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Message-ID: <8694431d-c669-b7b9-99fa-e99db5d45a7d@xenosoft.de>
Date: Fri, 30 Nov 2018 13:23:20 +0100
From: Christian Zigotzky <chzigotzky@...osoft.de>
To: Christoph Hellwig <hch@....de>
Cc: Michael Ellerman <mpe@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>, linux-arch@...r.kernel.org,
linux-mm@...ck.org, iommu@...ts.linux-foundation.org,
linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
Olof Johansson <olof@...om.net>
Subject: Re: use generic DMA mapping code in powerpc V4
Hi Christoph,
Thanks a lot for your fast reply.
On 30 November 2018 at 11:53AM, Christoph Hellwig wrote:
> Hi Christian,
>
> for such a diverse architecture like powerpc we'll have to rely on
> users / non core developers like you to help with testing.
I see. I will help as good as I can.
>
> Can you try the patch below for he cyrus config?
Yes, of course. I patched your Git kernel and after that I compiled it
again. U-Boot loads the kernel and the dtb file. Then the kernel starts
but it doesn't find any hard disks (partitions).
@All
Could you please also test Christoph's kernel on your PASEMI and NXP
boards? Download: 'git clone git://git.infradead.org/users/hch/misc.git
-b powerpc-dma.4 a'
*PLEASE*
>
> For the nemo one I have no idea yet,
We had some problems with the PASEMI ethernet and DMA two years ago. I
had to deactivate the option PASEMI_IOMMU_DMA_FORCE.
commit 416f37d0816b powerpc/pasemi: Fix coherent_dma_mask for dma engine:
Commit 817820b0 ("powerpc/iommu: Support "hybrid" iommu/direct DMA
ops for coherent_mask < dma_mask) adds a check of coherent_dma_mask for
dma allocations.
Unfortunately current PASemi code does not set this value for the DMA
engine, which ends up with the default value of 0xffffffff, the result
is on a PASemi system with >2Gb ram and iommu enabled the onboard
ethernet stops working due to an inability to allocate memory. Add an
initialisation to pci_dma_dev_setup_pasemi().
Signed-off-by: Darren Stevens <darren@...vens-zone.net>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Links:
https://lists.ozlabs.org/pipermail/linuxppc-dev/2016-July/146701.html
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=416f37d0816b9720b8227953e55954d81456f991
FYI: DMA handling has been rewritten in 2015. We had some problems with
the new DMA code in 2015. I had to revert the commit ' [RFC/PATCH,v2]
powerpc/iommu: Support "hybrid" iommu/direct DMA ops for coherent_mask <
dma_mask' in 2015.
Link: https://patchwork.ozlabs.org/patch/472535/
I had to create a patch in 2015:
diff -rupN linux-4.4/arch/powerpc/Kconfig
linux-4.4-nemo/arch/powerpc/Kconfig
--- linux-4.4/arch/powerpc/Kconfig 2015-12-07 00:43:12.000000000
+0100
+++ linux-4.4-nemo/arch/powerpc/Kconfig 2015-12-07
14:48:23.371987988 +0100
@@ -158,8 +155,6 @@ config PPC
select HAVE_PERF_EVENTS_NMI if PPC64
select EDAC_SUPPORT
select EDAC_ATOMIC_SCRUB
- select ARCH_HAS_DMA_SET_COHERENT_MASK
- select HAVE_ARCH_SECCOMP_FILTER
config GENERIC_CSUM
def_bool CPU_LITTLE_ENDIAN
@@ -419,8 +414,7 @@ config PPC64_SUPPORTS_MEMORY_FAILURE
config KEXEC
bool "kexec system call"
- depends on (PPC_BOOK3S || FSL_BOOKE || (44x && !SMP)) ||
PPC_BOOK3E
- select KEXEC_CORE
+ depends on (PPC_BOOK3S || FSL_BOOKE || (44x && !SMP))
help
kexec is a system call that implements the ability to
shutdown your
current kernel, and to start another kernel. It is like a
reboot
diff -rupN linux-4.4/arch/powerpc/kernel/dma.c
linux-4.4-nemo/arch/powerpc/kernel/dma.c
--- linux-4.4/arch/powerpc/kernel/dma.c 2015-12-07
00:43:12.000000000 +0100
+++ linux-4.4-nemo/arch/powerpc/kernel/dma.c 2015-12-07
14:49:38.098286892 +0100
@@ -40,31 +39,9 @@ static u64 __maybe_unused get_pfn_limit(
return pfn;
}
-static int dma_direct_dma_supported(struct device *dev, u64 mask)
-{
-#ifdef CONFIG_PPC64
- u64 limit = get_dma_offset(dev) + (memblock_end_of_DRAM() - 1);
-
- /* Limit fits in the mask, we are good */
- if (mask >= limit)
- return 1;
-
-#ifdef CONFIG_FSL_SOC
- /* Freescale gets another chance via ZONE_DMA/ZONE_DMA32, however
- * that will have to be refined if/when they support iommus
- */
- return 1;
-#endif
- /* Sorry ... */
- return 0;
-#else
- return 1;
-#endif
-}
-
-void *__dma_direct_alloc_coherent(struct device *dev, size_t size,
- dma_addr_t *dma_handle, gfp_t flag,
- struct dma_attrs *attrs)
+void *dma_direct_alloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flag,
+ struct dma_attrs *attrs)
{
void *ret;
#ifdef CONFIG_NOT_COHERENT_CACHE
@@ -119,9 +96,9 @@ void *__dma_direct_alloc_coherent(struct
#endif
}
-void __dma_direct_free_coherent(struct device *dev, size_t size,
- void *vaddr, dma_addr_t dma_handle,
- struct dma_attrs *attrs)
+void dma_direct_free_coherent(struct device *dev, size_t size,
+ void *vaddr, dma_addr_t dma_handle,
+ struct dma_attrs *attrs)
{
#ifdef CONFIG_NOT_COHERENT_CACHE
__dma_free_coherent(size, vaddr);
@@ -130,51 +107,6 @@ void __dma_direct_free_coherent(struct d
#endif
}
-static void *dma_direct_alloc_coherent(struct device *dev, size_t
size,
- dma_addr_t *dma_handle, gfp_t flag,
- struct dma_attrs *attrs)
-{
- struct iommu_table *iommu;
-
- /* The coherent mask may be smaller than the real mask, check if
- * we can really use the direct ops
- */
- if (dma_direct_dma_supported(dev, dev->coherent_dma_mask))
- return __dma_direct_alloc_coherent(dev, size, dma_handle,
- flag, attrs);
-
- /* Ok we can't ... do we have an iommu ? If not, fail */
- iommu = get_iommu_table_base(dev);
- if (!iommu)
- return NULL;
-
- /* Try to use the iommu */
- return iommu_alloc_coherent(dev, iommu, size, dma_handle,
- dev->coherent_dma_mask, flag,
- dev_to_node(dev));
-}
-
-static void dma_direct_free_coherent(struct device *dev, size_t size,
- void *vaddr, dma_addr_t dma_handle,
- struct dma_attrs *attrs)
-{
- struct iommu_table *iommu;
-
- /* See comments in dma_direct_alloc_coherent() */
- if (dma_direct_dma_supported(dev, dev->coherent_dma_mask))
- return __dma_direct_free_coherent(dev, size, vaddr,
dma_handle,
- attrs);
- /* Maybe we used an iommu ... */
- iommu = get_iommu_table_base(dev);
-
- /* If we hit that we should have never allocated in the first
- * place so how come we are freeing ?
- */
- if (WARN_ON(!iommu))
- return;
- iommu_free_coherent(iommu, size, vaddr, dma_handle);
-}
-
int dma_direct_mmap_coherent(struct device *dev, struct
vm_area_struct *vma,
void *cpu_addr, dma_addr_t handle, size_t size,
struct dma_attrs *attrs)
@@ -215,6 +147,18 @@ static void dma_direct_unmap_sg(struct d
{
}
+static int dma_direct_dma_supported(struct device *dev, u64 mask)
+{
+#ifdef CONFIG_PPC64
+ /* Could be improved so platforms can set the limit in case
+ * they have limited DMA windows
+ */
+ return mask >= get_dma_offset(dev) + (memblock_end_of_DRAM() - 1);
+#else
+ return 1;
+#endif
+}
+
static u64 dma_direct_get_required_mask(struct device *dev)
{
u64 end, mask;
@@ -286,25 +230,6 @@ struct dma_map_ops dma_direct_ops = {
};
EXPORT_SYMBOL(dma_direct_ops);
-int dma_set_coherent_mask(struct device *dev, u64 mask)
-{
- if (!dma_supported(dev, mask)) {
- /*
- * We need to special case the direct DMA ops which can
- * support a fallback for coherent allocations. There
- * is no dma_op->set_coherent_mask() so we have to do
- * things the hard way:
- */
- if (get_dma_ops(dev) != &dma_direct_ops ||
- get_iommu_table_base(dev) == NULL ||
- !dma_iommu_dma_supported(dev, mask))
- return -EIO;
- }
- dev->coherent_dma_mask = mask;
- return 0;
-}
-EXPORT_SYMBOL(dma_set_coherent_mask);
-
#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
int __dma_set_mask(struct device *dev, u64 dma_mask)
Interesting PASEMI ethernet files:
arch/powerpc/platforms/pasemi/iommu.c
drivers/net/ethernet/pasemi/pasemi_mac.c
drivers/net/ethernet/pasemi/pasemi_mac.h
drivers/net/ethernet/pasemi/pasemi_mac_ethtool.c
drivers/net/ethernet/pasemi/Makefile
drivers/net/ethernet/pasemi/Kconfig
I know this is a lot of information but I hope it helps.
Thanks,
Christian
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