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ig4: Fix FIFO depths detection

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At least on my Tiger Lake-LP queue depth detection failed before the
ig4iic_set_config() call, resulting in no FIFO use.  Moving it after
solves the problem, getting proper 64 bytes size.

On my Dell XPS 13 9310 with iichid(4) touchscreen and touchpad this
by few times reduces context switch rate in the driver, and probably
also improves the I2C bus utilization.

MFC after:	1 month
This commit is contained in:
Alexander Motin 2023-12-23 19:02:49 -05:00
parent a74df3f96e
commit 9c9d7fdd9f
1 changed files with 31 additions and 19 deletions
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50
sys/dev/ichiic/ig4_iic.c
View file

@ -850,23 +850,6 @@ ig4iic_get_config(ig4iic_softc_t *sc)
sc->cfg.txfifo_depth = IG4_PARAM1_TXFIFO_DEPTH(v);
if (IG4_PARAM1_RXFIFO_DEPTH(v) != 0)
sc->cfg.rxfifo_depth = IG4_PARAM1_RXFIFO_DEPTH(v);
} else {
/*
* Hardware does not allow FIFO Threshold Levels value to be
* set larger than the depth of the buffer. If an attempt is
* made to do that, the actual value set will be the maximum
* depth of the buffer.
*/
v = reg_read(sc, IG4_REG_TX_TL);
reg_write(sc, IG4_REG_TX_TL, v | IG4_FIFO_MASK);
sc->cfg.txfifo_depth =
(reg_read(sc, IG4_REG_TX_TL) & IG4_FIFO_MASK) + 1;
reg_write(sc, IG4_REG_TX_TL, v);
v = reg_read(sc, IG4_REG_RX_TL);
reg_write(sc, IG4_REG_RX_TL, v | IG4_FIFO_MASK);
sc->cfg.rxfifo_depth =
(reg_read(sc, IG4_REG_RX_TL) & IG4_FIFO_MASK) + 1;
reg_write(sc, IG4_REG_RX_TL, v);
}
/* Override hardware config with IC_clock-based counter values */
@ -918,8 +901,6 @@ ig4iic_get_config(ig4iic_softc_t *sc)
printf(" Fast: 0x%04hx:0x%04hx:0x%04hx\n",
sc->cfg.fs_scl_hcnt, sc->cfg.fs_scl_lcnt,
sc->cfg.fs_sda_hold);
printf(" FIFO: RX:0x%04x: TX:0x%04x\n",
sc->cfg.rxfifo_depth, sc->cfg.txfifo_depth);
}
}
@ -1015,6 +996,36 @@ ig4iic_set_config(ig4iic_softc_t *sc, bool reset)
return (0);
}
static void
ig4iic_get_fifo(ig4iic_softc_t *sc)
{
uint32_t v;
/*
* Hardware does not allow FIFO Threshold Levels value to be set larger
* than the depth of the buffer. If an attempt is made to do that, the
* actual value set will be the maximum depth of the buffer.
*/
if (sc->cfg.txfifo_depth == 0) {
v = reg_read(sc, IG4_REG_TX_TL);
reg_write(sc, IG4_REG_TX_TL, v | IG4_FIFO_MASK);
sc->cfg.txfifo_depth =
(reg_read(sc, IG4_REG_TX_TL) & IG4_FIFO_MASK) + 1;
reg_write(sc, IG4_REG_TX_TL, v);
}
if (sc->cfg.rxfifo_depth == 0) {
v = reg_read(sc, IG4_REG_RX_TL);
reg_write(sc, IG4_REG_RX_TL, v | IG4_FIFO_MASK);
sc->cfg.rxfifo_depth =
(reg_read(sc, IG4_REG_RX_TL) & IG4_FIFO_MASK) + 1;
reg_write(sc, IG4_REG_RX_TL, v);
}
if (bootverbose) {
printf(" FIFO: RX:0x%04x: TX:0x%04x\n",
sc->cfg.rxfifo_depth, sc->cfg.txfifo_depth);
}
}
/*
* Called from ig4iic_pci_attach/detach()
*/
@ -1031,6 +1042,7 @@ ig4iic_attach(ig4iic_softc_t *sc)
error = ig4iic_set_config(sc, IG4_HAS_ADDREGS(sc->version));
if (error)
goto done;
ig4iic_get_fifo(sc);
sc->iicbus = device_add_child(sc->dev, "iicbus", -1);
if (sc->iicbus == NULL) {