diff options
| -rw-r--r-- | drivers/nvmem/sunxi_sid.c | 71 |
1 files changed, 50 insertions, 21 deletions
diff --git a/drivers/nvmem/sunxi_sid.c b/drivers/nvmem/sunxi_sid.c index 99bd54d85fcb..26bb637afe92 100644 --- a/drivers/nvmem/sunxi_sid.c +++ b/drivers/nvmem/sunxi_sid.c @@ -85,13 +85,14 @@ static int sunxi_sid_read(void *context, unsigned int offset, } static int sun8i_sid_register_readout(const struct sunxi_sid *sid, - const unsigned int word) + const unsigned int offset, + u32 *out) { u32 reg_val; int ret; /* Set word, lock access, and set read command */ - reg_val = (word & SUN8I_SID_OFFSET_MASK) + reg_val = (offset & SUN8I_SID_OFFSET_MASK) << SUN8I_SID_OFFSET_SHIFT; reg_val |= SUN8I_SID_OP_LOCK | SUN8I_SID_READ; writel(reg_val, sid->base + SUN8I_SID_PRCTL); @@ -101,7 +102,49 @@ static int sun8i_sid_register_readout(const struct sunxi_sid *sid, if (ret) return ret; + if (out) + *out = readl(sid->base + SUN8I_SID_RDKEY); + writel(0, sid->base + SUN8I_SID_PRCTL); + + return 0; +} + +/* + * On Allwinner H3, the value on the 0x200 offset of the SID controller seems + * to be not reliable at all. + * Read by the registers instead. + */ +static int sun8i_sid_read_byte_by_reg(const struct sunxi_sid *sid, + const unsigned int offset, + u8 *out) +{ + u32 word; + int ret; + + ret = sun8i_sid_register_readout(sid, offset & ~0x03, &word); + + if (ret) + return ret; + + *out = (word >> ((offset & 0x3) * 8)) & 0xff; + + return 0; +} + +static int sun8i_sid_read_by_reg(void *context, unsigned int offset, + void *val, size_t bytes) +{ + struct sunxi_sid *sid = context; + u8 *buf = val; + int ret; + + while (bytes--) { + ret = sun8i_sid_read_byte_by_reg(sid, offset++, buf++); + if (ret) + return ret; + } + return 0; } @@ -131,26 +174,12 @@ static int sunxi_sid_probe(struct platform_device *pdev) size = cfg->size; - if (cfg->need_register_readout) { - /* - * H3's SID controller have a bug that the value at 0x200 - * offset is not the correct value when the hardware is reseted. - * However, after doing a register-based read operation, the - * value become right. - * Do a full read operation here, but ignore its value - * (as it's more fast to read by direct MMIO value than - * with registers) - */ - for (i = 0; i < (size >> 2); i++) { - ret = sun8i_sid_register_readout(sid, i); - if (ret) - return ret; - } - } - econfig.size = size; econfig.dev = dev; - econfig.reg_read = sunxi_sid_read; + if (cfg->need_register_readout) + econfig.reg_read = sun8i_sid_read_by_reg; + else + econfig.reg_read = sunxi_sid_read; econfig.priv = sid; nvmem = nvmem_register(&econfig); if (IS_ERR(nvmem)) @@ -163,7 +192,7 @@ static int sunxi_sid_probe(struct platform_device *pdev) } for (i = 0; i < size; i++) - randomness[i] = sunxi_sid_read_byte(sid, i); + econfig.reg_read(sid, i, &randomness[i], 1); add_device_randomness(randomness, size); kfree(randomness); |