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nvmem: sunxi-sid: add support for H3's SID controller

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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@aosc.xyz>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Icenowy Zheng 2017-03-31 13:44:48 +01:00 committed by Greg Kroah-Hartman
parent 4a72cda530
commit 1a9636426b
2 changed files with 67 additions and 1 deletions
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6
Documentation/devicetree/bindings/nvmem/allwinner,sunxi-sid.txt
View file

@ -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:
"allwinner,sun4i-a10-sid"
"allwinner,sun7i-a20-sid"
"allwinner,sun8i-h3-sid"
- reg: Should contain registers location and length
= Data cells =

62
drivers/nvmem/sunxi_sid.c
View file

@ -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;
@ -138,9 +193,16 @@ static const struct sunxi_sid_cfg sun7i_a20_cfg = {
.size = 0x200,
};
static const struct sunxi_sid_cfg sun8i_h3_cfg = {
.value_offset = 0x200,
.size = 0x100,
.need_register_readout = true,
};
static const struct of_device_id sunxi_sid_of_match[] = {
{ .compatible = "allwinner,sun4i-a10-sid", .data = &sun4i_a10_cfg },
{ .compatible = "allwinner,sun7i-a20-sid", .data = &sun7i_a20_cfg },
{ .compatible = "allwinner,sun8i-h3-sid", .data = &sun8i_h3_cfg },
{/* sentinel */},
};
MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);