u-boot/drivers/misc/sifive-otp.c

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// 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/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_plat {
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_plat *plat = dev_get_plat(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_plat *plat = dev_get_plat(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_of_to_plat(struct udevice *dev)
{
struct sifive_otp_plat *plat = dev_get_plat(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,
.of_to_plat = sifive_otp_of_to_plat,
.plat_auto = sizeof(struct sifive_otp_plat),
.ops = &sifive_otp_ops,
};