diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c index c0299e3f2cf8..6b0ec74313d3 100644 --- a/drivers/i3c/master/svc-i3c-master.c +++ b/drivers/i3c/master/svc-i3c-master.c @@ -113,6 +113,7 @@ #define SVC_I3C_MWDATAHE 0x0BC #define SVC_I3C_MRDATAB 0x0C0 #define SVC_I3C_MRDATAH 0x0C8 +#define SVC_I3C_MWDATAB1 0x0CC #define SVC_I3C_MWMSG_SDR 0x0D0 #define SVC_I3C_MRMSG_SDR 0x0D4 #define SVC_I3C_MWMSG_DDR 0x0D8 @@ -133,6 +134,16 @@ #define SVC_I3C_EVENT_IBI GENMASK(7, 0) #define SVC_I3C_EVENT_HOTJOIN BIT(31) +/* + * SVC_I3C_QUIRK_FIFO_EMPTY: + * I3C HW stalls the write transfer if the transmit FIFO becomes empty, + * when new data is written to FIFO, I3C HW resumes the transfer but + * the first transmitted data bit may have the wrong value. + * Workaround: + * Fill the FIFO in advance to prevent FIFO from becoming empty. + */ +#define SVC_I3C_QUIRK_FIFO_EMPTY BIT(0) + struct svc_i3c_cmd { u8 addr; bool rnw; @@ -236,6 +247,11 @@ struct svc_i3c_i2c_dev_data { struct i3c_generic_ibi_pool *ibi_pool; }; +static inline bool svc_has_quirk(struct svc_i3c_master *master, u32 quirk) +{ + return (master->drvdata->quirks & quirk); +} + static inline bool is_events_enabled(struct svc_i3c_master *master, u32 mask) { return !!(master->enabled_events & mask); @@ -894,7 +910,7 @@ static int svc_i3c_master_do_daa_locked(struct svc_i3c_master *master, u8 *addrs, unsigned int *count) { u64 prov_id[SVC_I3C_MAX_DEVS] = {}, nacking_prov_id = 0; - unsigned int dev_nb = 0, last_addr = 0; + unsigned int dev_nb = 0, last_addr = 0, dyn_addr; u32 reg; int ret, i; @@ -939,6 +955,25 @@ static int svc_i3c_master_do_daa_locked(struct svc_i3c_master *master, if (SVC_I3C_MSTATUS_RXPEND(reg)) { u8 data[6]; + /* + * One slave sends its ID to request for address assignment, + * prefilling the dynamic address can reduce SCL clock stalls + * and also fix the SVC_I3C_QUIRK_FIFO_EMPTY quirk. + * + * Ideally, prefilling before the processDAA command is better. + * However, it requires an additional check to write the dyn_addr + * at the right time because the driver needs to write the processDAA + * command twice for one assignment. + * Prefilling here is safe and efficient because the FIFO starts + * filling within a few hundred nanoseconds, which is significantly + * faster compared to the 64 SCL clock cycles. + */ + dyn_addr = i3c_master_get_free_addr(&master->base, last_addr + 1); + if (dyn_addr < 0) + return -ENOSPC; + + writel(dyn_addr, master->regs + SVC_I3C_MWDATAB); + /* * We only care about the 48-bit provisioned ID yet to * be sure a device does not nack an address twice. @@ -1017,21 +1052,16 @@ static int svc_i3c_master_do_daa_locked(struct svc_i3c_master *master, if (ret) break; - /* Give the slave device a suitable dynamic address */ - ret = i3c_master_get_free_addr(&master->base, last_addr + 1); - if (ret < 0) - break; - - addrs[dev_nb] = ret; + addrs[dev_nb] = dyn_addr; dev_dbg(master->dev, "DAA: device %d assigned to 0x%02x\n", dev_nb, addrs[dev_nb]); - - writel(addrs[dev_nb], master->regs + SVC_I3C_MWDATAB); last_addr = addrs[dev_nb++]; } /* Need manual issue STOP except for Complete condition */ svc_i3c_master_emit_stop(master); + svc_i3c_master_flush_fifo(master); + return ret; } @@ -1228,6 +1258,24 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master, SVC_I3C_MCTRL_RDTERM(*actual_len), master->regs + SVC_I3C_MCTRL); + /* + * The entire transaction can consist of multiple write transfers. + * Prefilling before EmitStartAddr causes the data to be emitted + * immediately, becoming part of the previous transfer. + * The only way to work around this hardware issue is to let the + * FIFO start filling as soon as possible after EmitStartAddr. + */ + if (svc_has_quirk(master, SVC_I3C_QUIRK_FIFO_EMPTY) && !rnw && xfer_len) { + u32 end = xfer_len > SVC_I3C_FIFO_SIZE ? 0 : SVC_I3C_MWDATAB_END; + u32 len = min_t(u32, xfer_len, SVC_I3C_FIFO_SIZE); + + writesb(master->regs + SVC_I3C_MWDATAB1, out, len - 1); + /* Mark END bit if this is the last byte */ + writel(out[len - 1] | end, master->regs + SVC_I3C_MWDATAB); + xfer_len -= len; + out += len; + } + ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg, SVC_I3C_MSTATUS_MCTRLDONE(reg), 0, 1000); if (ret) @@ -1316,6 +1364,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master, emit_stop: svc_i3c_master_emit_stop(master); svc_i3c_master_clear_merrwarn(master); + svc_i3c_master_flush_fifo(master); return ret; } @@ -1970,7 +2019,9 @@ static const struct dev_pm_ops svc_i3c_pm_ops = { svc_i3c_runtime_resume, NULL) }; -static const struct svc_i3c_drvdata npcm845_drvdata = {}; +static const struct svc_i3c_drvdata npcm845_drvdata = { + .quirks = SVC_I3C_QUIRK_FIFO_EMPTY, +}; static const struct svc_i3c_drvdata svc_default_drvdata = {};