前言

在使用ast2400从机驱动中，当从机设备在被读取时丢失数据，仅仅在偶数时丢失。故对官方驱动做出相应的修改。

openbmc开发包的使用、ast2400配置、uboot修改、其他驱动、device-tree等修改见其他文档。

首次写博客，速度和文档质量不做保障，只保障代码质量，请各位看客谅解。

ast2400 内核修改启用i2c从机模拟eeprom

> Device Drivers > I2C support
[*] I2C slave support
[*] I2C eeprom slave driver

测试驱动

在linux-aspeed/Documentation/i2c/slave-eeprom-backend.rst手册中有描述如何使用slave EEPROM驱动
注：设备树或者其他信息都可以在Documentation目录下找到对应的描述

注意时间差，aspeed官方驱动在读取时ack应答间隔不一致，会导致数据丢失
读取处理时，接收ASPEED_I2CD_INTR_TX_ACK中断和ASPEED_I2CD_INTR_RX_DONE中断状态分时处里了，
本人理解为ACK的接收同样也应触发接收中断，故将终端状态合并ASPEED_I2CD_INTR_TX_ACK|ASPEED_I2CD_INTR_RX_DONE
并进行统一处理

ast2400 i2c-aspeed.c 驱动修改

以下为修改的函数

static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
{u32 command, irq_handled = 0;struct i2c_client *slave = bus->slave;u8 value;if (!slave)return 0;command = readl(bus->base + ASPEED_I2C_CMD_REG);/* Slave was requested, restart state machine. */if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {irq_handled |= ASPEED_I2CD_INTR_SLAVE_MATCH;bus->slave_state = ASPEED_I2C_SLAVE_START;}/* Slave is not currently active, irq was for someone else. */if (bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE)return irq_handled;dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n",irq_status, command);/* Slave was sent something. */if (irq_status & ASPEED_I2CD_INTR_RX_DONE) {value = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;/* Handle address frame. */if (bus->slave_state == ASPEED_I2C_SLAVE_START) {if (value & 0x1)bus->slave_state =ASPEED_I2C_SLAVE_READ_REQUESTED;elsebus->slave_state =ASPEED_I2C_SLAVE_WRITE_REQUESTED;}irq_handled |= ASPEED_I2CD_INTR_RX_DONE;}/* Slave was asked to stop. */if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;bus->slave_state = ASPEED_I2C_SLAVE_STOP;}if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {irq_handled |= ASPEED_I2CD_INTR_TX_NAK;bus->slave_state = ASPEED_I2C_SLAVE_STOP;}switch (bus->slave_state) {case ASPEED_I2C_SLAVE_READ_REQUESTED:if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_ACK))dev_err(bus->dev, "Unexpected ACK on read request.\n");bus->slave_state = ASPEED_I2C_SLAVE_READ_PROCESSED;i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value);// printk("slave send value %x\n", value);writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG);writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG);break;case ASPEED_I2C_SLAVE_READ_PROCESSED:#if 0 /*aspeed*/if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {dev_err(bus->dev,"Expected ACK after processed read.\n");break;}irq_handled |= ASPEED_I2CD_INTR_TX_ACK;#else /*wish*/irq_handled |= ASPEED_I2CD_INTR_TX_ACK|ASPEED_I2CD_INTR_RX_DONE;#endif i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value);// printk("slave send value %x\n", value);writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG);writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG);break;case ASPEED_I2C_SLAVE_WRITE_REQUESTED:bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);break;case ASPEED_I2C_SLAVE_WRITE_RECEIVED:i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);break;case ASPEED_I2C_SLAVE_STOP:i2c_slave_event(slave, I2C_SLAVE_STOP, &value);bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;break;case ASPEED_I2C_SLAVE_START:/* Slave was just started. Waiting for the next event. */;break;default:dev_err(bus->dev, "unknown slave_state: %d\n",bus->slave_state);bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;break;}return irq_handled;
}
static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
{struct aspeed_i2c_bus *bus = dev_id;u32 irq_received, irq_remaining, irq_handled;spin_lock(&bus->lock);irq_received = readl(bus->base + ASPEED_I2C_INTR_STS_REG);/* Ack all interrupts except for Rx done */#if 0 /*aspeed*/writel(irq_received & ~ASPEED_I2CD_INTR_RX_DONE,bus->base + ASPEED_I2C_INTR_STS_REG);#else /*wish*/if(bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED){if(irq_received == ASPEED_I2CD_INTR_TX_ACK){// printk("irq_received & ASPEED_I2CD_INTR_TX_ACK");irq_received |= ASPEED_I2CD_INTR_RX_DONE;}// 该分支因为修改后不会在发生，所以注释// if(irq_received == ASPEED_I2CD_INTR_RX_DONE){//   printk("irq_received & ASPEED_I2CD_INTR_RX_DONE");//  irq_received |= ASPEED_I2CD_INTR_TX_ACK;// }writel(irq_received & ~(ASPEED_I2CD_INTR_RX_DONE|ASPEED_I2CD_INTR_TX_ACK),bus->base + ASPEED_I2C_INTR_STS_REG);}else{writel(irq_received & ~ASPEED_I2CD_INTR_RX_DONE,bus->base + ASPEED_I2C_INTR_STS_REG);}#endifreadl(bus->base + ASPEED_I2C_INTR_STS_REG);irq_received &= ASPEED_I2CD_INTR_RECV_MASK;irq_remaining = irq_received;#if IS_ENABLED(CONFIG_I2C_SLAVE)/** In most cases, interrupt bits will be set one by one, although* multiple interrupt bits could be set at the same time. It's also* possible that master interrupt bits could be set along with slave* interrupt bits. Each case needs to be handled using corresponding* handlers depending on the current state.*/if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE &&bus->master_state != ASPEED_I2C_MASTER_PENDING) {irq_handled = aspeed_i2c_master_irq(bus, irq_remaining);irq_remaining &= ~irq_handled;if (irq_remaining)irq_handled |= aspeed_i2c_slave_irq(bus, irq_remaining);} else {// printk("irq_remaining %x\n", irq_remaining);irq_handled = aspeed_i2c_slave_irq(bus, irq_remaining);// printk("irq_handled %x\n", irq_handled);irq_remaining &= ~irq_handled;if (irq_remaining)// printk("master_irq %x\n", irq_remaining);irq_handled |= aspeed_i2c_master_irq(bus,irq_remaining);}/** Start a pending master command at here if a slave operation is* completed.*/if (bus->master_state == ASPEED_I2C_MASTER_PENDING &&bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE)aspeed_i2c_do_start(bus);
#elseirq_handled = aspeed_i2c_master_irq(bus, irq_remaining);
#endif /* CONFIG_I2C_SLAVE */irq_remaining &= ~irq_handled;if (irq_remaining)dev_err(bus->dev,"irq handled != irq. expected 0x%08x, but was 0x%08x\n",irq_received, irq_handled);/* Ack Rx done */#if 0 /*aspeed*/if (irq_received & ASPEED_I2CD_INTR_RX_DONE) {writel(ASPEED_I2CD_INTR_RX_DONE,bus->base + ASPEED_I2C_INTR_STS_REG);readl(bus->base + ASPEED_I2C_INTR_STS_REG); }#else /*wish*/if (irq_received & ASPEED_I2CD_INTR_RX_DONE) {if (irq_received == (ASPEED_I2CD_INTR_RX_DONE|ASPEED_I2CD_INTR_TX_ACK)) {// printk("ack rx down\n");writel(ASPEED_I2CD_INTR_RX_DONE|ASPEED_I2CD_INTR_TX_ACK,bus->base + ASPEED_I2C_INTR_STS_REG);readl(bus->base + ASPEED_I2C_INTR_STS_REG);}else{// printk("other rx down\n");writel(ASPEED_I2CD_INTR_RX_DONE,bus->base + ASPEED_I2C_INTR_STS_REG);readl(bus->base + ASPEED_I2C_INTR_STS_REG);} }// 测试统一都按ASPEED_I2CD_INTR_RX_DONE|ASPEED_I2CD_INTR_TX_ACK处理十分会有其他错误// if (irq_received & ASPEED_I2CD_INTR_RX_DONE){//  writel(ASPEED_I2CD_INTR_RX_DONE|ASPEED_I2CD_INTR_TX_ACK,//          bus->base + ASPEED_I2C_INTR_STS_REG);//     readl(bus->base + ASPEED_I2C_INTR_STS_REG);// }#endif spin_unlock(&bus->lock);return irq_remaining ? IRQ_NONE : IRQ_HANDLED;
}

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openbmc开发--＞aspeed--＞slave-i2c[ast2400]

openbmc开发--＞aspeed--＞slave-i2c[ast2400]

前言

ast2400 内核修改启用i2c从机模拟eeprom

测试驱动

ast2400 i2c-aspeed.c 驱动修改

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