Messages in this thread | | | Subject | Re: [PATCH v10 09/23] iommu/io-pgtable-arm-v7s: Extend to support PA[33:32] for MediaTek | From | Robin Murphy <> | Date | Thu, 22 Aug 2019 11:08:58 +0100 |
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On 2019-08-22 9:56 am, Yong Wu wrote: > On Wed, 2019-08-21 at 16:24 +0100, Will Deacon wrote: >> On Wed, Aug 21, 2019 at 09:53:12PM +0800, Yong Wu wrote: >>> MediaTek extend the arm v7s descriptor to support up to 34 bits PA where >>> the bit32 and bit33 are encoded in the bit9 and bit4 of the PTE >>> respectively. Meanwhile the iova still is 32bits. >>> >>> Regarding whether the pagetable address could be over 4GB, the mt8183 >>> support it while the previous mt8173 don't, thus keep it as is. >>> >>> Signed-off-by: Yong Wu <yong.wu@mediatek.com> >>> --- >>> drivers/iommu/io-pgtable-arm-v7s.c | 32 +++++++++++++++++++++++++------- >>> include/linux/io-pgtable.h | 7 +++---- >>> 2 files changed, 28 insertions(+), 11 deletions(-) >> >> [...] >> >>> @@ -731,7 +747,9 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg, >>> { >>> struct arm_v7s_io_pgtable *data; >>> >>> - if (cfg->ias > ARM_V7S_ADDR_BITS || cfg->oas > ARM_V7S_ADDR_BITS) >>> + if (cfg->ias > ARM_V7S_ADDR_BITS || >>> + (cfg->oas > ARM_V7S_ADDR_BITS && >>> + !(cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_EXT))) >> >> Please can you instead change arm_v7s_alloc_pgtable() so that it allows an >> ias of up to 34 when the IO_PGTABLE_QUIRK_ARM_MTK_EXT is set? > > Here I only simply skip the oas checking for our case. then which way do > your prefer? something like you commented before:? > > > if (cfg->ias > ARM_V7S_ADDR_BITS) > return NULL; > > if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_EXT) { > if (!IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT)) > cfg->oas = min(cfg->oas, ARM_V7S_ADDR_BITS); > else if (cfg->oas > 34) > return NULL; > } else if (cfg->oas > ARM_V7S_ADDR_BITS) { > return NULL; > }
All it should take is something like:
if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_EXT) max_oas = 34; else max_oas = 32; if (cfg->oas > max_oas) return NULL;
or even just:
if (cfg->oas > 32 || (cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_EXT && cfg->oas > 34)) return NULL;
(and if we prefer the latter style, perhaps we could introduce some kind of "is_mtk_4gb()" helper to save on verbosity)
We shouldn't need to care about the size of phys_addr_t either way - the fact is that the MTK format can still encode up to 34 bits of PA regardless of whether callers can actually pass addresses that large.
Robin.
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