From: "Neil Armstrong" <neil.armstrong@linaro.org>
To: Alexey Romanov <avromanov@sberdevices.ru>,
narmstrong@baylibre.com, xypron.glpk@gmx.de,
sughosh.ganu@linaro.org
Cc: u-boot-amlogic@groups.io, u-boot@lists.denx.de, kernel@sberdevices.ru
Subject: Re: [PATCH v1] drivers: rng: add check status bit feature
Date: Thu, 22 Jun 2023 18:18:28 +0200 [thread overview]
Message-ID: <697a4d8a-0a1b-16cb-a5dd-f1e25d11d4f9@linaro.org> (raw)
In-Reply-To: <20230621102401.76646-1-avromanov@sberdevices.ru>
Hi,
On 21/06/2023 12:24, Alexey Romanov wrote:
> For some Amlogic SOC's, the mechanism for obtain a random number
> has been changed. For example, S4 now uses a status bit wait algo.
Thanks for the change, but could you add this first in Linux with the
associated bindings update and DT changes then port it to U-boot ?
Thanks,
Neil
>
> Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
> ---
> drivers/rng/meson-rng.c | 73 +++++++++++++++++++++++++++++++++++++----
> 1 file changed, 67 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/rng/meson-rng.c b/drivers/rng/meson-rng.c
> index e0a1e8c7e04..3bf2eb9cf87 100644
> --- a/drivers/rng/meson-rng.c
> +++ b/drivers/rng/meson-rng.c
> @@ -11,36 +11,82 @@
> #include <rng.h>
> #include <asm/io.h>
>
> +struct meson_rng_data {
> + bool check_status_bit;
> +};
> +
> struct meson_rng_plat {
> fdt_addr_t base;
> struct clk clk;
> + struct meson_rng_data *data;
> };
>
> +#define RETRY_CNT 100
> +#define RNG_OUT_OFFSET 0x08
> +
> +#define SEED_READY_STS_BIT 0
> +#define RUN_BIT 31
> +
> +static int meson_rng_wait_status(struct meson_rng_plat *pdata, int bit)
> +{
> + u32 status;
> + u32 cnt = 0;
> +
> + pr_debug("Poll status of bit: %d\n", bit);
> +
> + do {
> + status = readl(pdata->base) & BIT(bit);
> + } while (status && (cnt++ < RETRY_CNT));
> +
> + if (cnt == RETRY_CNT) {
> + pr_err("Can't get random number, try again");
> + return -EBUSY;
> + }
> +
> + return 0;
> +}
> +
> /**
> * meson_rng_read() - fill buffer with random bytes
> *
> * @buffer: buffer to receive data
> * @size: size of buffer
> *
> - * Return: 0
> + * Return: 0 on success or -errno in failure
> */
> static int meson_rng_read(struct udevice *dev, void *data, size_t len)
> {
> struct meson_rng_plat *pdata = dev_get_plat(dev);
> + struct meson_rng_data *rng_data = pdata->data;
> char *buffer = (char *)data;
> + int err;
>
> while (len) {
> - u32 rand = readl(pdata->base);
> + u32 rand;
> size_t step;
>
> - if (len >= 4)
> - step = 4;
> - else
> - step = len;
> + if (rng_data->check_status_bit) {
> + writel(readl(pdata->base) | BIT(SEED_READY_STS_BIT), pdata->base);
> +
> + err = meson_rng_wait_status(pdata, SEED_READY_STS_BIT);
> + if (err)
> + return err;
> +
> + err = meson_rng_wait_status(pdata, RUN_BIT);
> + if (err)
> + return err;
> +
> + rand = readl(pdata->base + RNG_OUT_OFFSET);
> + } else {
> + rand = readl(pdata->base);
> + }
> +
> + step = min_t(u32, len, 4);
> memcpy(buffer, &rand, step);
> buffer += step;
> len -= step;
> }
> +
> return 0;
> }
>
> @@ -90,6 +136,8 @@ static int meson_rng_of_to_plat(struct udevice *dev)
> if (!pdata->base)
> return -ENODEV;
>
> + pdata->data = (struct meson_rng_data *)dev_get_driver_data(dev);
> +
> /* Get optional "core" clock */
> err = clk_get_by_name_optional(dev, "core", &pdata->clk);
> if (err)
> @@ -102,9 +150,22 @@ static const struct dm_rng_ops meson_rng_ops = {
> .read = meson_rng_read,
> };
>
> +static const struct meson_rng_data meson_rng_data = {
> + .check_status_bit = false,
> +};
> +
> +static const struct meson_rng_data meson_rng_data_s4 = {
> + .check_status_bit = true,
> +};
> +
> static const struct udevice_id meson_rng_match[] = {
> {
> .compatible = "amlogic,meson-rng",
> + .data = (ulong)&meson_rng_data,
> + },
> + {
> + .compatible = "amlogic,meson-rng-s4",
> + .data = (ulong)&meson_rng_data_s4,
> },
> {},
> };
parent reply other threads:[~2023-06-22 16:18 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20230621102401.76646-1-avromanov@sberdevices.ru>]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=697a4d8a-0a1b-16cb-a5dd-f1e25d11d4f9@linaro.org \
--to=neil.armstrong@linaro.org \
--cc=avromanov@sberdevices.ru \
--cc=kernel@sberdevices.ru \
--cc=narmstrong@baylibre.com \
--cc=sughosh.ganu@linaro.org \
--cc=u-boot-amlogic@groups.io \
--cc=u-boot@lists.denx.de \
--cc=xypron.glpk@gmx.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).