qinlinbin 发布的最佳帖子

spi我也遇到过卡死的问题，不是这个大佬的代码，是代理给的代码。resetfifo后，没等reset结束，直接读数据，就会卡死。我把它改成resetfifo后，判断一下reset完成再进行下一步就不会卡死了。

@yy_fly 仅供参考！！！spi-sunxi.c文件。

/* reset fifo */
static void spi_reset_fifo(void __iomem *base_addr)
{
	u32 reg_val = readl(base_addr + SPI_FIFO_CTL_REG);
	u32 poll_time = 0x7ffffff;
	reg_val |= (SPI_FIFO_CTL_RX_RST|SPI_FIFO_CTL_TX_RST);
	/* Set the trigger level of RxFIFO/TxFIFO. */
	reg_val &= ~(SPI_FIFO_CTL_RX_LEVEL|SPI_FIFO_CTL_TX_LEVEL);
	reg_val |= (0x20<<16) | 0x20;
	writel(reg_val, base_addr + SPI_FIFO_CTL_REG);

        /*添加的内容*/
	reg_val = 0;
	reg_val = readl(base_addr + SPI_FIFO_CTL_REG);
	while((reg_val & SPI_FIFO_CTL_RX_RST || reg_val & SPI_FIFO_CTL_TX_RST) &&
			--poll_time)
		reg_val = readl(base_addr + SPI_FIFO_CTL_REG);
}

static int sunxi_spi_cpu_readl(struct spi_device *spi, struct spi_transfer *t)
{
	struct sunxi_spi *sspi = spi_master_get_devdata(spi->master);
	void __iomem *base_addr = sspi->base_addr;
	unsigned rx_len = t->len;	/* number of bytes sent */
	unsigned char *rx_buf = (unsigned char *)t->rx_buf;
	unsigned int poll_time = 0x7ffffff;
	unsigned int i, j;
	u8 buf[64], cnt = 0;

	while (rx_len && (--poll_time > 0)) {
	/* rxFIFO counter */
		if (spi_query_rxfifo(base_addr)) {
			*rx_buf++ =  readb(base_addr + SPI_RXDATA_REG);
			--rx_len;
		}
	}
        /*余下的没改*/
}

@jr_online 安装bison