[PATCH v13 01/19] misc: add driver for the SiFive otp controller

[Pragnesh Patel]

Added a misc driver to handle OTP memory in SiFive SoCs.

Signed-off-by: Pragnesh Patel <pragnesh.patel at sifive.com>
Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
Tested-by: Bin Meng <bmeng.cn at gmail.com>
Reviewed-by: Jagan Teki <jagan at amarulasolutions.com>
Tested-by: Jagan Teki <jagan at amarulasolutions.com>
---
 drivers/misc/Kconfig      |   7 +
 drivers/misc/Makefile     |   1 +
 drivers/misc/sifive-otp.c | 275 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 283 insertions(+)
 create mode 100644 drivers/misc/sifive-otp.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 81ed9eb209..6bb5bc77e9 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -68,6 +68,13 @@ config ROCKCHIP_OTP
 	  addressing and a length or through child-nodes that are generated
 	  based on the e-fuse map retrieved from the DTS.
 
+config SIFIVE_OTP
+	bool "SiFive eMemory OTP driver"
+	depends on MISC
+	help
+	  Enable support for reading and writing the eMemory OTP on the
+	  SiFive SoCs.
+
 config VEXPRESS_CONFIG
 	bool "Enable support for Arm Versatile Express config bus"
 	depends on MISC
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 68e0e7ad17..947bd3a647 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_QFW) += qfw.o
 obj-$(CONFIG_ROCKCHIP_EFUSE) += rockchip-efuse.o
 obj-$(CONFIG_ROCKCHIP_OTP) += rockchip-otp.o
 obj-$(CONFIG_SANDBOX) += syscon_sandbox.o misc_sandbox.o
+obj-$(CONFIG_SIFIVE_OTP) += sifive-otp.o
 obj-$(CONFIG_SMSC_LPC47M) += smsc_lpc47m.o
 obj-$(CONFIG_SMSC_SIO1007) += smsc_sio1007.o
 obj-$(CONFIG_STM32MP_FUSE) += stm32mp_fuse.o
diff --git a/drivers/misc/sifive-otp.c b/drivers/misc/sifive-otp.c
new file mode 100644
index 0000000000..92f08dde01
--- /dev/null
+++ b/drivers/misc/sifive-otp.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This is a driver for the eMemory EG004K32TQ028XW01 NeoFuse
+ * One-Time-Programmable (OTP) memory used within the SiFive FU540.
+ * It is documented in the FU540 manual here:
+ * https://www.sifive.com/documentation/chips/freedom-u540-c000-manual/
+ *
+ * Copyright (C) 2018 Philipp Hug <philipp at hug.cx>
+ * Copyright (C) 2018 Joey Hewitt <joey at joeyhewitt.com>
+ *
+ * Copyright (C) 2020 SiFive, Inc
+ */
+
+/*
+ * The FU540 stores 4096x32 bit (16KiB) values.
+ * Index 0x00-0xff are reserved for SiFive internal use. (first 1KiB)
+ * Right now first 1KiB is used to store only serial number.
+ */
+
+#include <common.h>
+#include <dm/device.h>
+#include <dm/read.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <misc.h>
+
+#define BYTES_PER_FUSE		4
+
+#define PA_RESET_VAL		0x00
+#define PAS_RESET_VAL		0x00
+#define PAIO_RESET_VAL		0x00
+#define PDIN_RESET_VAL		0x00
+#define PTM_RESET_VAL		0x00
+
+#define PCLK_ENABLE_VAL			BIT(0)
+#define PCLK_DISABLE_VAL		0x00
+
+#define PWE_WRITE_ENABLE		BIT(0)
+#define PWE_WRITE_DISABLE		0x00
+
+#define PTM_FUSE_PROGRAM_VAL		BIT(1)
+
+#define PCE_ENABLE_INPUT		BIT(0)
+#define PCE_DISABLE_INPUT		0x00
+
+#define PPROG_ENABLE_INPUT		BIT(0)
+#define PPROG_DISABLE_INPUT		0x00
+
+#define PTRIM_ENABLE_INPUT		BIT(0)
+#define PTRIM_DISABLE_INPUT		0x00
+
+#define PDSTB_DEEP_STANDBY_ENABLE	BIT(0)
+#define PDSTB_DEEP_STANDBY_DISABLE	0x00
+
+/* Tpw - Program Pulse width delay */
+#define TPW_DELAY			20
+
+/* Tpwi - Program Pulse interval delay */
+#define TPWI_DELAY			5
+
+/* Tasp - Program address setup delay */
+#define TASP_DELAY			1
+
+/* Tcd - read data access delay */
+#define TCD_DELAY			40
+
+/* Tkl - clok pulse low delay */
+#define TKL_DELAY			10
+
+/* Tms - PTM mode setup delay */
+#define TMS_DELAY			1
+
+struct sifive_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) */
+};
+
+struct sifive_otp_platdata {
+	struct sifive_otp_regs __iomem *regs;
+	u32 total_fuses;
+};
+
+/*
+ * offset and size are assumed aligned to the size of the fuses (32-bit).
+ */
+static int sifive_otp_read(struct udevice *dev, int offset,
+			   void *buf, int size)
+{
+	struct sifive_otp_platdata *plat = dev_get_platdata(dev);
+	struct sifive_otp_regs *regs = (struct sifive_otp_regs *)plat->regs;
+
+	/* Check if offset and size are multiple of BYTES_PER_FUSE */
+	if ((size % BYTES_PER_FUSE) || (offset % BYTES_PER_FUSE)) {
+		printf("%s: size and offset must be multiple of 4.\n",
+		       __func__);
+		return -EINVAL;
+	}
+
+	int fuseidx = offset / BYTES_PER_FUSE;
+	int fusecount = size / BYTES_PER_FUSE;
+
+	/* check bounds */
+	if (offset < 0 || size < 0)
+		return -EINVAL;
+	if (fuseidx >= plat->total_fuses)
+		return -EINVAL;
+	if ((fuseidx + fusecount) > plat->total_fuses)
+		return -EINVAL;
+
+	u32 fusebuf[fusecount];
+
+	/* init OTP */
+	writel(PDSTB_DEEP_STANDBY_ENABLE, &regs->pdstb);
+	writel(PTRIM_ENABLE_INPUT, &regs->ptrim);
+	writel(PCE_ENABLE_INPUT, &regs->pce);
+
+	/* read all requested fuses */
+	for (unsigned int i = 0; i < fusecount; i++, fuseidx++) {
+		writel(fuseidx, &regs->pa);
+
+		/* cycle clock to read */
+		writel(PCLK_ENABLE_VAL, &regs->pclk);
+		ndelay(TCD_DELAY * 1000);
+		writel(PCLK_DISABLE_VAL, &regs->pclk);
+		ndelay(TKL_DELAY * 1000);
+
+		/* read the value */
+		fusebuf[i] = readl(&regs->pdout);
+	}
+
+	/* shut down */
+	writel(PCE_DISABLE_INPUT, &regs->pce);
+	writel(PTRIM_DISABLE_INPUT, &regs->ptrim);
+	writel(PDSTB_DEEP_STANDBY_DISABLE, &regs->pdstb);
+
+	/* copy out */
+	memcpy(buf, fusebuf, size);
+
+	return size;
+}
+
+/*
+ * Caution:
+ * OTP can be written only once, so use carefully.
+ *
+ * offset and size are assumed aligned to the size of the fuses (32-bit).
+ */
+static int sifive_otp_write(struct udevice *dev, int offset,
+			    const void *buf, int size)
+{
+	struct sifive_otp_platdata *plat = dev_get_platdata(dev);
+	struct sifive_otp_regs *regs = (struct sifive_otp_regs *)plat->regs;
+
+	/* Check if offset and size are multiple of BYTES_PER_FUSE */
+	if ((size % BYTES_PER_FUSE) || (offset % BYTES_PER_FUSE)) {
+		printf("%s: size and offset must be multiple of 4.\n",
+		       __func__);
+		return -EINVAL;
+	}
+
+	int fuseidx = offset / BYTES_PER_FUSE;
+	int fusecount = size / BYTES_PER_FUSE;
+	u32 *write_buf = (u32 *)buf;
+	u32 write_data;
+	int i, pas, bit;
+
+	/* check bounds */
+	if (offset < 0 || size < 0)
+		return -EINVAL;
+	if (fuseidx >= plat->total_fuses)
+		return -EINVAL;
+	if ((fuseidx + fusecount) > plat->total_fuses)
+		return -EINVAL;
+
+	/* init OTP */
+	writel(PDSTB_DEEP_STANDBY_ENABLE, &regs->pdstb);
+	writel(PTRIM_ENABLE_INPUT, &regs->ptrim);
+
+	/* reset registers */
+	writel(PCLK_DISABLE_VAL, &regs->pclk);
+	writel(PA_RESET_VAL, &regs->pa);
+	writel(PAS_RESET_VAL, &regs->pas);
+	writel(PAIO_RESET_VAL, &regs->paio);
+	writel(PDIN_RESET_VAL, &regs->pdin);
+	writel(PWE_WRITE_DISABLE, &regs->pwe);
+	writel(PTM_FUSE_PROGRAM_VAL, &regs->ptm);
+	ndelay(TMS_DELAY * 1000);
+
+	writel(PCE_ENABLE_INPUT, &regs->pce);
+	writel(PPROG_ENABLE_INPUT, &regs->pprog);
+
+	/* write all requested fuses */
+	for (i = 0; i < fusecount; i++, fuseidx++) {
+		writel(fuseidx, &regs->pa);
+		write_data = *(write_buf++);
+
+		for (pas = 0; pas < 2; pas++) {
+			writel(pas, &regs->pas);
+
+			for (bit = 0; bit < 32; bit++) {
+				writel(bit, &regs->paio);
+				writel(((write_data >> bit) & 1),
+				       &regs->pdin);
+				ndelay(TASP_DELAY * 1000);
+
+				writel(PWE_WRITE_ENABLE, &regs->pwe);
+				udelay(TPW_DELAY);
+				writel(PWE_WRITE_DISABLE, &regs->pwe);
+				udelay(TPWI_DELAY);
+			}
+		}
+
+		writel(PAS_RESET_VAL, &regs->pas);
+	}
+
+	/* shut down */
+	writel(PWE_WRITE_DISABLE, &regs->pwe);
+	writel(PPROG_DISABLE_INPUT, &regs->pprog);
+	writel(PCE_DISABLE_INPUT, &regs->pce);
+	writel(PTM_RESET_VAL, &regs->ptm);
+
+	writel(PTRIM_DISABLE_INPUT, &regs->ptrim);
+	writel(PDSTB_DEEP_STANDBY_DISABLE, &regs->pdstb);
+
+	return size;
+}
+
+static int sifive_otp_ofdata_to_platdata(struct udevice *dev)
+{
+	struct sifive_otp_platdata *plat = dev_get_platdata(dev);
+	int ret;
+
+	plat->regs = dev_read_addr_ptr(dev);
+
+	ret = dev_read_u32(dev, "fuse-count", &plat->total_fuses);
+	if (ret < 0) {
+		pr_err("\"fuse-count\" not found\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct misc_ops sifive_otp_ops = {
+	.read = sifive_otp_read,
+	.write = sifive_otp_write,
+};
+
+static const struct udevice_id sifive_otp_ids[] = {
+	{ .compatible = "sifive,fu540-c000-otp" },
+	{}
+};
+
+U_BOOT_DRIVER(sifive_otp) = {
+	.name = "sifive_otp",
+	.id = UCLASS_MISC,
+	.of_match = sifive_otp_ids,
+	.ofdata_to_platdata = sifive_otp_ofdata_to_platdata,
+	.platdata_auto_alloc_size = sizeof(struct sifive_otp_platdata),
+	.ops = &sifive_otp_ops,
+};
-- 
2.17.1