wil6210: Introduce struct for sw context

Enable adding more data to the SW context.
For now, add flag "mapped_as_page", to separate decisions on free-ing skb
and type of DMA mapping.
This allows linking skb itself to any descriptor of fragmented skb.

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 44 insertions, 28 deletions

diff --git a/drivers/net/wireless/ath/wil6210/debugfs.c b/drivers/net/wireless/ath/wil6210/debugfs.c
index e8308ec30970..971ce46a6b5f 100644
--- a/drivers/net/wireless/ath/wil6210/debugfs.c
+++ b/drivers/net/wireless/ath/wil6210/debugfs.c
@@ -51,7 +51,7 @@ static void wil_print_vring(struct seq_file *s, struct wil6210_priv *wil,
                         if ((i % 64) == 0 && (i != 0))
                                 seq_printf(s, "\n");
                         seq_printf(s, "%s", (d->dma.status & BIT(0)) ?
-                                        "S" : (vring->ctx[i] ? "H" : "h"));
+                                        "S" : (vring->ctx[i].skb ? "H" : "h"));
                 }
                 seq_printf(s, "\n");
         }
@@ -406,7 +406,7 @@ static int wil_txdesc_debugfs_show(struct seq_file *s, void *data)
                 volatile struct vring_tx_desc *d =
                                 &(vring->va[dbg_txdesc_index].tx);
                 volatile u32 *u = (volatile u32 *)d;
-                struct sk_buff *skb = vring->ctx[dbg_txdesc_index];
+                struct sk_buff *skb = vring->ctx[dbg_txdesc_index].skb;
 
                 seq_printf(s, "Tx[%3d] = {\n", dbg_txdesc_index);
                 seq_printf(s, "  MAC = 0x%08x 0x%08x 0x%08x 0x%08x\n",
diff --git a/drivers/net/wireless/ath/wil6210/txrx.c b/drivers/net/wireless/ath/wil6210/txrx.c
index dd5f35eb64b4..44cdd2a3dff3 100644
--- a/drivers/net/wireless/ath/wil6210/txrx.c
+++ b/drivers/net/wireless/ath/wil6210/txrx.c
@@ -70,7 +70,7 @@ static int wil_vring_alloc(struct wil6210_priv *wil, struct vring *vring)
 
         vring->swhead = 0;
         vring->swtail = 0;
-        vring->ctx = kzalloc(vring->size * sizeof(vring->ctx[0]), GFP_KERNEL);
+        vring->ctx = kcalloc(vring->size, sizeof(vring->ctx[0]), GFP_KERNEL);
         if (!vring->ctx) {
                 vring->va = NULL;
                 return -ENOMEM;
@@ -108,39 +108,39 @@ static void wil_vring_free(struct wil6210_priv *wil, struct vring *vring,
 
         while (!wil_vring_is_empty(vring)) {
                 dma_addr_t pa;
-                struct sk_buff *skb;
                 u16 dmalen;
+                struct wil_ctx *ctx;
 
                 if (tx) {
                         struct vring_tx_desc dd, *d = ⅆ
                         volatile struct vring_tx_desc *_d =
                                         &vring->va[vring->swtail].tx;
 
+                        ctx = &vring->ctx[vring->swtail];
                         *d = *_d;
                         pa = wil_desc_addr(&d->dma.addr);
                         dmalen = le16_to_cpu(d->dma.length);
-                        skb = vring->ctx[vring->swtail];
-                        if (skb) {
-                                dma_unmap_single(dev, pa, dmalen,
-                                                 DMA_TO_DEVICE);
-                                dev_kfree_skb_any(skb);
-                                vring->ctx[vring->swtail] = NULL;
-                        } else {
+                        if (vring->ctx[vring->swtail].mapped_as_page) {
                                 dma_unmap_page(dev, pa, dmalen,
                                                DMA_TO_DEVICE);
+                        } else {
+                                dma_unmap_single(dev, pa, dmalen,
+                                                 DMA_TO_DEVICE);
                         }
+                        if (ctx->skb)
+                                dev_kfree_skb_any(ctx->skb);
                         vring->swtail = wil_vring_next_tail(vring);
                 } else { /* rx */
                         struct vring_rx_desc dd, *d = ⅆ
                         volatile struct vring_rx_desc *_d =
                                         &vring->va[vring->swhead].rx;
 
+                        ctx = &vring->ctx[vring->swhead];
                         *d = *_d;
                         pa = wil_desc_addr(&d->dma.addr);
                         dmalen = le16_to_cpu(d->dma.length);
-                        skb = vring->ctx[vring->swhead];
                         dma_unmap_single(dev, pa, dmalen, DMA_FROM_DEVICE);
-                        kfree_skb(skb);
+                        kfree_skb(ctx->skb);
                         wil_vring_advance_head(vring, 1);
                 }
         }
@@ -187,7 +187,7 @@ static int wil_vring_alloc_skb(struct wil6210_priv *wil, struct vring *vring,
         d->dma.status = 0; /* BIT(0) should be 0 for HW_OWNED */
         d->dma.length = cpu_to_le16(sz);
         *_d = *d;
-        vring->ctx[i] = skb;
+        vring->ctx[i].skb = skb;
 
         return 0;
 }
@@ -352,11 +352,11 @@ static struct sk_buff *wil_vring_reap_rx(struct wil6210_priv *wil,
                 return NULL;
         }
 
-        skb = vring->ctx[vring->swhead];
+        skb = vring->ctx[vring->swhead].skb;
         d = wil_skb_rxdesc(skb);
         *d = *_d;
         pa = wil_desc_addr(&d->dma.addr);
-        vring->ctx[vring->swhead] = NULL;
+        vring->ctx[vring->swhead].skb = NULL;
         wil_vring_advance_head(vring, 1);
 
         dma_unmap_single(dev, pa, sz, DMA_FROM_DEVICE);
@@ -703,7 +703,7 @@ static int wil_tx_vring(struct wil6210_priv *wil, struct vring *vring,
                 if (unlikely(dma_mapping_error(dev, pa)))
                         goto dma_error;
                 wil_tx_desc_map(d, pa, len, vring_index);
-                vring->ctx[i] = NULL;
+                vring->ctx[i].mapped_as_page = 1;
                 *_d = *d;
         }
         /* for the last seg only */
@@ -724,7 +724,7 @@ static int wil_tx_vring(struct wil6210_priv *wil, struct vring *vring,
          * to prevent skb release before accounting
          * in case of immediate "tx done"
          */
-        vring->ctx[i] = skb_get(skb);
+        vring->ctx[i].skb = skb_get(skb);
 
         return 0;
  dma_error:
@@ -732,6 +732,7 @@ static int wil_tx_vring(struct wil6210_priv *wil, struct vring *vring,
         /* Note: increment @f to operate with positive index */
         for (f++; f > 0; f--) {
                 u16 dmalen;
+                struct wil_ctx *ctx = &vring->ctx[i];
 
                 i = (swhead + f) % vring->size;
                 _d = &(vring->va[i].tx);
@@ -739,10 +740,15 @@ static int wil_tx_vring(struct wil6210_priv *wil, struct vring *vring,
                 _d->dma.status = TX_DMA_STATUS_DU;
                 pa = wil_desc_addr(&d->dma.addr);
                 dmalen = le16_to_cpu(d->dma.length);
-                if (vring->ctx[i])
-                        dma_unmap_single(dev, pa, dmalen, DMA_TO_DEVICE);
-                else
+                if (ctx->mapped_as_page)
                         dma_unmap_page(dev, pa, dmalen, DMA_TO_DEVICE);
+                else
+                        dma_unmap_single(dev, pa, dmalen, DMA_TO_DEVICE);
+
+                if (ctx->skb)
+                        dev_kfree_skb_any(ctx->skb);
+
+                memset(ctx, 0, sizeof(*ctx));
         }
 
         return -EINVAL;
@@ -821,8 +827,9 @@ int wil_tx_complete(struct wil6210_priv *wil, int ringid)
                                               &vring->va[vring->swtail].tx;
                 struct vring_tx_desc dd, *d = ⅆ
                 dma_addr_t pa;
-                struct sk_buff *skb;
                 u16 dmalen;
+                struct wil_ctx *ctx = &vring->ctx[vring->swtail];
+                struct sk_buff *skb = ctx->skb;
 
                 *d = *_d;
 
@@ -840,7 +847,11 @@ int wil_tx_complete(struct wil6210_priv *wil, int ringid)
                                   (const void *)d, sizeof(*d), false);
 
                 pa = wil_desc_addr(&d->dma.addr);
-                skb = vring->ctx[vring->swtail];
+                if (ctx->mapped_as_page)
+                        dma_unmap_page(dev, pa, dmalen, DMA_TO_DEVICE);
+                else
+                        dma_unmap_single(dev, pa, dmalen, DMA_TO_DEVICE);
+
                 if (skb) {
                         if (d->dma.error == 0) {
                                 ndev->stats.tx_packets++;
@@ -849,12 +860,9 @@ int wil_tx_complete(struct wil6210_priv *wil, int ringid)
                                 ndev->stats.tx_errors++;
                         }
 
-                        dma_unmap_single(dev, pa, dmalen, DMA_TO_DEVICE);
                         dev_kfree_skb_any(skb);
-                        vring->ctx[vring->swtail] = NULL;
-                } else {
-                        dma_unmap_page(dev, pa, dmalen, DMA_TO_DEVICE);
                 }
+                memset(ctx, 0, sizeof(*ctx));
                 /*
                  * There is no need to touch HW descriptor:
                  * - ststus bit TX_DMA_STATUS_DU is set by design,
diff --git a/drivers/net/wireless/ath/wil6210/wil6210.h b/drivers/net/wireless/ath/wil6210/wil6210.h
index 129c480c8a20..c4a51638736a 100644
--- a/drivers/net/wireless/ath/wil6210/wil6210.h
+++ b/drivers/net/wireless/ath/wil6210/wil6210.h
@@ -183,6 +183,14 @@ struct pending_wmi_event {
         } __packed event;
 };
 
+/**
+ * struct wil_ctx - software context for Vring descriptor
+ */
+struct wil_ctx {
+        struct sk_buff *skb;
+        u8 mapped_as_page:1;
+};
+
 union vring_desc;
 
 struct vring {
@@ -192,7 +200,7 @@ struct vring {
         u32 swtail;
         u32 swhead;
         u32 hwtail; /* write here to inform hw */
-        void **ctx; /* void *ctx[size] - software context */
+        struct wil_ctx *ctx; /* ctx[size] - software context */
 };
 
 enum { /* for wil6210_priv.status */