On Mon, 2012-07-09 at 23:28 +0800, Hiroshi Doyu wrote: > Hi Mark, adding linux-tegra on Cc:.... > > Mark Zhang <[email protected]> wrote @ Mon, 9 Jul 2012 14:13:13 +0200: > > > > Hi Mark, Cc: Thierry & Ken, > > > > > > Can GEM allow DRM to use contigious memory? That could be easier. > > > > > > Otherwise, I think that you need to make drv->dev iommu'able before > > > calling DMA API if you want to use IOMMU. To make drv->dev iommu'able, > > > you need to call arm_iommu_create_mapping() and arm_iommu_attach_device(). > > > > Thank you. Yes, we need to call these functions otherwise iommu will not be > > enabled at all. > > So my question is: > > 1. in arm_iommu_create_mapping, we need to specify the base address > > of the iova. Is these an API which can get this base address? I > > mean, SMMU serves a lot of clients and maybe every client will > > specify a range of iova which it needs. So as the center point of > > these clients, does SMMU module has a function which can be used by > > client to get this base address? > > The SMMU patch was sent but it depends on the following framework. > > [PATCH 0/5] IOMMU: Make IOMMU-API ready for GART-like hardware > https://lkml.org/lkml/2012/1/19/170 >
Got it. Seems this patch hasn't been integrated yet. Besides, SMMU module should do some implementations for this set/get attribute functions as well, right? > > 2. I took a quick glance of tegra-smmu.c, I noticed that there is a > > dts property named dma-window, which it's value is: <0x0 > > 0x40000000>. Does this means the iova which SMMU handles is from 0 - > > 1G? IIRC, SMMU handles 4G address space... > > It tries to avoid overwrapping 1-1 iovirt-phys mapping, which is > necessary for some drivers right now. > Sorry I didn't get it. What is overwrapping 1-1 iovirt-phys mapping? > > 3. Right now in my drm driver, arm_iommu_attach_device failed with > > an error code: -22(Invalid Argument). I think this is caused by > > these codes in function smmu_iommu_attach_dev: > > > > map = (unsigned long)dev->platform_data; > > if (!map) > > return -EINVAL; > > > > So, does this mean the drm_device should have a "platform_data"(right now > > it is NULL so -EINVAL returned)? > > I skimmed the codes of tegra-smmu.c, seems this "platform_data" has > > specific usage and should be composed in some rules. > > Could you explain a little bit about this? > > You can skip that check with the following patch. > Yes, it works. Right now the framebuffer works on my T30. Thank you! > From 42a03ff88ed133db613389d2cc4c4ad33cd5d7e3 Mon Sep 17 00:00:00 2001 > From: Hiroshi DOYU <[email protected]> > Date: Tue, 28 Feb 2012 15:33:17 +0200 > Subject: [PATCH 1/1] iommu/tegra: smmu: Enable all SWGRP by default > > This should be revisited along with successors, which would > introduce different configurations. > > Signed-off-by: Hiroshi DOYU <[email protected]> > --- > drivers/iommu/tegra-smmu.c | 12 ++++++++++++ > 1 files changed, 12 insertions(+), 0 deletions(-) > > diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c > index bf33c03..3bc5c91 100644 > --- a/drivers/iommu/tegra-smmu.c > +++ b/drivers/iommu/tegra-smmu.c > @@ -38,6 +38,8 @@ > #include <mach/smmu.h> > #include <mach/tegra_smmu.h> > > +#define SKIP_SWGRP_CHECK /* FIXME: SWGRP should be passed from DT. */ > + > /* bitmap of the page sizes currently supported */ > #define SMMU_IOMMU_PGSIZES (SZ_4K) > > @@ -316,11 +318,15 @@ static int __smmu_client_set_hwgrp(struct smmu_client > *c, > offs = HWGRP_ASID_REG(i); > val = smmu_read(smmu, offs); > if (on) { > +#if !defined(SKIP_SWGRP_CHECK) > if (WARN_ON(val & mask)) > goto err_hw_busy; > +#endif > val |= mask; > } else { > +#if !defined(SKIP_SWGRP_CHECK) > WARN_ON((val & mask) == mask); > +#endif > val &= ~mask; > } > smmu_write(smmu, val, offs); > @@ -701,9 +707,15 @@ static int smmu_iommu_attach_dev(struct iommu_domain > *domain, > return -ENOMEM; > client->dev = dev; > client->as = as; > + > +#ifdef SKIP_SWGRP_CHECK > + /* Enable all SWGRP blindly by default */ > + map = (1 << HWGRP_COUNT) - 1; > +#else > map = (unsigned long)dev->platform_data; > if (!map) > return -EINVAL; > +#endif > > err = smmu_client_enable_hwgrp(client, map); > if (err) -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
