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net: qrtr: gunyah: Add support for paged skb sends

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Add support to handle paged skbs from the qrtr code layer. Neither the
pskb or the sg APIs support copying into io memory. Add a helper in
qrtr gunyah to copy from scatterlists into the fifo io memory.

Not all skbs coming from qrtr core will be paged skbs, keep support for
linear buffer copies in the tx path.

Change-Id: Ifccab77e45ec70fd4c7bad92b06497c65403461e
Signed-off-by: Chris Lew <quic_clew@quicinc.com>
This commit is contained in:
Chris Lew 2022-05-09 19:45:41 -07:00
parent 164d36655b
commit 9c15def13e
1 changed files with 70 additions and 8 deletions
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78
net/qrtr/gunyah.c
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@ -219,6 +219,60 @@ static void gunyah_tx_write(struct gunyah_pipe *pipe, const void *data,
*pipe->head = cpu_to_le32(head);
}
static size_t gunyah_sg_copy_toio(struct scatterlist *sg, unsigned int nents,
void *buf, size_t buflen, off_t skip)
{
unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_FROM_SG;
struct sg_mapping_iter miter;
unsigned int offset = 0;
sg_miter_start(&miter, sg, nents, sg_flags);
if (!sg_miter_skip(&miter, skip))
return 0;
while ((offset < buflen) && sg_miter_next(&miter)) {
unsigned int len;
len = min(miter.length, buflen - offset);
memcpy_toio(buf + offset, miter.addr, len);
offset += len;
}
sg_miter_stop(&miter);
return offset;
}
static void gunyah_sg_write(struct gunyah_pipe *pipe, struct scatterlist *sg,
int offset, size_t count)
{
size_t len;
u32 head;
int rc = 0;
head = le32_to_cpu(*pipe->head);
len = min_t(size_t, count, pipe->length - head);
if (len) {
rc = gunyah_sg_copy_toio(sg, sg_nents(sg), pipe->fifo + head,
len, offset);
offset += rc;
}
if (len != count)
rc = gunyah_sg_copy_toio(sg, sg_nents(sg), pipe->fifo,
count - len, offset);
head += count;
if (head >= pipe->length)
head -= pipe->length;
smp_wmb();
*pipe->head = cpu_to_le32(head);
}
static void gunyah_set_tx_notify(struct qrtr_gunyah_dev *qdev)
{
*qdev->tx_pipe.read_notify = cpu_to_le32(1);
@ -249,17 +303,10 @@ static int qrtr_gunyah_send(struct qrtr_endpoint *ep, struct sk_buff *skb)
int chunk_size;
int left_size;
int offset;
int rc;
qdev = container_of(ep, struct qrtr_gunyah_dev, ep);
rc = skb_linearize(skb);
if (rc) {
kfree_skb(skb);
return rc;
}
left_size = skb->len;
offset = 0;
while (left_size > 0) {
@ -273,7 +320,22 @@ static int qrtr_gunyah_send(struct qrtr_endpoint *ep, struct sk_buff *skb)
else
chunk_size = left_size;
gunyah_tx_write(&qdev->tx_pipe, skb->data + offset, chunk_size);
if (skb_is_nonlinear(skb)) {
struct scatterlist sg[MAX_SKB_FRAGS + 1];
sg_init_table(sg, skb_shinfo(skb)->nr_frags + 1);
rc = skb_to_sgvec(skb, sg, 0, skb->len);
if (rc < 0) {
pr_err("failed skb_to_sgvec rc:%d\n", rc);
break;
}
gunyah_sg_write(&qdev->tx_pipe, sg, offset,
chunk_size);
} else {
gunyah_tx_write(&qdev->tx_pipe, skb->data + offset,
chunk_size);
}
offset += chunk_size;
left_size -= chunk_size;