RE: [PATCH 2/2] nvmem: imx: scu: support write

[Peng Fan]

Hi Srinivas,

> >> Subject: [PATCH 2/2] nvmem: imx: scu: support write
> >
> > Ping..
> >
> Thanks for your patience!
> I normally do not take patches after rc5 for nvmem.
> These will be applied after rc1 is released!

Sorry to ping again. Will you pick up since merge window is open?

Thanks,
Peng.

> 
> Thanks,
> srini
> > Thanks,
> > Peng.
> >
> >>
> >> From: Peng Fan <peng.fan@xxxxxxx>
> >>
> >> The fuse programming from non-secure world is blocked, so we could
> >> only use Arm Trusted Firmware SIP call to let ATF program fuse.
> >>
> >> Because there is ECC region that could only be programmed once, so
> >> add a heler in_ecc to check the ecc region.
> >>
> >> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> >> ---
> >>
> >> The ATF patch will soon be posted to ATF community.
> >>
> >>   drivers/nvmem/imx-ocotp-scu.c | 73
> >> ++++++++++++++++++++++++++++++++++++++++++-
> >>   1 file changed, 72 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/nvmem/imx-ocotp-scu.c
> >> b/drivers/nvmem/imx-ocotp-scu.c index 2f339d7432e6..0f064f2e74a8
> >> 100644
> >> --- a/drivers/nvmem/imx-ocotp-scu.c
> >> +++ b/drivers/nvmem/imx-ocotp-scu.c
> >> @@ -7,6 +7,7 @@
> >>    * Peng Fan <peng.fan@xxxxxxx>
> >>    */
> >>
> >> +#include <linux/arm-smccc.h>
> >>   #include <linux/firmware/imx/sci.h>
> >>   #include <linux/module.h>
> >>   #include <linux/nvmem-provider.h>
> >> @@ -14,6 +15,9 @@
> >>   #include <linux/platform_device.h>
> >>   #include <linux/slab.h>
> >>
> >> +#define IMX_SIP_OTP			0xC200000A
> >> +#define IMX_SIP_OTP_WRITE		0x2
> >> +
> >>   enum ocotp_devtype {
> >>   	IMX8QXP,
> >>   };
> >> @@ -45,6 +49,8 @@ struct imx_sc_msg_misc_fuse_read {
> >>   	u32 word;
> >>   } __packed;
> >>
> >> +static DEFINE_MUTEX(scu_ocotp_mutex);
> >> +
> >>   static struct ocotp_devtype_data imx8qxp_data = {
> >>   	.devtype = IMX8QXP,
> >>   	.nregs = 800,
> >> @@ -73,6 +79,23 @@ static bool in_hole(void *context, u32 index)
> >>   	return false;
> >>   }
> >>
> >> +static bool in_ecc(void *context, u32 index) {
> >> +	struct ocotp_priv *priv = context;
> >> +	const struct ocotp_devtype_data *data = priv->data;
> >> +	int i;
> >> +
> >> +	for (i = 0; i < data->num_region; i++) {
> >> +		if (data->region[i].flag & ECC_REGION) {
> >> +			if ((index >= data->region[i].start) &&
> >> +			    (index <= data->region[i].end))
> >> +				return true;
> >> +		}
> >> +	}
> >> +
> >> +	return false;
> >> +}
> >> +
> >>   static int imx_sc_misc_otp_fuse_read(struct imx_sc_ipc *ipc, u32
> word,
> >>   				     u32 *val)
> >>   {
> >> @@ -116,6 +139,8 @@ static int imx_scu_ocotp_read(void *context,
> >> unsigned int offset,
> >>   	if (!p)
> >>   		return -ENOMEM;
> >>
> >> +	mutex_lock(&scu_ocotp_mutex);
> >> +
> >>   	buf = p;
> >>
> >>   	for (i = index; i < (index + count); i++) { @@ -126,6 +151,7 @@
> >> static int imx_scu_ocotp_read(void *context, unsigned int offset,
> >>
> >>   		ret = imx_sc_misc_otp_fuse_read(priv->nvmem_ipc, i, buf);
> >>   		if (ret) {
> >> +			mutex_unlock(&scu_ocotp_mutex);
> >>   			kfree(p);
> >>   			return ret;
> >>   		}
> >> @@ -134,18 +160,63 @@ static int imx_scu_ocotp_read(void *context,
> >> unsigned int offset,
> >>
> >>   	memcpy(val, (u8 *)p + offset % 4, bytes);
> >>
> >> +	mutex_unlock(&scu_ocotp_mutex);
> >> +
> >>   	kfree(p);
> >>
> >>   	return 0;
> >>   }
> >>
> >> +static int imx_scu_ocotp_write(void *context, unsigned int offset,
> >> +			       void *val, size_t bytes)
> >> +{
> >> +	struct ocotp_priv *priv = context;
> >> +	struct arm_smccc_res res;
> >> +	u32 *buf = val;
> >> +	u32 tmp;
> >> +	u32 index;
> >> +	int ret;
> >> +
> >> +	/* allow only writing one complete OTP word at a time */
> >> +	if ((bytes != 4) || (offset % 4))
> >> +		return -EINVAL;
> >> +
> >> +	index = offset >> 2;
> >> +
> >> +	if (in_hole(context, index))
> >> +		return -EINVAL;
> >> +
> >> +	if (in_ecc(context, index)) {
> >> +		pr_warn("ECC region, only program once\n");
> >> +		mutex_lock(&scu_ocotp_mutex);
> >> +		ret = imx_sc_misc_otp_fuse_read(priv->nvmem_ipc, index, &tmp);
> >> +		mutex_unlock(&scu_ocotp_mutex);
> >> +		if (ret)
> >> +			return ret;
> >> +		if (tmp) {
> >> +			pr_warn("ECC region, already has value: %x\n", tmp);
> >> +			return -EIO;
> >> +		}
> >> +	}
> >> +
> >> +	mutex_lock(&scu_ocotp_mutex);
> >> +
> >> +	arm_smccc_smc(IMX_SIP_OTP, IMX_SIP_OTP_WRITE, index, *buf,
> >> +		      0, 0, 0, 0, &res);
> >> +
> >> +	mutex_unlock(&scu_ocotp_mutex);
> >> +
> >> +	return res.a0;
> >> +}
> >> +
> >>   static struct nvmem_config imx_scu_ocotp_nvmem_config = {
> >>   	.name = "imx-scu-ocotp",
> >> -	.read_only = true,
> >> +	.read_only = false,
> >>   	.word_size = 4,
> >>   	.stride = 1,
> >>   	.owner = THIS_MODULE,
> >>   	.reg_read = imx_scu_ocotp_read,
> >> +	.reg_write = imx_scu_ocotp_write,
> >>   };
> >>
> >>   static const struct of_device_id imx_scu_ocotp_dt_ids[] = {
> >> --
> >> 2.16.4
> >