[PATCH kernel v2] powerps/pseries/dma: Add support for 2M IOMMU page size
From: Alexey Kardashevskiy <hidden>
Date: 2021-10-06 04:48:18
The upcoming PAPR spec adds a 2M page size, bit 23 right after 16G page size in the "ibm,query-pe-dma-window" call. This adds support for the new page size. Since the new page size is out of sorted order, this changes the loop to not assume that shift[] is sorted. This has now been tested and is known to work on a pre-release version of phyp. Reviewed-by: Leonardo Bras <redacted> Reviewed-by: Frederic Barrat <redacted> Signed-off-by: Alexey Kardashevskiy <redacted> --- Changes: v2: * adjusted the commit log about testing --- arch/powerpc/platforms/pseries/iommu.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index dab5c56ffd0e..269f61d519c2 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c@@ -1159,14 +1159,15 @@ static void reset_dma_window(struct pci_dev *dev, struct device_node *par_dn) /* Return largest page shift based on "IO Page Sizes" output of ibm,query-pe-dma-window. */ static int iommu_get_page_shift(u32 query_page_size) { - /* Supported IO page-sizes according to LoPAR */ + /* Supported IO page-sizes according to LoPAR, note that 2M is out of order */ const int shift[] = { __builtin_ctzll(SZ_4K), __builtin_ctzll(SZ_64K), __builtin_ctzll(SZ_16M), __builtin_ctzll(SZ_32M), __builtin_ctzll(SZ_64M), __builtin_ctzll(SZ_128M), - __builtin_ctzll(SZ_256M), __builtin_ctzll(SZ_16G) + __builtin_ctzll(SZ_256M), __builtin_ctzll(SZ_16G), __builtin_ctzll(SZ_2M) }; int i = ARRAY_SIZE(shift) - 1; + int ret = 0; /* * On LoPAR, ibm,query-pe-dma-window outputs "IO Page Sizes" using a bit field:
@@ -1176,11 +1177,10 @@ static int iommu_get_page_shift(u32 query_page_size) */ for (; i >= 0 ; i--) { if (query_page_size & (1 << i)) - return shift[i]; + ret = max(ret, shift[i]); } - /* No valid page size found. */ - return 0; + return ret; } static struct property *ddw_property_create(const char *propname, u32 liobn, u64 dma_addr,
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2.30.2