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caif-hsi: Add RX flip buffer
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Implement RX flip buffer in the cfhsi_rx_done function,
piggy-backed frames is also supported.
This gives a significant performance gain for CAIF over HSI.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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sjur.brandeland@stericsson.com authored and David S. Miller committed Feb 4, 2012
1 parent 576f3cc commit 332ad43
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Showing 2 changed files with 104 additions and 42 deletions.
145 changes: 103 additions & 42 deletions drivers/net/caif/caif_hsi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -426,6 +426,35 @@ static int cfhsi_rx_desc(struct cfhsi_desc *desc, struct cfhsi *cfhsi)
return xfer_sz;
}

static int cfhsi_rx_desc_len(struct cfhsi_desc *desc)
{
int xfer_sz = 0;
int nfrms = 0;
u16 *plen;

if ((desc->header & ~CFHSI_PIGGY_DESC) ||
(desc->offset > CFHSI_MAX_EMB_FRM_SZ)) {

pr_err("Invalid descriptor. %x %x\n", desc->header,
desc->offset);
return -EPROTO;
}

/* Calculate transfer length. */
plen = desc->cffrm_len;
while (nfrms < CFHSI_MAX_PKTS && *plen) {
xfer_sz += *plen;
plen++;
nfrms++;
}

if (xfer_sz % 4) {
pr_err("Invalid payload len: %d, ignored.\n", xfer_sz);
return -EPROTO;
}
return xfer_sz;
}

static int cfhsi_rx_pld(struct cfhsi_desc *desc, struct cfhsi *cfhsi)
{
int rx_sz = 0;
Expand Down Expand Up @@ -517,8 +546,10 @@ static int cfhsi_rx_pld(struct cfhsi_desc *desc, struct cfhsi *cfhsi)
static void cfhsi_rx_done(struct cfhsi *cfhsi)
{
int res;
int desc_pld_len = 0;
int desc_pld_len = 0, rx_len, rx_state;
struct cfhsi_desc *desc = NULL;
u8 *rx_ptr, *rx_buf;
struct cfhsi_desc *piggy_desc = NULL;

desc = (struct cfhsi_desc *)cfhsi->rx_buf;

Expand All @@ -534,65 +565,71 @@ static void cfhsi_rx_done(struct cfhsi *cfhsi)
spin_unlock_bh(&cfhsi->lock);

if (cfhsi->rx_state.state == CFHSI_RX_STATE_DESC) {
desc_pld_len = cfhsi_rx_desc(desc, cfhsi);
if (desc_pld_len == -ENOMEM)
goto restart;
if (desc_pld_len == -EPROTO)
desc_pld_len = cfhsi_rx_desc_len(desc);

if (desc_pld_len < 0)
goto out_of_sync;

rx_buf = cfhsi->rx_buf;
rx_len = desc_pld_len;
if (desc_pld_len > 0 && (desc->header & CFHSI_PIGGY_DESC))
rx_len += CFHSI_DESC_SZ;
if (desc_pld_len == 0)
rx_buf = cfhsi->rx_flip_buf;
} else {
int pld_len;
rx_buf = cfhsi->rx_flip_buf;

if (!cfhsi->rx_state.piggy_desc) {
pld_len = cfhsi_rx_pld(desc, cfhsi);
if (pld_len == -ENOMEM)
goto restart;
if (pld_len == -EPROTO)
goto out_of_sync;
cfhsi->rx_state.pld_len = pld_len;
} else {
pld_len = cfhsi->rx_state.pld_len;
}
rx_len = CFHSI_DESC_SZ;
if (cfhsi->rx_state.pld_len > 0 &&
(desc->header & CFHSI_PIGGY_DESC)) {

if ((pld_len > 0) && (desc->header & CFHSI_PIGGY_DESC)) {
struct cfhsi_desc *piggy_desc;
piggy_desc = (struct cfhsi_desc *)
(desc->emb_frm + CFHSI_MAX_EMB_FRM_SZ +
pld_len);
cfhsi->rx_state.pld_len);

cfhsi->rx_state.piggy_desc = true;

/* Extract piggy-backed descriptor. */
desc_pld_len = cfhsi_rx_desc(piggy_desc, cfhsi);
if (desc_pld_len == -ENOMEM)
goto restart;
/* Extract payload len from piggy-backed descriptor. */
desc_pld_len = cfhsi_rx_desc_len(piggy_desc);
if (desc_pld_len < 0)
goto out_of_sync;

if (desc_pld_len > 0)
rx_len = desc_pld_len;

if (desc_pld_len > 0 &&
(piggy_desc->header & CFHSI_PIGGY_DESC))
rx_len += CFHSI_DESC_SZ;

/*
* Copy needed information from the piggy-backed
* descriptor to the descriptor in the start.
*/
memcpy((u8 *)desc, (u8 *)piggy_desc,
memcpy(rx_buf, (u8 *)piggy_desc,
CFHSI_DESC_SHORT_SZ);

/* Mark no embedded frame here */
piggy_desc->offset = 0;
if (desc_pld_len == -EPROTO)
goto out_of_sync;
}
}

memset(&cfhsi->rx_state, 0, sizeof(cfhsi->rx_state));
if (desc_pld_len) {
cfhsi->rx_state.state = CFHSI_RX_STATE_PAYLOAD;
cfhsi->rx_ptr = cfhsi->rx_buf + CFHSI_DESC_SZ;
cfhsi->rx_len = desc_pld_len;
rx_state = CFHSI_RX_STATE_PAYLOAD;
rx_ptr = rx_buf + CFHSI_DESC_SZ;
} else {
cfhsi->rx_state.state = CFHSI_RX_STATE_DESC;
cfhsi->rx_ptr = cfhsi->rx_buf;
cfhsi->rx_len = CFHSI_DESC_SZ;
rx_state = CFHSI_RX_STATE_DESC;
rx_ptr = rx_buf;
rx_len = CFHSI_DESC_SZ;
}

/* Initiate next read */
if (test_bit(CFHSI_AWAKE, &cfhsi->bits)) {
/* Set up new transfer. */
dev_dbg(&cfhsi->ndev->dev, "%s: Start RX.\n",
__func__);
res = cfhsi->dev->cfhsi_rx(cfhsi->rx_ptr, cfhsi->rx_len,
__func__);

res = cfhsi->dev->cfhsi_rx(rx_ptr, rx_len,
cfhsi->dev);
if (WARN_ON(res < 0)) {
dev_err(&cfhsi->ndev->dev, "%s: RX error %d.\n",
Expand All @@ -601,16 +638,32 @@ static void cfhsi_rx_done(struct cfhsi *cfhsi)
cfhsi->ndev->stats.rx_dropped++;
}
}
return;

restart:
if (++cfhsi->rx_state.retries > CFHSI_MAX_RX_RETRIES) {
dev_err(&cfhsi->ndev->dev, "%s: No memory available "
"in %d iterations.\n",
__func__, CFHSI_MAX_RX_RETRIES);
BUG();
if (cfhsi->rx_state.state == CFHSI_RX_STATE_DESC) {
/* Extract payload from descriptor */
if (cfhsi_rx_desc(desc, cfhsi) < 0)
goto out_of_sync;
} else {
/* Extract payload */
if (cfhsi_rx_pld(desc, cfhsi) < 0)
goto out_of_sync;
if (piggy_desc) {
/* Extract any payload in piggyback descriptor. */
if (cfhsi_rx_desc(piggy_desc, cfhsi) < 0)
goto out_of_sync;
}
}
mod_timer(&cfhsi->rx_slowpath_timer, jiffies + 1);

/* Update state info */
memset(&cfhsi->rx_state, 0, sizeof(cfhsi->rx_state));
cfhsi->rx_state.state = rx_state;
cfhsi->rx_ptr = rx_ptr;
cfhsi->rx_len = rx_len;
cfhsi->rx_state.pld_len = desc_pld_len;
cfhsi->rx_state.piggy_desc = desc->header & CFHSI_PIGGY_DESC;

if (rx_buf != cfhsi->rx_buf)
swap(cfhsi->rx_buf, cfhsi->rx_flip_buf);
return;

out_of_sync:
Expand Down Expand Up @@ -1040,6 +1093,12 @@ int cfhsi_probe(struct platform_device *pdev)
goto err_alloc_rx;
}

cfhsi->rx_flip_buf = kzalloc(CFHSI_BUF_SZ_RX, GFP_KERNEL);
if (!cfhsi->rx_flip_buf) {
res = -ENODEV;
goto err_alloc_rx_flip;
}

/* Pre-calculate inactivity timeout. */
if (inactivity_timeout != -1) {
cfhsi->inactivity_timeout =
Expand Down Expand Up @@ -1138,6 +1197,8 @@ int cfhsi_probe(struct platform_device *pdev)
err_activate:
destroy_workqueue(cfhsi->wq);
err_create_wq:
kfree(cfhsi->rx_flip_buf);
err_alloc_rx_flip:
kfree(cfhsi->rx_buf);
err_alloc_rx:
kfree(cfhsi->tx_buf);
Expand Down
1 change: 1 addition & 0 deletions include/net/caif/caif_hsi.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -138,6 +138,7 @@ struct cfhsi {
u8 *rx_ptr;
u8 *tx_buf;
u8 *rx_buf;
u8 *rx_flip_buf;
spinlock_t lock;
int flow_off_sent;
u32 q_low_mark;
Expand Down

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