On Tue, Nov 26, 2019 at 05:40:26PM +0100, Christoph Hellwig wrote:

On Tue, Nov 26, 2019 at 12:26:38PM +0100, Christian Zigotzky wrote:

quoted

Hello Christoph,

The PCI TV card works with your patch! I was able to patch your Git kernel 
with the patch above.

I haven't found any error messages in the dmesg yet.

Thanks.  Unfortunately this is a bit of a hack as we need to set
the mask based on runtime information like the magic FSL PCIe window.
Let me try to draft something better up, and thanks already for testing
this one!

Maybe we'll simply force bottom up allocation before calling
swiotlb_init()? Anyway, it's the last memblock allocation.

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 62f74b1b33bd..771e6cf7e2b9 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c

@@ -286,14 +286,15 @@ void __init mem_init(void)
 	/*
 	 * book3s is limited to 16 page sizes due to encoding this in
 	 * a 4-bit field for slices.
 	 */
 	BUILD_BUG_ON(MMU_PAGE_COUNT > 16);
 
 #ifdef CONFIG_SWIOTLB
+	memblock_set_bottom_up(true);
 	swiotlb_init(0);
 #endif
 
 	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
 	set_max_mapnr(max_pfn);
 	memblock_free_all();
 
 

-- 
Sincerely yours,
Mike.