openwrt/target/linux/bcm27xx/patches-6.1/950-0606-hwrng-bcm2835-sleep-more-intelligently.patch
John Audia 2b75f108fb kernel: bump 6.1 to 6.1.63
Changelog: https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.1.63

Removed upstreamed:
	generic/backport-6.1/815-v6.6-2-leds-turris-omnia-Drop-unnecessary-mutex-locking.patch
	generic/backport-6.1/815-v6.7-1-leds-turris-omnia-Do-not-use-SMBUS-calls.patch
	ixp4xx/patches-6.1/0007-watchdog-ixp4xx-Make-sure-restart-always-works.patch

Manually rebased:
	bcm27xx/patches-6.1/950-0606-hwrng-bcm2835-sleep-more-intelligently.patch

All other patches automatically rebased.

1. https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.1.63&id=7d0e60e4ff840e97fb18afb2a7344442c10a6fdf
2. https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.1.63&id=63cdeb20ee3bfef820b045b8d3b8395f9f815a74
3. https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.1.63&id=8803da01fe1b4ca3d37745283f7e73c6c2558c0c

Build system: x86/64
Build-tested: x86/64/AMD Cezanne
Run-tested: x86/64/AMD Cezanne

Signed-off-by: John Audia <therealgraysky@proton.me>
2023-11-23 22:51:52 +01:00

67 lines
1.9 KiB
Diff

From 3537a855e3858b1f8b6cee545a22b8b67037235c Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Wed, 22 Mar 2023 15:30:38 +0000
Subject: [PATCH] hwrng: bcm2835 - sleep more intelligently
While waiting for random data, use sleeps that are proportional
to the amount of data expected. Prevent indefinite waits by
giving up if nothing is received for a second.
See: https://github.com/raspberrypi/linux/issues/5390
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/char/hw_random/bcm2835-rng.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
--- a/drivers/char/hw_random/bcm2835-rng.c
+++ b/drivers/char/hw_random/bcm2835-rng.c
@@ -14,6 +14,7 @@
#include <linux/printk.h>
#include <linux/clk.h>
#include <linux/reset.h>
+#include <linux/delay.h>
#define RNG_CTRL 0x0
#define RNG_STATUS 0x4
@@ -28,6 +29,9 @@
#define RNG_INT_OFF 0x1
+#define RNG_FIFO_WORDS 4
+#define RNG_US_PER_WORD 34 /* Tuned for throughput */
+
struct bcm2835_rng_priv {
struct hwrng rng;
void __iomem *base;
@@ -64,19 +68,23 @@ static inline void rng_writel(struct bcm
static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max,
bool wait)
{
+ u32 retries = 1000000/(RNG_FIFO_WORDS * RNG_US_PER_WORD);
struct bcm2835_rng_priv *priv = to_rng_priv(rng);
u32 max_words = max / sizeof(u32);
u32 num_words, count;
- while ((rng_readl(priv, RNG_STATUS) >> 24) == 0) {
- if (!wait)
+ num_words = rng_readl(priv, RNG_STATUS) >> 24;
+
+ while (!num_words) {
+ if (!wait || !retries)
return 0;
- hwrng_yield(rng);
+ retries--;
+ usleep_range((u32)RNG_US_PER_WORD,
+ (u32)RNG_US_PER_WORD * RNG_FIFO_WORDS);
+ num_words = rng_readl(priv, RNG_STATUS) >> 24;
}
- num_words = rng_readl(priv, RNG_STATUS) >> 24;
- if (num_words > max_words)
- num_words = max_words;
+ num_words = min(num_words, max_words);
for (count = 0; count < num_words; count++)
((u32 *)buf)[count] = rng_readl(priv, RNG_DATA);