| /* SPDX-License-Identifier: GPL-2.0-only */ |
| |
| #include <stddef.h> |
| #include <delay.h> |
| #include <device/mmio.h> |
| #include <console/console.h> |
| #include <console/uart.h> |
| #include <soc/addressmap.h> |
| #include <soc/otp.h> |
| |
| /* |
| * 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/ |
| */ |
| |
| struct sifive_otp_registers { |
| 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; |
| |
| /* |
| * Read a 32 bit value addressed by its index from the OTP. |
| * The FU540 stores 4096x32 bit (16KiB) values. |
| * Index 0x00-0xff are reserved for SiFive internal use. (first 1KiB) |
| */ |
| |
| u32 otp_read_word(u16 idx) |
| { |
| u32 w; |
| |
| if (idx >= 0x1000) |
| die("otp: idx out of bounds"); |
| |
| struct sifive_otp_registers *regs = (void *)(FU540_OTP); |
| |
| // wake up from stand-by |
| write32(®s->pdstb, 0x01); |
| |
| // enable repair function |
| write32(®s->ptrim, 0x01); |
| |
| // enable input |
| write32(®s->pce, 0x01); |
| |
| // address to read |
| write32(®s->pa, idx); |
| |
| // cycle clock to read |
| write32(®s->pclk, 0x01); |
| mdelay(1); |
| |
| write32(®s->pclk, 0x00); |
| mdelay(1); |
| |
| w = read32(®s->pdout); |
| |
| // shut down |
| write32(®s->pce, 0x00); |
| write32(®s->ptrim, 0x00); |
| write32(®s->pdstb, 0x00); |
| |
| return w; |
| } |
| |
| u32 otp_read_serial(void) |
| { |
| u32 serial = 0; |
| u32 serial_n = 0; |
| for (int i = 0xfe; i > 0; i -= 2) { |
| serial = otp_read_word(i); |
| serial_n = otp_read_word(i+1); |
| if (serial == ~serial_n) |
| break; |
| } |
| return serial; |
| } |