Messages in this thread | | | Subject | Re: [PATCH 02/10] i2c: xiic: Add standard mode support for > 255 byte read transfers | From | Marek Vasut <> | Date | Wed, 2 Jun 2021 13:17:10 +0200 |
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On 5/31/21 3:19 PM, Raviteja Narayanam wrote:
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> + if (i2c->dynamic) { > + u8 bytes; > + u16 val; > + > + /* Clear and enable Rx full interrupt. */ > + xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | > + XIIC_INTR_TX_ERROR_MASK); > + > + /* > + * We want to get all but last byte, because the TX_ERROR IRQ > + * is used to indicate error ACK on the address, and > + * negative ack on the last received byte, so to not mix > + * them receive all but last. > + * In the case where there is only one byte to receive > + * we can check if ERROR and RX full is set at the same time > + */ > + rx_watermark = msg->len; > + bytes = min_t(u8, rx_watermark, IIC_RX_FIFO_DEPTH); > + bytes--; > + > + xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, bytes); > + > + local_irq_save(flags); > + if (!(msg->flags & I2C_M_NOSTART)) > + /* write the address */ > + xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, > + i2c_8bit_addr_from_msg(msg) | > + XIIC_TX_DYN_START_MASK); > + > + xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK); > + > + /* If last message, include dynamic stop bit with length */ > + val = (i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0; > + val |= msg->len; > + > + xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, val); > + local_irq_restore(flags);
Is local_irq_save()/local_irq_restore() used here to prevent concurrent access to the XIIC ?
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