, SZ_128M, 4);
> +	s5p_create_iommu_mapping(&s5p_device_mfc_l.dev, 0x20000000, SZ_128M, 4);
> +	s5p_create_iommu_mapping(&s5p_device_mfc_r.dev, 0x40000000, SZ_128M, 4);
> +
> +	return 0;
> +}
> +device_initcall(s5p_sysmmu_late_init);

Shouldn't these things be specific to a SoC? With this RFC, it happens 
that you will predefine the IOMMU attachment and mapping information for 
devices in common location (dev-sysmmu.c)? This may lead to problems 
because there are some IP's with SYSMMU support in exynos5, but not 
available in exynos4 (eg: GSC, FIMC-LITE, FIMC-ISP) Previously we used 
to do above declaration in individual machine file, which I think was 
more meaningful.

> +#endif
> diff --git a/arch/arm/mach-exynos/include/mach/sysmmu.h b/arch/arm/mach-exynos/include/mach/sysmmu.h
> index 998daf2..07cae3a 100644
> --- a/arch/arm/mach-exynos/include/mach/sysmmu.h
> +++ b/arch/arm/mach-exynos/include/mach/sysmmu.h
> @@ -57,6 +57,9 @@ static inline void platform_set_sysmmu(
>   }
>   #endif
>
> +int __init s5p_create_iommu_mapping(struct device *client, dma_addr_t base,
> +				    unsigned int size, int order);
> +
>   #else /* !CONFIG_EXYNOS_DEV_SYSMMU */
>   #define platform_set_sysmmu(dev, sysmmu) do { } while (0)
>   #endif
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index 3b745bb..223e31e 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -166,6 +166,7 @@ config EXYNOS_IOMMU
>   	bool "Exynos IOMMU Support"
>   	depends on EXYNOS_DEV_SYSMMU
>   	select IOMMU_API
> +	select ARM_DMA_USE_IOMMU
>   	help
>   	  Support for the IOMMU(System MMU) of Samsung Exynos application
>   	  processor family. This enables H/W multimedia accellerators to see
Regards,
Subash

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