Re: [U-Boot] [PATCH v7 7/9] riscv: sifive: fu540: Setup ethaddr env variable using OTP

[Troy Benjegerdes]

> 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, &regs->pdstb); /* wake up from stand-by */
> +     writel(0x01, &regs->ptrim); /* enable repair function */
> +     writel(0x01, &regs->pce);   /* enable input */
> +
> +     /* read all requested fuses */
> +     for (i = 0; i < fusecount; i++, fuseidx++) {
> +             writel(fuseidx, &regs->pa);
> +
> +             /* cycle clock to read */
> +             writel(0x01, &regs->pclk);
> +             mdelay(1);
> +             writel(0x00, &regs->pclk);
> +             mdelay(1);
> +
> +             /* read the value */
> +             fusebuf[i] = readl(&regs->pdout);
> +     }
> +
> +     /* shut down */
> +     writel(0, &regs->pce);
> +     writel(0, &regs->ptrim);
> +     writel(0, &regs->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'

> +
> +static void fu540_setup_macaddr(u32 serialnum)
> +{
> +     /* Default MAC address */
> +     unsigned char mac[6] = { 0x70, 0xb3, 0xd5, 0x92, 0xf0, 0x00 };
> +
> +     /*
> +      * We derive our board MAC address by ORing last three bytes
> +      * of board serial number to above default MAC address.
> +      *
> +      * This logic of deriving board MAC address is taken from
> +      * SiFive FSBL and is kept unchanged.
> +      */
> +     mac[5] |= (serialnum >>  0) & 0xff;
> +     mac[4] |= (serialnum >>  8) & 0xff;
> +     mac[3] |= (serialnum >> 16) & 0xff;
> +
> +     /* Update environment variable */
> +     eth_env_set_enetaddr("ethaddr", mac);
> +}
> +
> +int misc_init_r(void)
> +{
> +     /* Set ethaddr environment variable if not set */
> +     if (!env_get("ethaddr"))
> +             fu540_setup_macaddr(fu540_read_serialnum());
> +
> +     return 0;
> +}
> +
> +#endif
> 
> int board_init(void)
> {
> diff --git a/configs/sifive_fu540_defconfig b/configs/sifive_fu540_defconfig
> index f78412398e..f19203745e 100644
> --- a/configs/sifive_fu540_defconfig
> +++ b/configs/sifive_fu540_defconfig
> @@ -7,4 +7,5 @@ CONFIG_DISTRO_DEFAULTS=y
> CONFIG_FIT=y
> CONFIG_DISPLAY_CPUINFO=y
> CONFIG_DISPLAY_BOARDINFO=y
> +CONFIG_MISC_INIT_R=y
> CONFIG_OF_PRIOR_STAGE=y
> -- 
> 2.17.1
> 

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