wifi: ath11k: fix IOMMU errors on buffer rings

virt_to_phys() doesn't work on systems with IOMMU enabled, which have
non-identity physical-to-IOVA mappings.  It leads to IO_PAGE_FAULTs like this:

[IO_PAGE_FAULT domain=0x0023 address=0x1cce00000 flags=0x0020]

And no association to the AP can be established.

This patch changes that to dma_map_single(), which works correctly. Even
virt_to_phys() documentation says device drivers should not use it:

    This function does not give bus mappings for DMA transfers. In
    almost all conceivable cases a device driver should not be using
    this function

Tested-on: QCN9074 hw1.0 PCI WLAN.HK.2.7.0.1-01744-QCAHKSWPL_SILICONZ-1

Signed-off-by: Zhenghao Gu <imguzh@gmail.com>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20231212031914.47339-1-imguzh@gmail.com

diff --git a/drivers/net/wireless/ath/ath11k/dp.c b/drivers/net/wireless/ath/ath11k/dp.c
index 8975dc57ad77687218c53b602adf7a9f8be677f2..1a62407e5a9f23ec882a5c28c869904a055f8d21 100644 (file)
--- a/drivers/net/wireless/ath/ath11k/dp.c
+++ b/drivers/net/wireless/ath/ath11k/dp.c
@@ -104,11 +104,14 @@ void ath11k_dp_srng_cleanup(struct ath11k_base *ab, struct dp_srng *ring)
        if (!ring->vaddr_unaligned)
                return;
 
-       if (ring->cached)
+       if (ring->cached) {
+               dma_unmap_single(ab->dev, ring->paddr_unaligned, ring->size,
+                                DMA_FROM_DEVICE);
                kfree(ring->vaddr_unaligned);
-       else
+       } else {
                dma_free_coherent(ab->dev, ring->size, ring->vaddr_unaligned,
                                  ring->paddr_unaligned);
+       }
 
        ring->vaddr_unaligned = NULL;
 }
@@ -249,7 +252,18 @@ int ath11k_dp_srng_setup(struct ath11k_base *ab, struct dp_srng *ring,
 
                if (cached) {
                        ring->vaddr_unaligned = kzalloc(ring->size, GFP_KERNEL);
-                       ring->paddr_unaligned = virt_to_phys(ring->vaddr_unaligned);
+                       if (!ring->vaddr_unaligned)
+                               return -ENOMEM;
+
+                       ring->paddr_unaligned = dma_map_single(ab->dev,
+                                                              ring->vaddr_unaligned,
+                                                              ring->size,
+                                                              DMA_FROM_DEVICE);
+                       if (dma_mapping_error(ab->dev, ring->paddr_unaligned)) {
+                               kfree(ring->vaddr_unaligned);
+                               ring->vaddr_unaligned = NULL;
+                               return -ENOMEM;
+                       }
                }
        }
 

diff --git a/drivers/net/wireless/ath/ath11k/hal.c b/drivers/net/wireless/ath/ath11k/hal.c
index c060c4b5c0cc3639745056b58c43a64f16cadf5c..f3d04568c221b6355b0da2f23bb850c9a01732bf 100644 (file)
--- a/drivers/net/wireless/ath/ath11k/hal.c
+++ b/drivers/net/wireless/ath/ath11k/hal.c
@@ -626,15 +626,30 @@ u32 *ath11k_hal_srng_dst_peek(struct ath11k_base *ab, struct hal_srng *srng)
        return NULL;
 }
 
+static u32 *ath11k_hal_srng_dst_peek_with_dma(struct ath11k_base *ab,
+                                             struct hal_srng *srng, dma_addr_t *paddr)
+{
+       lockdep_assert_held(&srng->lock);
+
+       if (srng->u.dst_ring.tp != srng->u.dst_ring.cached_hp) {
+               *paddr = srng->ring_base_paddr +
+                         sizeof(*srng->ring_base_vaddr) * srng->u.dst_ring.tp;
+               return srng->ring_base_vaddr + srng->u.dst_ring.tp;
+       }
+
+       return NULL;
+}
+
 static void ath11k_hal_srng_prefetch_desc(struct ath11k_base *ab,
                                          struct hal_srng *srng)
 {
+       dma_addr_t desc_paddr;
        u32 *desc;
 
        /* prefetch only if desc is available */
-       desc = ath11k_hal_srng_dst_peek(ab, srng);
+       desc = ath11k_hal_srng_dst_peek_with_dma(ab, srng, &desc_paddr);
        if (likely(desc)) {
-               dma_sync_single_for_cpu(ab->dev, virt_to_phys(desc),
+               dma_sync_single_for_cpu(ab->dev, desc_paddr,
                                        (srng->entry_size * sizeof(u32)),
                                        DMA_FROM_DEVICE);
                prefetch(desc);