linux-kernel - [PATCH 3/3] nvmem: imx-ocotp: add support for post processing

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Date:   Wed, 13 Oct 2021 14:19:57 +0100
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     gregkh@...uxfoundation.org
Cc:     linux-kernel@...r.kernel.org,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Joakim Zhang <qiangqing.zhang@....com>
Subject: [PATCH 3/3] nvmem: imx-ocotp: add support for post processing

Add .cell_post_process callback for imx-ocotp to deal with MAC address,
since MAC address need to be reversed byte for some i.MX SoCs.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Tested-by: Joakim Zhang <qiangqing.zhang@....com>
---
 drivers/nvmem/imx-ocotp.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/nvmem/imx-ocotp.c b/drivers/nvmem/imx-ocotp.c
index 08f41328cc71..14284e866f26 100644
--- a/drivers/nvmem/imx-ocotp.c
+++ b/drivers/nvmem/imx-ocotp.c
@@ -97,6 +97,7 @@ struct ocotp_params {
 	unsigned int bank_address_words;
 	void (*set_timing)(struct ocotp_priv *priv);
 	struct ocotp_ctrl_reg ctrl;
+	bool reverse_mac_address;
 };
 
 static int imx_ocotp_wait_for_busy(struct ocotp_priv *priv, u32 flags)
@@ -221,6 +222,25 @@ static int imx_ocotp_read(void *context, unsigned int offset,
 	return ret;
 }
 
+static int imx_ocotp_cell_pp(void *context, const char *id, unsigned int offset,
+			     void *data, size_t bytes)
+{
+	struct ocotp_priv *priv = context;
+
+	/* Deal with some post processing of nvmem cell data */
+	if (id && !strcmp(id, "mac-address")) {
+		if (priv->params->reverse_mac_address) {
+			u8 *buf = data;
+			int i;
+
+			for (i = 0; i < bytes/2; i++)
+				swap(buf[i], buf[bytes - i - 1]);
+		}
+	}
+
+	return 0;
+}
+
 static void imx_ocotp_set_imx6_timing(struct ocotp_priv *priv)
 {
 	unsigned long clk_rate;
@@ -468,6 +488,7 @@ static struct nvmem_config imx_ocotp_nvmem_config = {
 	.stride = 1,
 	.reg_read = imx_ocotp_read,
 	.reg_write = imx_ocotp_write,
+	.cell_post_process = imx_ocotp_cell_pp,
 };
 
 static const struct ocotp_params imx6q_params = {
@@ -530,6 +551,7 @@ static const struct ocotp_params imx8mq_params = {
 	.bank_address_words = 0,
 	.set_timing = imx_ocotp_set_imx6_timing,
 	.ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
+	.reverse_mac_address = true,
 };
 
 static const struct ocotp_params imx8mm_params = {
@@ -537,6 +559,7 @@ static const struct ocotp_params imx8mm_params = {
 	.bank_address_words = 0,
 	.set_timing = imx_ocotp_set_imx6_timing,
 	.ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
+	.reverse_mac_address = true,
 };
 
 static const struct ocotp_params imx8mn_params = {
@@ -544,6 +567,7 @@ static const struct ocotp_params imx8mn_params = {
 	.bank_address_words = 0,
 	.set_timing = imx_ocotp_set_imx6_timing,
 	.ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
+	.reverse_mac_address = true,
 };
 
 static const struct ocotp_params imx8mp_params = {
@@ -551,6 +575,7 @@ static const struct ocotp_params imx8mp_params = {
 	.bank_address_words = 0,
 	.set_timing = imx_ocotp_set_imx6_timing,
 	.ctrl = IMX_OCOTP_BM_CTRL_8MP,
+	.reverse_mac_address = true,
 };
 
 static const struct of_device_id imx_ocotp_dt_ids[] = {
-- 
2.21.0