On 7/10/19 10:28 PM, Anup Patel wrote:
-----Original Message-----
From: Troy Benjegerdes <troy.benjeger...@sifive.com>
Sent: Wednesday, July 10, 2019 10:45 PM
To: Anup Patel <anup.pa...@wdc.com>; Sagar Karandikar
<sagar.karandi...@sifive.com>; Joey Hewitt <j...@joeyhewitt.com>
Cc: Rick Chen <r...@andestech.com>; Bin Meng <bmeng...@gmail.com>;
Lukas Auer <lukas.a...@aisec.fraunhofer.de>; Simon Glass
<s...@chromium.org>; Ramon Fried <rfried....@gmail.com>; Joe
Hershberger <joe.hershber...@ni.com>; Palmer Dabbelt
<pal...@sifive.com>; Paul Walmsley <paul.walms...@sifive.com>; Atish
Patra <atish.pa...@wdc.com>; Alistair Francis <alistair.fran...@wdc.com>;
U-Boot Mailing List <u-boot@lists.denx.de>
Subject: Re: [PATCH v7 7/9] riscv: sifive: fu540: Setup ethaddr env variable
using OTP
On Jun 23, 2019, at 11:03 PM, Anup Patel <anup.pa...@wdc.com> wrote:
This patch extends SiFive FU540 board support to setup ethaddr env
variable based on board serialnum read from OTP.
Signed-off-by: Anup Patel <anup.pa...@wdc.com>
---
board/sifive/fu540/fu540.c | 122
+++++++++++++++++++++++++++++++++
configs/sifive_fu540_defconfig | 1 +
2 files changed, 123 insertions(+)
diff --git a/board/sifive/fu540/fu540.c b/board/sifive/fu540/fu540.c
index 5adc4a3d4a..11daf1a75a 100644
--- a/board/sifive/fu540/fu540.c
+++ b/board/sifive/fu540/fu540.c
@@ -8,6 +8,128 @@
#include <common.h>
#include <dm.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+
+#ifdef CONFIG_MISC_INIT_R
+
+#define FU540_OTP_BASE_ADDR 0x10070000
+
+struct fu540_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) */
+} __packed;
+
+#define BYTES_PER_FUSE 4
+#define NUM_FUSES 0x1000
+
+static int fu540_otp_read(int offset, void *buf, int size) {
+ struct fu540_otp_regs *regs = (void __iomem
*)FU540_OTP_BASE_ADDR;
+ unsigned int i;
+ int fuseidx = offset / BYTES_PER_FUSE;
+ int fusecount = size / BYTES_PER_FUSE;
+ u32 fusebuf[fusecount];
+
+ /* check bounds */
+ if (offset < 0 || size < 0)
+ return -EINVAL;
+ if (fuseidx >= NUM_FUSES)
+ return -EINVAL;
+ if ((fuseidx + fusecount) > NUM_FUSES)
+ return -EINVAL;
+
+ /* init OTP */
+ writel(0x01, ®s->pdstb); /* wake up from stand-by */
+ writel(0x01, ®s->ptrim); /* enable repair function */
+ writel(0x01, ®s->pce); /* enable input */
+
+ /* read all requested fuses */
+ for (i = 0; i < fusecount; i++, fuseidx++) {
+ writel(fuseidx, ®s->pa);
+
+ /* cycle clock to read */
+ writel(0x01, ®s->pclk);
+ mdelay(1);
+ writel(0x00, ®s->pclk);
+ mdelay(1);
+
+ /* read the value */
+ fusebuf[i] = readl(®s->pdout);
+ }
+
+ /* shut down */
+ writel(0, ®s->pce);
+ writel(0, ®s->ptrim);
+ writel(0, ®s->pdstb);
+
+ /* copy out */
+ memcpy(buf, fusebuf, size);
+
+ return 0;
+}
+
+static u32 fu540_read_serialnum(void) {
+ int ret;
+ u32 serial[2] = {0};
+
+ for (int i = 0xfe * 4; i > 0; i -= 8) {
+ ret = fu540_otp_read(i, serial, sizeof(serial));
+ if (ret) {
+ printf("%s: error reading from OTP\n", __func__);
+ break;
+ }
+ if (serial[0] == ~serial[1])
+ return serial[0];
+ }
+
+ return 0;
+}
Please take a look at the DM-enabled SiFive OTP driver submitted by Joey
Hewitt at https://github.com/sifive/HiFive_U-
Boot/commit/6d842765de142b61f847852da7a9ce0d081d770c
This Joey's version also sets the ‘serial#’ environment variable, while this
patch only sets ‘ethaddr'
I am not sure if "serial#" environment variable is a standard U-Boot
way of advertising serial number of underlying Host.
Where is this used?
Regards,
Anup
The serial# var is inserted into the device tree.
https://github.com/u-boot/u-boot/blob/0de815356474912ef5bef9a69f0327a5a93bb2c2/common/fdt_support.c#L199
See also
https://github.com/torvalds/linux/commit/13dd92bb4599b5655cafe1f2c0365396a096b94a
I don't recall if it had any particularly special meaning on the kernels
I tested with, but it seems to be standard and could be useful to userspace.
-Joey
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