[PATCH v3 2/3] nvmem: sunxi-sid: add support for H3's SID controller
Icenowy Zheng
icenowy at aosc.xyz
Mon Feb 6 00:56:55 PST 2017
06.02.2017, 16:54, "Maxime Ripard" <maxime.ripard at free-electrons.com>:
> On Thu, Feb 02, 2017 at 09:13:37PM +0800, Icenowy Zheng wrote:
>> The H3 SoC have a bigger SID controller, which has its direct read
>> address at 0x200 position in the SID block, not 0x0.
>>
>> Also, H3 SID controller has some silicon bug that makes the direct read
>> value wrong at cold boot, add code to workaround the bug. (This bug has
>> already been fixed on A64 and later SoCs)
>>
>> Signed-off-by: Icenowy Zheng <icenowy at aosc.xyz>
>> ---
>> This patch is the part of [PATCH v2 1/1] that adds support for H3 SID
>> controller.
>>
>> .../bindings/nvmem/allwinner,sunxi-sid.txt | 12 +++-
>> drivers/nvmem/sunxi_sid.c | 72 +++++++++++++++++++++-
>> 2 files changed, 82 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/nvmem/allwinner,sunxi-sid.txt b/Documentation/devicetree/bindings/nvmem/allwinner,sunxi-sid.txt
>> index d543ed3f5363..9ab9e75a6351 100644
>> --- a/Documentation/devicetree/bindings/nvmem/allwinner,sunxi-sid.txt
>> +++ b/Documentation/devicetree/bindings/nvmem/allwinner,sunxi-sid.txt
>> @@ -1,7 +1,11 @@
>> Allwinner sunxi-sid
>>
>> Required properties:
>> -- compatible: "allwinner,sun4i-a10-sid" or "allwinner,sun7i-a20-sid"
>> +- compatible: Should be one of the following (depending on your SoC):
>> + "allwinner,sun4i-a10-sid"
>> + "allwinner,sun7i-a20-sid"
>> + "allwinner,sun8i-h3-sid"
>> +
>> - reg: Should contain registers location and length
>>
>> = Data cells =
>> @@ -19,3 +23,9 @@ Example for sun7i:
>> compatible = "allwinner,sun7i-a20-sid";
>> reg = <0x01c23800 0x200>
>> };
>> +
>> +Example for sun8i-h3:
>> + sid at 01c14000 {
>> + compatible = "allwinner,sun8i-h3-sid";
>> + reg = <0x01c14000 0x400>;
>> + };
>> diff --git a/drivers/nvmem/sunxi_sid.c b/drivers/nvmem/sunxi_sid.c
>> index 69524b67007f..476a161ff23a 100644
>> --- a/drivers/nvmem/sunxi_sid.c
>> +++ b/drivers/nvmem/sunxi_sid.c
>> @@ -25,6 +25,16 @@
>> #include <linux/slab.h>
>> #include <linux/random.h>
>>
>> +/* Registers and special values for doing register-based SID readout on H3 */
>> +#define SUN8I_SID_PRCTL 0x40
>> +#define SUN8I_SID_RDKEY 0x60
>> +
>> +#define SUN8I_SID_OP_LOCK 0xAC
>> +#define SUN8I_SID_OFFSET_MASK 0x1FF
>> +#define SUN8I_SID_OFFSET_SHIFT 16
>> +#define SUN8I_SID_LOCK_SHIFT 8
>> +#define SUN8I_SID_READ BIT(1)
>> +
>> static struct nvmem_config econfig = {
>> .name = "sunxi-sid",
>> .read_only = true,
>> @@ -34,11 +44,14 @@ static struct nvmem_config econfig = {
>> };
>>
>> struct sunxi_sid_cfg {
>> + u32 value_offset;
>> u32 size;
>> + bool need_register_readout;
>> };
>>
>> struct sunxi_sid {
>> void __iomem *base;
>> + u32 value_offset;
>> };
>>
>> /* We read the entire key, due to a 32 bit read alignment requirement. Since we
>> @@ -51,7 +64,8 @@ static u8 sunxi_sid_read_byte(const struct sunxi_sid *sid,
>> {
>> u32 sid_key;
>>
>> - sid_key = ioread32be(sid->base + round_down(offset, 4));
>> + sid_key = ioread32be(sid->base + sid->value_offset +
>> + round_down(offset, 4));
>
> This would probably be more logical to have this in sunxi_sid_read.
But it's here which really access the memory...
>
>> sid_key >>= (offset % 4) * 8;
>>
>> return sid_key; /* Only return the last byte */
>> @@ -69,6 +83,33 @@ static int sunxi_sid_read(void *context, unsigned int offset,
>> return 0;
>> }
>>
>> +static int sun8i_sid_register_readout(const struct sunxi_sid *sid,
>> + const unsigned int word,
>> + u32 *out)
>> +{
>> + u32 reg_val;
>> + unsigned long expire = jiffies + msecs_to_jiffies(250);
>> +
>> + /* Set word, lock access, and set read command */
>> + reg_val = (word & SUN8I_SID_OFFSET_MASK)
>> + << SUN8I_SID_OFFSET_SHIFT;
>> + reg_val |= SUN8I_SID_OP_LOCK << SUN8I_SID_LOCK_SHIFT;
>
> You're not using those mask and shifts anywhere else, why not just
> define the value / macro you need directly?
>
>> + reg_val |= SUN8I_SID_READ;
>> + writel(reg_val, sid->base + SUN8I_SID_PRCTL);
>> +
>> + do {
>> + reg_val = readl(sid->base + SUN8I_SID_PRCTL);
>> + } while (time_before(jiffies, expire) && (reg_val & SUN8I_SID_READ));
>
> readl_poll_timeout?
Thanks. I'll check it.
>
>> + if (reg_val & SUN8I_SID_READ)
>> + return -EIO;
>> +
>> + if (out)
>> + *out = readl(sid->base + SUN8I_SID_RDKEY);
>
> Why do you need that out parameter?
The read operation by registers can really return a value --
in fact, the fix to the pre-read value is a side effect.
>
> Thanks,
> Maxime
>
> --
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com
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