[PATCH v4 02/14] riscv: sifive: fu540: Use OTP DM driver for serial environment variable

[Pragnesh Patel]

Use the OTP DM driver to set the serial environment variable.

Signed-off-by: Pragnesh Patel <pragnesh.patel at sifive.com>
---
 arch/riscv/dts/fu540-c000-u-boot.dtsi         |  14 +++
 .../dts/hifive-unleashed-a00-u-boot.dtsi      |   6 +
 board/sifive/fu540/Kconfig                    |   2 +
 board/sifive/fu540/fu540.c                    | 113 +++++++-----------
 4 files changed, 62 insertions(+), 73 deletions(-)
 create mode 100644 arch/riscv/dts/fu540-c000-u-boot.dtsi
 create mode 100644 arch/riscv/dts/hifive-unleashed-a00-u-boot.dtsi

diff --git a/arch/riscv/dts/fu540-c000-u-boot.dtsi b/arch/riscv/dts/fu540-c000-u-boot.dtsi
new file mode 100644
index 0000000000..31fd113c7d
--- /dev/null
+++ b/arch/riscv/dts/fu540-c000-u-boot.dtsi
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2019 SiFive, Inc
+ */
+
+/ {
+	soc {
+		otp: otp at 10070000 {
+			compatible = "sifive,fu540-otp";
+			reg = <0x0 0x10070000 0x0 0x0FFF>;
+			fuse-count = <0x1000>;
+		};
+	};
+};
diff --git a/arch/riscv/dts/hifive-unleashed-a00-u-boot.dtsi b/arch/riscv/dts/hifive-unleashed-a00-u-boot.dtsi
new file mode 100644
index 0000000000..bec0d19134
--- /dev/null
+++ b/arch/riscv/dts/hifive-unleashed-a00-u-boot.dtsi
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 SiFive, Inc
+ */
+
+#include "fu540-c000-u-boot.dtsi"
diff --git a/board/sifive/fu540/Kconfig b/board/sifive/fu540/Kconfig
index 5ca21474de..900197bbb2 100644
--- a/board/sifive/fu540/Kconfig
+++ b/board/sifive/fu540/Kconfig
@@ -48,5 +48,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	imply SIFIVE_GPIO
 	imply CMD_GPIO
 	imply SMP
+	imply MISC
+	imply SIFIVE_OTP
 
 endif
diff --git a/board/sifive/fu540/fu540.c b/board/sifive/fu540/fu540.c
index 47a2090251..409471effc 100644
--- a/board/sifive/fu540/fu540.c
+++ b/board/sifive/fu540/fu540.c
@@ -10,94 +10,61 @@
 #include <dm.h>
 #include <linux/delay.h>
 #include <linux/io.h>
+#include <misc.h>
 
-#ifdef CONFIG_MISC_INIT_R
-
-#define FU540_OTP_BASE_ADDR			0x10070000
-
-struct fu540_otp_regs {
-	u32 pa;     /* Address input */
-	u32 paio;   /* Program address input */
-	u32 pas;    /* Program redundancy cell selection input */
-	u32 pce;    /* OTP Macro enable input */
-	u32 pclk;   /* Clock input */
-	u32 pdin;   /* Write data input */
-	u32 pdout;  /* Read data output */
-	u32 pdstb;  /* Deep standby mode enable input (active low) */
-	u32 pprog;  /* Program mode enable input */
-	u32 ptc;    /* Test column enable input */
-	u32 ptm;    /* Test mode enable input */
-	u32 ptm_rep;/* Repair function test mode enable input */
-	u32 ptr;    /* Test row enable input */
-	u32 ptrim;  /* Repair function enable input */
-	u32 pwe;    /* Write enable input (defines program cycle) */
-} __packed;
-
-#define BYTES_PER_FUSE				4
-#define NUM_FUSES				0x1000
-
-static int fu540_otp_read(int offset, void *buf, int size)
-{
-	struct fu540_otp_regs *regs = (void __iomem *)FU540_OTP_BASE_ADDR;
-	unsigned int i;
-	int fuseidx = offset / BYTES_PER_FUSE;
-	int fusecount = size / BYTES_PER_FUSE;
-	u32 fusebuf[fusecount];
-
-	/* check bounds */
-	if (offset < 0 || size < 0)
-		return -EINVAL;
-	if (fuseidx >= NUM_FUSES)
-		return -EINVAL;
-	if ((fuseidx + fusecount) > NUM_FUSES)
-		return -EINVAL;
-
-	/* init OTP */
-	writel(0x01, &regs->pdstb); /* wake up from stand-by */
-	writel(0x01, &regs->ptrim); /* enable repair function */
-	writel(0x01, &regs->pce);   /* enable input */
-
-	/* read all requested fuses */
-	for (i = 0; i < fusecount; i++, fuseidx++) {
-		writel(fuseidx, &regs->pa);
-
-		/* cycle clock to read */
-		writel(0x01, &regs->pclk);
-		mdelay(1);
-		writel(0x00, &regs->pclk);
-		mdelay(1);
-
-		/* read the value */
-		fusebuf[i] = readl(&regs->pdout);
-	}
-
-	/* shut down */
-	writel(0, &regs->pce);
-	writel(0, &regs->ptrim);
-	writel(0, &regs->pdstb);
-
-	/* copy out */
-	memcpy(buf, fusebuf, size);
+/*
+ * This define is a value used for error/unknown serial.
+ * If we really care about distinguishing errors and 0 is
+ * valid, we'll need a different one.
+ */
+#define ERROR_READING_SERIAL_NUMBER       0
 
-	return 0;
-}
+#ifdef CONFIG_MISC_INIT_R
 
-static u32 fu540_read_serialnum(void)
+#if CONFIG_IS_ENABLED(SIFIVE_OTP)
+static u32 otp_read_serialnum(struct udevice *dev)
 {
 	int ret;
 	u32 serial[2] = {0};
 
 	for (int i = 0xfe * 4; i > 0; i -= 8) {
-		ret = fu540_otp_read(i, serial, sizeof(serial));
+		ret = misc_read(dev, i, serial, sizeof(serial));
+
 		if (ret) {
-			printf("%s: error reading from OTP\n", __func__);
+			printf("%s: error reading serial from OTP\n", __func__);
 			break;
 		}
+
 		if (serial[0] == ~serial[1])
 			return serial[0];
 	}
 
-	return 0;
+	return ERROR_READING_SERIAL_NUMBER;
+}
+#endif
+
+static u32 fu540_read_serialnum(void)
+{
+	u32 serial = ERROR_READING_SERIAL_NUMBER;
+
+#if CONFIG_IS_ENABLED(SIFIVE_OTP)
+	struct udevice *dev;
+	int ret;
+
+	// init OTP
+	ret = uclass_get_device_by_driver(UCLASS_MISC,
+					  DM_GET_DRIVER(sifive_otp), &dev);
+
+	if (ret) {
+		debug("%s: could not find otp device\n", __func__);
+		return serial;
+	}
+
+	// read serial from OTP and set env var
+	serial = otp_read_serialnum(dev);
+#endif
+
+	return serial;
 }
 
 static void fu540_setup_macaddr(u32 serialnum)
-- 
2.17.1