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

[Marek Szyprowski <m.szyprowski@samsung.com>]

Hi Subash,

On Thursday, April 12, 2012 11:06 AM Subash Patel wrote:

> 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.

Right, I simplified the code too much. Keeping these definitions inside machine 
files was a better idea. I completely forgot that Exynos sub-platform now covers
both Exynos4 and Exynos5 SoC families.

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center