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Date: Mon, 27 Feb 2017 10:58:19 +0100
From: Maxime Ripard <maxime.ripard@...e-electrons.com>
To: Icenowy Zheng <icenowy@...c.xyz>
Cc: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
Rob Herring <robh+dt@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, linux-sunxi@...glegroups.com
Subject: Re: [PATCH v4 2/3] nvmem: sunxi-sid: add support for H3's SID
controller
On Mon, Feb 27, 2017 at 12:10:02AM +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@...c.xyz>
> ---
> Changes in v4:
> - Use readl_poll_timeout.
> - Do register offset in sunxi_sid_read.
> - Merge SUN8I_SID_OP_LOCK and SUN8I_SID_LOCK_SHIFT into one macro.
> - Drop the result of register-based read operation.
>
> .../bindings/nvmem/allwinner,sunxi-sid.txt | 12 +++-
> drivers/nvmem/sunxi_sid.c | 66 ++++++++++++++++++++++
> 2 files changed, 77 insertions(+), 1 deletion(-)
>
> 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):
There's no need to add that it depends on the SoC, it's kind of obvious.
> + "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@...14000 {
> + compatible = "allwinner,sun8i-h3-sid";
> + reg = <0x01c14000 0x400>;
> + };
And there's no need to add an example either, this is just as obvious
if you compare it to the other.
> diff --git a/drivers/nvmem/sunxi_sid.c b/drivers/nvmem/sunxi_sid.c
> index 69524b67007f..5179add54749 100644
> --- a/drivers/nvmem/sunxi_sid.c
> +++ b/drivers/nvmem/sunxi_sid.c
> @@ -17,6 +17,7 @@
>
> #include <linux/device.h>
> #include <linux/io.h>
> +#include <linux/iopoll.h>
> #include <linux/module.h>
> #include <linux/nvmem-provider.h>
> #include <linux/of.h>
> @@ -25,6 +26,15 @@
> #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_OFFSET_MASK 0x1FF
> +#define SUN8I_SID_OFFSET_SHIFT 16
> +#define SUN8I_SID_OP_LOCK (0xAC << 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
> @@ -63,12 +76,36 @@ static int sunxi_sid_read(void *context, unsigned int offset,
> struct sunxi_sid *sid = context;
> u8 *buf = val;
>
> + /* Offset the read operation to the real position of SID */
> + offset += sid->value_offset;
> +
> while (bytes--)
> *buf++ = sunxi_sid_read_byte(sid, offset++);
>
> return 0;
> }
>
> +static int sun8i_sid_register_readout(const struct sunxi_sid *sid,
> + const unsigned int word)
> +{
> + u32 reg_val;
> + int ret;
> +
> + /* 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_READ;
> + writel(reg_val, sid->base + SUN8I_SID_PRCTL);
> +
> + ret = readl_poll_timeout(sid->base + SUN8I_SID_PRCTL, reg_val,
> + !(reg_val & SUN8I_SID_READ), 100, 250000);
> + if (ret)
> + return ret;
> +
> + writel(0, sid->base + SUN8I_SID_PRCTL);
> + return 0;
> +}
> +
> static int sunxi_sid_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> @@ -86,6 +123,7 @@ static int sunxi_sid_probe(struct platform_device *pdev)
> cfg = of_device_get_match_data(dev);
> if (!cfg)
> return -EINVAL;
> + sid->value_offset = cfg->value_offset;
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> sid->base = devm_ioremap_resource(dev, res);
> @@ -94,6 +132,23 @@ 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;
> @@ -131,16 +186,27 @@ static int sunxi_sid_remove(struct platform_device *pdev)
> }
>
> static const struct sunxi_sid_cfg sun4i_a10_cfg = {
> + .value_offset = 0,
This is already the default value
> .size = 0x10,
> + .need_register_readout = false,
And here too
> };
>
> static const struct sunxi_sid_cfg sun7i_a20_cfg = {
> + .value_offset = 0,
> .size = 0x200,
> + .need_register_readout = false,
Ditto.
Thanks!
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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