This patch adds a handling for calibration if we are 5 minutes in PLL
state. I first tried to implement the calibration functionality in
TX_ON state via register values CF_START and DCU_START, but this occurs
a one second delay at each calibration time.
An another solution to start a calibration is to switch from TRX_OFF
state into TX_ON, then a calibration is done automatically by
transceiver. This method will be used in this patch, after each transmit
of a frame we check with jiffies if the PLL is set 5 minutes without
doing a TRX_OFF->(TX_ON || RX_AACK_ON) or channel switch. The worst case
would be a transceiver in receiving mode only, but this is under normal
operation very unlikely.
Signed-off-by: Alexander Aring <alex.aring@xxxxxxxxx>
Cc: Phoebe Buckheister <phoebe.buckheister@xxxxxxxxxxxxxxxxxx>
Cc: Werner Almesberger <werner@xxxxxxxxxxxxxxx>
---
drivers/net/ieee802154/at86rf230.c | 72 ++++++++++++++++++++++++++++++--------
1 file changed, 58 insertions(+), 14 deletions(-)
diff --git a/drivers/net/ieee802154/at86rf230.c b/drivers/net/ieee802154/at86rf230.c
index cdcd152..3b81c62 100644
--- a/drivers/net/ieee802154/at86rf230.c
+++ b/drivers/net/ieee802154/at86rf230.c
@@ -20,6 +20,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/hrtimer.h>
+#include <linux/jiffies.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/gpio.h>
@@ -60,6 +61,8 @@ struct at86rf2xx_chip_data {
* We assume the max_frame_retries (7) value of 802.15.4 here.
*/
#define AT86RF2XX_MAX_TX_RETRIES 7
+/* We use the recommended 5 minutes timeout to recalibrate */
+#define AT86RF2XX_CAL_LOOP_TIMEOUT (5 * 60 * HZ)
struct at86rf230_state_change {
struct at86rf230_local *lp;
@@ -90,6 +93,7 @@ struct at86rf230_local {
struct at86rf230_state_change irq;
bool tx_aret;
+ unsigned long cal_timeout;
s8 max_frame_retries;
bool is_tx;
/* spinlock for is_tx protection */
@@ -491,6 +495,14 @@ at86rf230_async_read_reg(struct at86rf230_local *lp, const u8 reg,
}
}
+static inline u8 at86rf230_state_to_force(u8 state)
+{
+ if (state == STATE_TX_ON)
+ return STATE_FORCE_TX_ON;
+ else
+ return STATE_FORCE_TRX_OFF;
+}
+
static void
at86rf230_async_state_assert(void *context)
{
@@ -527,11 +539,12 @@ at86rf230_async_state_assert(void *context)
* higher or equal than AT86RF2XX_MAX_TX_RETRIES we
* will do a force change.
*/
- if (ctx->to_state == STATE_TX_ON) {
- u8 state = STATE_TX_ON;
+ if (ctx->to_state == STATE_TX_ON ||
+ ctx->to_state == STATE_TRX_OFF) {
+ u8 state = ctx->to_state;
if (lp->tx_retry >= AT86RF2XX_MAX_TX_RETRIES)
- state = STATE_FORCE_TX_ON;
+ state = at86rf230_state_to_force(state);
lp->tx_retry++;
at86rf230_async_state_change(lp, ctx, state,
@@ -599,6 +612,11 @@ at86rf230_async_state_delay(void *context)
goto change;
case STATE_TX_ON:
tim = ktime_set(0, c->t_off_to_tx_on * NSEC_PER_USEC);
+ /* state change from TRX_OFF to TX_ON to do a
+ * calibration, we need to reset the timeout for the
+ * next one.
+ */
+ lp->cal_timeout = jiffies + AT86RF2XX_CAL_LOOP_TIMEOUT;
goto change;
default:
break;
@@ -606,10 +624,11 @@ at86rf230_async_state_delay(void *context)
break;
case STATE_BUSY_RX_AACK:
switch (ctx->to_state) {
+ case STATE_TRX_OFF:
case STATE_TX_ON:
/* Wait for worst case receiving time if we
* didn't make a force change from BUSY_RX_AACK
- * to TX_ON.
+ * to TX_ON or TRX_OFF.
*/
if (!force) {
tim = ktime_set(0, (c->t_frame + c->t_p_ack) *
@@ -969,25 +988,45 @@ at86rf230_xmit_tx_on(void *context)
at86rf230_write_frame, false);
}
-static int
-at86rf230_xmit(struct ieee802154_hw *hw, struct sk_buff *skb)
+static void
+at86rf230_xmit_start(void *context)
{
- struct at86rf230_local *lp = hw->priv;
- struct at86rf230_state_change *ctx = &lp->tx;
-
- void (*tx_complete)(void *context) = at86rf230_write_frame;
-
- lp->tx_skb = skb;
+ struct at86rf230_state_change *ctx = context;
+ struct at86rf230_local *lp = ctx->lp;
/* In ARET mode we need to go into STATE_TX_ARET_ON after we
* are in STATE_TX_ON. The pfad differs here, so we change
* the complete handler.
*/
if (lp->tx_aret)
- tx_complete = at86rf230_xmit_tx_on;
+ at86rf230_async_state_change(lp, ctx, STATE_TX_ON,
+ at86rf230_xmit_tx_on, false);
+ else
+ at86rf230_async_state_change(lp, ctx, STATE_TX_ON,
+ at86rf230_write_frame, false);
+}
+
+static int
+at86rf230_xmit(struct ieee802154_hw *hw, struct sk_buff *skb)
+{
+ struct at86rf230_local *lp = hw->priv;
+ struct at86rf230_state_change *ctx = &lp->tx;
+ lp->tx_skb = skb;
lp->tx_retry = 0;
- at86rf230_async_state_change(lp, ctx, STATE_TX_ON, tx_complete, false);
+
+ /* After 5 minutes in PLL and the same frequency we run again the
+ * calibration loops which is recommended by at86rf2xx datasheets.
+ *
+ * The calibration is initiate by a state change from TRX_OFF
+ * to TX_ON, the lp->cal_timeout should be reinit by state_delay
+ * function then to start in the next 5 minutes.
+ */
+ if (time_is_before_jiffies(lp->cal_timeout))
+ at86rf230_async_state_change(lp, ctx, STATE_TRX_OFF,
+ at86rf230_xmit_start, false);
+ else
+ at86rf230_xmit_start(ctx);
return 0;
}
@@ -1003,6 +1042,9 @@ at86rf230_ed(struct ieee802154_hw *hw, u8 *level)
static int
at86rf230_start(struct ieee802154_hw *hw)
{
+ struct at86rf230_local *lp = hw->priv;
+
+ lp->cal_timeout = jiffies + AT86RF2XX_CAL_LOOP_TIMEOUT;
return at86rf230_sync_state_change(hw->priv, STATE_RX_AACK_ON);
}
@@ -1083,6 +1125,8 @@ at86rf230_channel(struct ieee802154_hw *hw, u8 page, u8 channel)
/* Wait for PLL */
usleep_range(lp->data->t_channel_switch,
lp->data->t_channel_switch + 10);
+
+ lp->cal_timeout = jiffies + AT86RF2XX_CAL_LOOP_TIMEOUT;
return rc;
}
--
2.3.0
--
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