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![Philipp Tomsich](/assets/img/avatar_default.png)
This adds a simple driver for reading the efuse block of the RK3399. It should be easy enough to add drivers for other devices (e.g. the RK3328, RK3368, etc.) by passing the device details via driver_data. Unlike the kernel driver (using the nvmem subsystem), we don't expose the efuse as multiple named cells, but rather as a linear memory that can be read using misc_read(...). The primary use case (as of today) is the generation of a 'serial#' (and a 'cpuid#') environment variable for the RK3399-Q7 (Puma) system-on-module. Note that this adds a debug-only (i.e. only if DEBUG is defined) command 'rk3399_dump_efuses' that dumps the efuse block's content. N.B.: The name 'rk3399_dump_efuses' was intentionally chosen to include a SoC-name (together with a comment in the function) to remind whoever adds support for additional SoCs that this function currently makes assumptions regarding the size of the fuse-box based on the RK3399. The hope is that the function is adjusted to reflect any changes resulting from generalising the driver for multiple SoCs and is then renamed. Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com> Reviewed-by: Simon Glass <sjg@chromium.org>
162 lines
4.0 KiB
C
162 lines
4.0 KiB
C
/*
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* eFuse driver for Rockchip devices
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*
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* Copyright 2017, Theobroma Systems Design und Consulting GmbH
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* Written by Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <asm/io.h>
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#include <command.h>
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#include <display_options.h>
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#include <dm.h>
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#include <linux/bitops.h>
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#include <linux/delay.h>
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#include <misc.h>
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#define RK3399_A_SHIFT 16
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#define RK3399_A_MASK 0x3ff
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#define RK3399_NFUSES 32
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#define RK3399_BYTES_PER_FUSE 4
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#define RK3399_STROBSFTSEL BIT(9)
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#define RK3399_RSB BIT(7)
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#define RK3399_PD BIT(5)
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#define RK3399_PGENB BIT(3)
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#define RK3399_LOAD BIT(2)
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#define RK3399_STROBE BIT(1)
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#define RK3399_CSB BIT(0)
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struct rockchip_efuse_regs {
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u32 ctrl; /* 0x00 efuse control register */
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u32 dout; /* 0x04 efuse data out register */
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u32 rf; /* 0x08 efuse redundancy bit used register */
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u32 _rsvd0;
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u32 jtag_pass; /* 0x10 JTAG password */
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u32 strobe_finish_ctrl;
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/* 0x14 efuse strobe finish control register */
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};
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struct rockchip_efuse_platdata {
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void __iomem *base;
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struct clk *clk;
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};
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#if defined(DEBUG)
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static int dump_efuses(cmd_tbl_t *cmdtp, int flag,
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int argc, char * const argv[])
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{
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/*
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* N.B.: This function is tailored towards the RK3399 and assumes that
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* there's always 32 fuses x 32 bits (i.e. 128 bytes of data) to
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* be read.
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*/
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struct udevice *dev;
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u8 fuses[128];
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int ret;
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/* retrieve the device */
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ret = uclass_get_device_by_driver(UCLASS_MISC,
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DM_GET_DRIVER(rockchip_efuse), &dev);
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if (ret) {
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printf("%s: no misc-device found\n", __func__);
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return 0;
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}
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ret = misc_read(dev, 0, &fuses, sizeof(fuses));
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if (ret) {
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printf("%s: misc_read failed\n", __func__);
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return 0;
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}
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printf("efuse-contents:\n");
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print_buffer(0, fuses, 1, 128, 16);
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return 0;
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}
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U_BOOT_CMD(
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rk3399_dump_efuses, 1, 1, dump_efuses,
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"Dump the content of the efuses",
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""
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);
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#endif
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static int rockchip_rk3399_efuse_read(struct udevice *dev, int offset,
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void *buf, int size)
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{
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struct rockchip_efuse_platdata *plat = dev_get_platdata(dev);
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struct rockchip_efuse_regs *efuse =
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(struct rockchip_efuse_regs *)plat->base;
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unsigned int addr_start, addr_end, addr_offset;
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u32 out_value;
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u8 bytes[RK3399_NFUSES * RK3399_BYTES_PER_FUSE];
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int i = 0;
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u32 addr;
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addr_start = offset / RK3399_BYTES_PER_FUSE;
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addr_offset = offset % RK3399_BYTES_PER_FUSE;
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addr_end = DIV_ROUND_UP(offset + size, RK3399_BYTES_PER_FUSE);
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/* cap to the size of the efuse block */
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if (addr_end > RK3399_NFUSES)
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addr_end = RK3399_NFUSES;
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writel(RK3399_LOAD | RK3399_PGENB | RK3399_STROBSFTSEL | RK3399_RSB,
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&efuse->ctrl);
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udelay(1);
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for (addr = addr_start; addr < addr_end; addr++) {
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setbits_le32(&efuse->ctrl,
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RK3399_STROBE | (addr << RK3399_A_SHIFT));
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udelay(1);
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out_value = readl(&efuse->dout);
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clrbits_le32(&efuse->ctrl, RK3399_STROBE);
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udelay(1);
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memcpy(&bytes[i], &out_value, RK3399_BYTES_PER_FUSE);
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i += RK3399_BYTES_PER_FUSE;
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}
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/* Switch to standby mode */
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writel(RK3399_PD | RK3399_CSB, &efuse->ctrl);
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memcpy(buf, bytes + addr_offset, size);
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return 0;
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}
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static int rockchip_efuse_read(struct udevice *dev, int offset,
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void *buf, int size)
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{
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return rockchip_rk3399_efuse_read(dev, offset, buf, size);
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}
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static const struct misc_ops rockchip_efuse_ops = {
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.read = rockchip_efuse_read,
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};
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static int rockchip_efuse_ofdata_to_platdata(struct udevice *dev)
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{
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struct rockchip_efuse_platdata *plat = dev_get_platdata(dev);
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plat->base = (void *)devfdt_get_addr(dev);
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return 0;
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}
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static const struct udevice_id rockchip_efuse_ids[] = {
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{ .compatible = "rockchip,rk3399-efuse" },
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{}
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};
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U_BOOT_DRIVER(rockchip_efuse) = {
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.name = "rockchip_efuse",
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.id = UCLASS_MISC,
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.of_match = rockchip_efuse_ids,
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.ofdata_to_platdata = rockchip_efuse_ofdata_to_platdata,
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.platdata_auto_alloc_size = sizeof(struct rockchip_efuse_platdata),
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.ops = &rockchip_efuse_ops,
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};
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