static int rockchip_rk3399_efuse_read()

in rockchip-efuse.c [150:204]

• 44 lines of code
• 4 McCabe index (conditional complexity)

static int rockchip_rk3399_efuse_read(void *context, unsigned int offset,
				      void *val, size_t bytes)
{
	struct rockchip_efuse_chip *efuse = context;
	unsigned int addr_start, addr_end, addr_offset, addr_len;
	u32 out_value;
	u8 *buf;
	int ret, i = 0;

	ret = clk_prepare_enable(efuse->clk);
	if (ret < 0) {
		dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
		return ret;
	}

	addr_start = rounddown(offset, RK3399_NBYTES) / RK3399_NBYTES;
	addr_end = roundup(offset + bytes, RK3399_NBYTES) / RK3399_NBYTES;
	addr_offset = offset % RK3399_NBYTES;
	addr_len = addr_end - addr_start;

	buf = kzalloc(array3_size(addr_len, RK3399_NBYTES, sizeof(*buf)),
		      GFP_KERNEL);
	if (!buf) {
		clk_disable_unprepare(efuse->clk);
		return -ENOMEM;
	}

	writel(RK3399_LOAD | RK3399_PGENB | RK3399_STROBSFTSEL | RK3399_RSB,
	       efuse->base + REG_EFUSE_CTRL);
	udelay(1);
	while (addr_len--) {
		writel(readl(efuse->base + REG_EFUSE_CTRL) | RK3399_STROBE |
		       ((addr_start++ & RK3399_A_MASK) << RK3399_A_SHIFT),
		       efuse->base + REG_EFUSE_CTRL);
		udelay(1);
		out_value = readl(efuse->base + REG_EFUSE_DOUT);
		writel(readl(efuse->base + REG_EFUSE_CTRL) & (~RK3399_STROBE),
		       efuse->base + REG_EFUSE_CTRL);
		udelay(1);

		memcpy(&buf[i], &out_value, RK3399_NBYTES);
		i += RK3399_NBYTES;
	}

	/* Switch to standby mode */
	writel(RK3399_PD | RK3399_CSB, efuse->base + REG_EFUSE_CTRL);

	memcpy(val, buf + addr_offset, bytes);

	kfree(buf);

	clk_disable_unprepare(efuse->clk);

	return 0;
}