[PATCH 3/7] iommu/omap: Convert to devicetree
Anna, Suman
s-anna at ti.com
Mon Dec 23 14:48:36 EST 2013
Hi Florian,
On 12/17/2013 06:53 AM, Florian Vaussard wrote:
> As OMAP2+ is moving to a full DT boot for 3.14, commit 7ce93f3
> "ARM: OMAP2+: Fix more missing data for omap3.dtsi file" adds
> basic DT bits. But the driver is not yet converted, so this will
> not work and driver will not be probed. Convert it!
>
> Apart from standard bindings, this patch uses 'dma-window' (already
> used by Tegra SMMU) and adds a custom 'ti,#tlb-entries' binding.
>
> Signed-off-by: Florian Vaussard <florian.vaussard at epfl.ch>
> ---
> .../devicetree/bindings/iommu/ti,omap-iommu.txt | 19 ++++++++++++
> arch/arm/mach-omap2/omap-iommu.c | 5 +++
> drivers/iommu/omap-iommu.c | 36 +++++++++++++++++++---
> 3 files changed, 55 insertions(+), 5 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/iommu/ti,omap-iommu.txt
>
> diff --git a/Documentation/devicetree/bindings/iommu/ti,omap-iommu.txt b/Documentation/devicetree/bindings/iommu/ti,omap-iommu.txt
> new file mode 100644
> index 0000000..4e5027c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iommu/ti,omap-iommu.txt
> @@ -0,0 +1,19 @@
> +OMAP3 IOMMU used by camera subsystem
As I mentioned in comments on your cover-letter, the current binding is
only limited to OMAP3 ISP, but the driver is common for all OMAP2+ SoCs.
This binding an update to handle all SoCs.
To summarize the differences, OMAP2/3 has the same MMU register set for
all remote processor MMUs (IVA/DSP/ISP) with the only difference being
the number of TLBs supported (8 for ISP on OMAP2/3 and 32 for all other
instances on all OMAP2+ SoCs). Depending on whether the compatibility
property is defined for an SoC or for the processor, "ti,#tlb-entries"
can be retrieved directly from the match data or made as an optional
property, with the default value being 32.
OMAP4 and OMAP5 have some additional registers (MMU_FAULT_PC,
MMU_FAULT_STATUS, MMU_GP_REG/DSPSS_MMU_GPR) on top of the OMAP2/OMAP3
ones, and DRA7 a further superset of OMAP4/OMAP5. The only difference is
the definition of the MMU_GPR register, which is different between the
IPU and DSP processors, but present at the same offset, and dictates the
validity of the MMU_FAULT_PC and MMU_FAULT_STATUS registers. The MMU_GPR
register is also not defined on OMAP4430 ES1.0, but is present on all
other newer SoCs.
> +
> +Required properties:
> +- compatible : "ti,omap3-mmu-isp"
My suggestion would be to use
"ti,omap2-iommu" for OMAP2/OMAP3 MMUs with the optional
"ti,#tlb-entries" to distinguish ISP MMU.
"ti,omap4-iommu" for OMAP4/OMAP5 MMUs with an additional boolean
property to distinguish the presence/functionality of the MMU_GPR register
"ti,dra7-iommu" for DRA7 MMUs
Mark, Tony,
Do you have any other recommendations given the above summary?
> +- ti,hwmods : "mmu_isp"
Replace with general description
> +- reg : address space for the configuration registers
> +- interrupts : interrupt line
> +- dma-window : IOVA start address and length.
> +- ti,#tlb-entries : number of entries in the translation look-aside buffer
> +
> +Example:
> + mmu_isp: mmu_isp at 480bd400 {
> + compatible = "ti,omap3-mmu-isp";
> + ti,hwmods = "mmu_isp";
> + reg = <0x480bd400 0x80>;
> + interrupts = <8>;
> + dma-window = <0 0xfffff000>;
> + ti,#tlb-entries = <8>;
> + };
> diff --git a/arch/arm/mach-omap2/omap-iommu.c b/arch/arm/mach-omap2/omap-iommu.c
> index f6daae8..f1fab56 100644
> --- a/arch/arm/mach-omap2/omap-iommu.c
> +++ b/arch/arm/mach-omap2/omap-iommu.c
> @@ -10,6 +10,7 @@
> * published by the Free Software Foundation.
> */
>
> +#include <linux/of.h>
> #include <linux/module.h>
> #include <linux/platform_device.h>
> #include <linux/err.h>
> @@ -58,6 +59,10 @@ static int __init omap_iommu_dev_init(struct omap_hwmod *oh, void *unused)
>
> static int __init omap_iommu_init(void)
> {
> + /* If dtb is there, the devices will be created dynamically */
> + if (of_have_populated_dt())
> + return -ENODEV;
> +
> return omap_hwmod_for_each_by_class("mmu", omap_iommu_dev_init, NULL);
> }
> /* must be ready before omap3isp is probed */
> diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
> index 385bf5e..51efcc4 100644
> --- a/drivers/iommu/omap-iommu.c
> +++ b/drivers/iommu/omap-iommu.c
> @@ -23,6 +23,9 @@
> #include <linux/spinlock.h>
> #include <linux/io.h>
> #include <linux/pm_runtime.h>
> +#include <linux/of.h>
> +#include <linux/of_iommu.h>
> +#include <linux/of_irq.h>
>
> #include <asm/cacheflush.h>
>
> @@ -1171,20 +1174,30 @@ static int omap_iommu_probe(struct platform_device *pdev)
> {
> int err = -ENODEV;
> int irq;
> + size_t len;
> struct omap_iommu *obj;
> struct resource *res;
> struct iommu_platform_data *pdata = pdev->dev.platform_data;
> + struct device_node *of = pdev->dev.of_node;
>
> obj = kzalloc(sizeof(*obj) + MMU_REG_SIZE, GFP_KERNEL);
> if (!obj)
> return -ENOMEM;
>
> - obj->nr_tlb_entries = pdata->nr_tlb_entries;
> - obj->name = pdata->name;
> + if (of) {
> + obj->name = of->name;
> + of_property_read_u32(of, "ti,#tlb-entries",
> + &obj->nr_tlb_entries);
> + of_get_dma_window(of, NULL, 0, NULL, &obj->da_start, &len);
There is no error checking performed on both the of functions.
> + obj->da_end = obj->da_start + len;
> + } else {
> + obj->nr_tlb_entries = pdata->nr_tlb_entries;
> + obj->name = pdata->name;
> + obj->da_start = pdata->da_start;
> + obj->da_end = pdata->da_end;
> + }
> obj->dev = &pdev->dev;
> obj->ctx = (void *)obj + sizeof(*obj);
> - obj->da_start = pdata->da_start;
> - obj->da_end = pdata->da_end;
>
> spin_lock_init(&obj->iommu_lock);
> mutex_init(&obj->mmap_lock);
> @@ -1210,7 +1223,11 @@ static int omap_iommu_probe(struct platform_device *pdev)
> goto err_ioremap;
> }
>
> - irq = platform_get_irq(pdev, 0);
> + if (of)
> + irq = irq_of_parse_and_map(of, 0);
> + else
> + irq = platform_get_irq(pdev, 0);
The platform_get_irq should still work just fine, so this change can
probably be left out. We can switch once the driver supports DT-only
devices completely.
regards
Suman
> +
> if (irq < 0) {
> err = -ENODEV;
> goto err_irq;
> @@ -1260,11 +1277,20 @@ static int omap_iommu_remove(struct platform_device *pdev)
> return 0;
> }
>
> +#if defined(CONFIG_OF)
> +static struct of_device_id omap_iommu_of_match[] = {
> + { .compatible = "ti,omap3-mmu-isp" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, omap_iommu_of_match);
> +#endif
> +
> static struct platform_driver omap_iommu_driver = {
> .probe = omap_iommu_probe,
> .remove = omap_iommu_remove,
> .driver = {
> .name = "omap-iommu",
> + .of_match_table = omap_iommu_of_match,
> },
> };
>
>
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