diff options
Diffstat (limited to 'drivers/i3c/master/svc-i3c-master.c')
| -rw-r--r-- | drivers/i3c/master/svc-i3c-master.c | 58 |
1 files changed, 44 insertions, 14 deletions
diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c index ccd0c4680be2..acc937275c18 100644 --- a/drivers/i3c/master/svc-i3c-master.c +++ b/drivers/i3c/master/svc-i3c-master.c @@ -1037,29 +1037,59 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master, u8 *in, const u8 *out, unsigned int xfer_len, unsigned int *actual_len, bool continued) { + int retry = 2; u32 reg; int ret; /* clean SVC_I3C_MINT_IBIWON w1c bits */ writel(SVC_I3C_MINT_IBIWON, master->regs + SVC_I3C_MSTATUS); - writel(SVC_I3C_MCTRL_REQUEST_START_ADDR | - xfer_type | - SVC_I3C_MCTRL_IBIRESP_NACK | - SVC_I3C_MCTRL_DIR(rnw) | - SVC_I3C_MCTRL_ADDR(addr) | - SVC_I3C_MCTRL_RDTERM(*actual_len), - master->regs + SVC_I3C_MCTRL); - ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg, + while (retry--) { + writel(SVC_I3C_MCTRL_REQUEST_START_ADDR | + xfer_type | + SVC_I3C_MCTRL_IBIRESP_NACK | + SVC_I3C_MCTRL_DIR(rnw) | + SVC_I3C_MCTRL_ADDR(addr) | + SVC_I3C_MCTRL_RDTERM(*actual_len), + master->regs + SVC_I3C_MCTRL); + + ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg, SVC_I3C_MSTATUS_MCTRLDONE(reg), 0, 1000); - if (ret) - goto emit_stop; + if (ret) + goto emit_stop; - if (readl(master->regs + SVC_I3C_MERRWARN) & SVC_I3C_MERRWARN_NACK) { - ret = -ENXIO; - *actual_len = 0; - goto emit_stop; + if (readl(master->regs + SVC_I3C_MERRWARN) & SVC_I3C_MERRWARN_NACK) { + /* + * According to I3C Spec 1.1.1, 11-Jun-2021, section: 5.1.2.2.3. + * If the Controller chooses to start an I3C Message with an I3C Dynamic + * Address, then special provisions shall be made because that same I3C + * Target may be initiating an IBI or a Controller Role Request. So, one of + * three things may happen: (skip 1, 2) + * + * 3. The Addresses match and the RnW bits also match, and so neither + * Controller nor Target will ACK since both are expecting the other side to + * provide ACK. As a result, each side might think it had "won" arbitration, + * but neither side would continue, as each would subsequently see that the + * other did not provide ACK. + * ... + * For either value of RnW: Due to the NACK, the Controller shall defer the + * Private Write or Private Read, and should typically transmit the Target + * Address again after a Repeated START (i.e., the next one or any one prior + * to a STOP in the Frame). Since the Address Header following a Repeated + * START is not arbitrated, the Controller will always win (see Section + * 5.1.2.2.4). + */ + if (retry && addr != 0x7e) { + writel(SVC_I3C_MERRWARN_NACK, master->regs + SVC_I3C_MERRWARN); + } else { + ret = -ENXIO; + *actual_len = 0; + goto emit_stop; + } + } else { + break; + } } /* |