[PATCH v2 2/9] nvmem: ocotp: add support to get/set srk_revoke sticky bit

[Marco Felsch]

The i.MX8M* devices do have an sticky bit which indicates if the
srk_revoke fuse can be written. Add support to query and to set the lock
bit.

Signed-off-by: Marco Felsch <m.felsch at pengutronix.de>
---
 drivers/nvmem/ocotp.c    | 55 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/mach/imx/ocotp.h |  2 ++
 2 files changed, 57 insertions(+)

diff --git a/drivers/nvmem/ocotp.c b/drivers/nvmem/ocotp.c
index c282efefa824..c0517980fb18 100644
--- a/drivers/nvmem/ocotp.c
+++ b/drivers/nvmem/ocotp.c
@@ -52,6 +52,7 @@
 #define OCOTP_DATA			0x20
 #define OCOTP_READ_CTRL			0x30
 #define OCOTP_READ_FUSE_DATA		0x40
+#define OCOTP_SW_STICKY			0x50
 
 #define MX7_OCOTP_DATA0			0x20
 #define MX7_OCOTP_DATA1			0x30
@@ -89,6 +90,8 @@
 #define OCOTP_TIMING_STROBE_PROG	GENMASK(11, 0)
 #define OCOTP_TIMING_WAIT		GENMASK(27, 22)
 
+#define OCOTP_SW_STICKY_SRK_REVOKE_LOCK		BIT(1)
+
 #define OCOTP_READ_CTRL_READ_FUSE	BIT(1)
 
 #define OCOTP_OFFSET_TO_ADDR(o) (OCOTP_OFFSET_TO_INDEX(o) * 4)
@@ -147,6 +150,8 @@ struct imx_ocotp_data {
 	int (*set_timing)(struct ocotp_priv *priv);
 	int (*fuse_read)(struct ocotp_priv *priv, u32 addr, u32 *pdata);
 	int (*fuse_blow)(struct ocotp_priv *priv, u32 addr, u32 value);
+	bool (*srk_revoke_locked)(struct ocotp_priv *priv);
+	void (*lock_srk_revoke)(struct ocotp_priv *priv);
 	u8  mac_offsets[MAX_MAC_OFFSETS];
 	u8  mac_offsets_num;
 	struct imx8m_featctrl_data *feat;
@@ -273,6 +278,20 @@ static int imx6_ocotp_prepare(struct ocotp_priv *priv)
 	return 0;
 }
 
+static bool imx8m_srk_revoke_locked(struct ocotp_priv *priv)
+{
+	return readl(priv->base + OCOTP_SW_STICKY) & OCOTP_SW_STICKY_SRK_REVOKE_LOCK;
+}
+
+static void imx8m_lock_srk_revoke(struct ocotp_priv *priv)
+{
+	u32 val;
+
+	val = readl(priv->base + OCOTP_SW_STICKY);
+	val |= OCOTP_SW_STICKY_SRK_REVOKE_LOCK;
+	writel(val, priv->base + OCOTP_SW_STICKY);
+}
+
 static int imx6_fuse_read_addr(struct ocotp_priv *priv, u32 addr, u32 *pdata)
 {
 	const u32 bm_ctrl_error = priv->data->ctrl->bm_error;
@@ -625,6 +644,36 @@ int imx_ocotp_sense_enable(bool enable)
 	return old_value;
 }
 
+int imx_ocotp_srk_revoke_locked(void)
+{
+	int ret;
+
+	ret = imx_ocotp_ensure_probed();
+	if (ret)
+		return ret;
+
+	if (imx_ocotp->data->srk_revoke_locked)
+		return imx_ocotp->data->srk_revoke_locked(imx_ocotp);
+
+	return -ENOSYS;
+}
+
+int imx_ocotp_lock_srk_revoke(void)
+{
+	int ret;
+
+	ret = imx_ocotp_ensure_probed();
+	if (ret)
+		return ret;
+
+	if (imx_ocotp->data->lock_srk_revoke) {
+		imx_ocotp->data->lock_srk_revoke(imx_ocotp);
+		return 0;
+	}
+
+	return -ENOSYS;
+}
+
 static void imx_ocotp_format_mac(u8 *dst, const u8 *src,
 				 enum imx_ocotp_format_mac_direction dir)
 {
@@ -985,6 +1034,8 @@ static struct imx_ocotp_data imx8mp_ocotp_data = {
 	.set_timing = imx6_ocotp_set_timing,
 	.fuse_blow = imx6_fuse_blow_addr,
 	.fuse_read = imx6_fuse_read_addr,
+	.srk_revoke_locked = imx8m_srk_revoke_locked,
+	.lock_srk_revoke = imx8m_lock_srk_revoke,
 	.ctrl = &ocotp_ctrl_reg_8mp,
 };
 
@@ -1014,6 +1065,8 @@ static struct imx_ocotp_data imx8mm_ocotp_data = {
 	.set_timing = imx6_ocotp_set_timing,
 	.fuse_blow = imx6_fuse_blow_addr,
 	.fuse_read = imx6_fuse_read_addr,
+	.srk_revoke_locked = imx8m_srk_revoke_locked,
+	.lock_srk_revoke = imx8m_lock_srk_revoke,
 	.feat = &imx8mm_featctrl_data,
 	.ctrl = &ocotp_ctrl_reg_default,
 };
@@ -1032,6 +1085,8 @@ static struct imx_ocotp_data imx8mn_ocotp_data = {
 	.set_timing = imx6_ocotp_set_timing,
 	.fuse_blow = imx6_fuse_blow_addr,
 	.fuse_read = imx6_fuse_read_addr,
+	.srk_revoke_locked = imx8m_srk_revoke_locked,
+	.lock_srk_revoke = imx8m_lock_srk_revoke,
 	.feat = &imx8mn_featctrl_data,
 	.ctrl = &ocotp_ctrl_reg_default,
 };
diff --git a/include/mach/imx/ocotp.h b/include/mach/imx/ocotp.h
index 5f7b88f716a7..7a516ff789b9 100644
--- a/include/mach/imx/ocotp.h
+++ b/include/mach/imx/ocotp.h
@@ -36,6 +36,8 @@ int imx_ocotp_read_field(uint32_t field, unsigned *value);
 int imx_ocotp_write_field(uint32_t field, unsigned value);
 int imx_ocotp_permanent_write(int enable);
 int imx_ocotp_sense_enable(bool enable);
+int imx_ocotp_srk_revoke_locked(void);
+int imx_ocotp_lock_srk_revoke(void);
 
 static inline u64 imx_ocotp_read_uid(void __iomem *ocotp)
 {

-- 
2.39.2