@@ -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
@@ -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
new file mode 100644
@@ -0,0 +1,273 @@
+// 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@hug.cx>
+ * Copyright (C) 2018 Joey Hewitt <joey@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/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, ®s->pdstb);
+ writel(PTRIM_ENABLE_INPUT, ®s->ptrim);
+ writel(PCE_ENABLE_INPUT, ®s->pce);
+
+ /* read all requested fuses */
+ for (unsigned int i = 0; i < fusecount; i++, fuseidx++) {
+ writel(fuseidx, ®s->pa);
+
+ /* cycle clock to read */
+ writel(PCLK_ENABLE_VAL, ®s->pclk);
+ ndelay(TCD_DELAY * 1000);
+ writel(PCLK_DISABLE_VAL, ®s->pclk);
+ ndelay(TKL_DELAY * 1000);
+
+ /* read the value */
+ fusebuf[i] = readl(®s->pdout);
+ }
+
+ /* shut down */
+ writel(PCE_DISABLE_INPUT, ®s->pce);
+ writel(PTRIM_DISABLE_INPUT, ®s->ptrim);
+ writel(PDSTB_DEEP_STANDBY_DISABLE, ®s->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, ®s->pdstb);
+ writel(PTRIM_ENABLE_INPUT, ®s->ptrim);
+
+ /* reset registers */
+ writel(PCLK_DISABLE_VAL, ®s->pclk);
+ writel(PA_RESET_VAL, ®s->pa);
+ writel(PAS_RESET_VAL, ®s->pas);
+ writel(PAIO_RESET_VAL, ®s->paio);
+ writel(PDIN_RESET_VAL, ®s->pdin);
+ writel(PWE_WRITE_DISABLE, ®s->pwe);
+ writel(PTM_FUSE_PROGRAM_VAL, ®s->ptm);
+ ndelay(TMS_DELAY * 1000);
+
+ writel(PCE_ENABLE_INPUT, ®s->pce);
+ writel(PPROG_ENABLE_INPUT, ®s->pprog);
+
+ /* write all requested fuses */
+ for (i = 0; i < fusecount; i++, fuseidx++) {
+ writel(fuseidx, ®s->pa);
+ write_data = *(write_buf++);
+
+ for (pas = 0; pas < 2; pas++) {
+ writel(pas, ®s->pas);
+
+ for (bit = 0; bit < 32; bit++) {
+ writel(bit, ®s->paio);
+ writel(((write_data >> bit) & 1),
+ ®s->pdin);
+ ndelay(TASP_DELAY * 1000);
+
+ writel(PWE_WRITE_ENABLE, ®s->pwe);
+ udelay(TPW_DELAY);
+ writel(PWE_WRITE_DISABLE, ®s->pwe);
+ udelay(TPWI_DELAY);
+ }
+ }
+
+ writel(PAS_RESET_VAL, ®s->pas);
+ }
+
+ /* shut down */
+ writel(PWE_WRITE_DISABLE, ®s->pwe);
+ writel(PPROG_DISABLE_INPUT, ®s->pprog);
+ writel(PCE_DISABLE_INPUT, ®s->pce);
+ writel(PTM_RESET_VAL, ®s->ptm);
+
+ writel(PTRIM_DISABLE_INPUT, ®s->ptrim);
+ writel(PDSTB_DEEP_STANDBY_DISABLE, ®s->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,
+};