net: ieee802154: adf7242: Rework IRQ and packet handling

 * Stop unconditionally polling for RC_STATUS_PHY_RDY at the entry of
the threaded IRQ handler. Once IRQ_RX_PKT_RCVD is received we can
read immediately the packet from the buffer. However we still need
to wait afterwards for RC_STATUS_PHY_RDY, to make sure that the
ACK (in case requested) was processed and send out by the
Radio Controller, before we issue the next CMD_RC_RX.
This significantly reduces the overall time spend in the threaded
IRQ handler.

 * Avoid raise condition between xmit and coincident packet reception,
by disabling the IRQ and clearing the IRQ status upon xmit entry.

 * Introduce helper functions adf7242_clear_irqstat() and adf7242_cmd_rx()

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Stefan Schmidt <stefan@osg.samsung.com>

1 files changed, 39 insertions, 15 deletions

diff --git a/drivers/net/ieee802154/adf7242.c b/drivers/net/ieee802154/adf7242.c
index 548bec16906e..64f1b1e77bc0 100644
--- a/drivers/net/ieee802154/adf7242.c
+++ b/drivers/net/ieee802154/adf7242.c
@@ -563,6 +563,22 @@ static int adf7242_verify_firmware(struct adf7242_local *lp,
         return 0;
 }
 
+static void adf7242_clear_irqstat(struct adf7242_local *lp)
+{
+        adf7242_write_reg(lp, REG_IRQ1_SRC1, IRQ_CCA_COMPLETE | IRQ_SFD_RX |
+                          IRQ_SFD_TX | IRQ_RX_PKT_RCVD | IRQ_TX_PKT_SENT |
+                          IRQ_FRAME_VALID | IRQ_ADDRESS_VALID | IRQ_CSMA_CA);
+}
+
+static int adf7242_cmd_rx(struct adf7242_local *lp)
+{
+        /* Wait until the ACK is sent */
+        adf7242_wait_status(lp, RC_STATUS_PHY_RDY, RC_STATUS_MASK, __LINE__);
+        adf7242_clear_irqstat(lp);
+
+        return adf7242_cmd(lp, CMD_RC_RX);
+}
+
 static int adf7242_set_txpower(struct ieee802154_hw *hw, int mbm)
 {
         struct adf7242_local *lp = hw->priv;
@@ -666,7 +682,7 @@ static int adf7242_start(struct ieee802154_hw *hw)
         struct adf7242_local *lp = hw->priv;
 
         adf7242_cmd(lp, CMD_RC_PHY_RDY);
-        adf7242_write_reg(lp, REG_IRQ1_SRC1, 0xFF);
+        adf7242_clear_irqstat(lp);
         enable_irq(lp->spi->irq);
         set_bit(FLAG_START, &lp->flags);
 
@@ -677,10 +693,10 @@ static void adf7242_stop(struct ieee802154_hw *hw)
 {
         struct adf7242_local *lp = hw->priv;
 
+        disable_irq(lp->spi->irq);
         adf7242_cmd(lp, CMD_RC_IDLE);
         clear_bit(FLAG_START, &lp->flags);
-        disable_irq(lp->spi->irq);
-        adf7242_write_reg(lp, REG_IRQ1_SRC1, 0xFF);
+        adf7242_clear_irqstat(lp);
 }
 
 static int adf7242_channel(struct ieee802154_hw *hw, u8 page, u8 channel)
@@ -795,9 +811,12 @@ static int adf7242_xmit(struct ieee802154_hw *hw, struct sk_buff *skb)
         struct adf7242_local *lp = hw->priv;
         int ret;
 
+        /* ensure existing instances of the IRQ handler have completed */
+        disable_irq(lp->spi->irq);
         set_bit(FLAG_XMIT, &lp->flags);
         reinit_completion(&lp->tx_complete);
         adf7242_cmd(lp, CMD_RC_PHY_RDY);
+        adf7242_clear_irqstat(lp);
 
         ret = adf7242_write_fbuf(lp, skb->data, skb->len);
         if (ret)
@@ -806,6 +825,7 @@ static int adf7242_xmit(struct ieee802154_hw *hw, struct sk_buff *skb)
         ret = adf7242_cmd(lp, CMD_RC_CSMACA);
         if (ret)
                 goto err;
+        enable_irq(lp->spi->irq);
 
         ret = wait_for_completion_interruptible_timeout(&lp->tx_complete,
                                                         HZ / 10);
@@ -828,7 +848,7 @@ static int adf7242_xmit(struct ieee802154_hw *hw, struct sk_buff *skb)
 
 err:
         clear_bit(FLAG_XMIT, &lp->flags);
-        adf7242_cmd(lp, CMD_RC_RX);
+        adf7242_cmd_rx(lp);
 
         return ret;
 }
@@ -852,7 +872,7 @@ static int adf7242_rx(struct adf7242_local *lp)
 
         skb = dev_alloc_skb(len);
         if (!skb) {
-                adf7242_cmd(lp, CMD_RC_RX);
+                adf7242_cmd_rx(lp);
                 return -ENOMEM;
         }
 
@@ -860,14 +880,14 @@ static int adf7242_rx(struct adf7242_local *lp)
         ret = adf7242_read_fbuf(lp, data, len, true);
         if (ret < 0) {
                 kfree_skb(skb);
-                adf7242_cmd(lp, CMD_RC_RX);
+                adf7242_cmd_rx(lp);
                 return ret;
         }
 
         lqi = data[len - 2];
         lp->rssi = data[len - 1];
 
-        adf7242_cmd(lp, CMD_RC_RX);
+        ret = adf7242_cmd_rx(lp);
 
         skb_trim(skb, len - 2); /* Don't put RSSI/LQI or CRC into the frame */
 
@@ -876,7 +896,7 @@ static int adf7242_rx(struct adf7242_local *lp)
         dev_dbg(&lp->spi->dev, "%s: ret=%d len=%d lqi=%d rssi=%d\n",
                 __func__, ret, (int)len, (int)lqi, lp->rssi);
 
-        return 0;
+        return ret;
 }
 
 static const struct ieee802154_ops adf7242_ops = {
@@ -932,10 +952,7 @@ static irqreturn_t adf7242_isr(int irq, void *data)
         unsigned int xmit;
         u8 irq1;
 
-        adf7242_wait_status(lp, RC_STATUS_PHY_RDY, RC_STATUS_MASK, __LINE__);
-
         adf7242_read_reg(lp, REG_IRQ1_SRC1, &irq1);
-        adf7242_write_reg(lp, REG_IRQ1_SRC1, irq1);
 
         if (!(irq1 & (IRQ_RX_PKT_RCVD | IRQ_CSMA_CA)))
                 dev_err(&lp->spi->dev, "%s :ERROR IRQ1 = 0x%X\n",
@@ -946,6 +963,9 @@ static irqreturn_t adf7242_isr(int irq, void *data)
         xmit = test_bit(FLAG_XMIT, &lp->flags);
 
         if (xmit && (irq1 & IRQ_CSMA_CA)) {
+                adf7242_wait_status(lp, RC_STATUS_PHY_RDY,
+                                    RC_STATUS_MASK, __LINE__);
+
                 if (ADF7242_REPORT_CSMA_CA_STAT) {
                         u8 astat;
 
@@ -966,6 +986,7 @@ static irqreturn_t adf7242_isr(int irq, void *data)
                         lp->tx_stat = SUCCESS;
                 }
                 complete(&lp->tx_complete);
+                adf7242_clear_irqstat(lp);
         } else if (!xmit && (irq1 & IRQ_RX_PKT_RCVD) &&
                    (irq1 & IRQ_FRAME_VALID)) {
                 adf7242_rx(lp);
@@ -974,16 +995,19 @@ static irqreturn_t adf7242_isr(int irq, void *data)
                 dev_dbg(&lp->spi->dev, "%s:%d : ERROR IRQ1 = 0x%X\n",
                         __func__, __LINE__, irq1);
                 adf7242_cmd(lp, CMD_RC_PHY_RDY);
-                adf7242_write_reg(lp, REG_IRQ1_SRC1, 0xFF);
-                adf7242_cmd(lp, CMD_RC_RX);
+                adf7242_cmd_rx(lp);
         } else {
                 /* This can only be xmit without IRQ, likely a RX packet.
                  * we get an TX IRQ shortly - do nothing or let the xmit
                  * timeout handle this
                  */
+
                 dev_dbg(&lp->spi->dev, "%s:%d : ERROR IRQ1 = 0x%X, xmit %d\n",
                         __func__, __LINE__, irq1, xmit);
+                adf7242_wait_status(lp, RC_STATUS_PHY_RDY,
+                                    RC_STATUS_MASK, __LINE__);
                 complete(&lp->tx_complete);
+                adf7242_clear_irqstat(lp);
         }
 
         return IRQ_HANDLED;
@@ -1003,7 +1027,7 @@ static int adf7242_soft_reset(struct adf7242_local *lp, int line)
         adf7242_set_promiscuous_mode(lp->hw, lp->promiscuous);
         adf7242_set_csma_params(lp->hw, lp->min_be, lp->max_be,
                                 lp->max_cca_retries);
-        adf7242_write_reg(lp, REG_IRQ1_SRC1, 0xFF);
+        adf7242_clear_irqstat(lp);
 
         if (test_bit(FLAG_START, &lp->flags)) {
                 enable_irq(lp->spi->irq);
@@ -1069,7 +1093,7 @@ static int adf7242_hw_init(struct adf7242_local *lp)
         adf7242_write_reg(lp, REG_IRQ1_EN0, 0);
         adf7242_write_reg(lp, REG_IRQ1_EN1, IRQ_RX_PKT_RCVD | IRQ_CSMA_CA);
 
-        adf7242_write_reg(lp, REG_IRQ1_SRC1, 0xFF);
+        adf7242_clear_irqstat(lp);
         adf7242_write_reg(lp, REG_IRQ1_SRC0, 0xFF);
 
         adf7242_cmd(lp, CMD_RC_IDLE);