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hwrng: iproc-rng200: Add BCM2838 support

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The HWRNG on the BCM2838 is compatible to iproc-rng200, so add the
support to this driver instead of bcm2835-rng.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>

hwrng: iproc-rng200: Correct SoC name

The Pi 4 SoC is called BCM2711, not BCM2838.

Fixes: "hwrng: iproc-rng200: Add BCM2838 support"

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
This commit is contained in:
Stefan Wahren
2019-05-04 17:06:15 +02:00
committed by Dom Cobley
parent 71832f9ba8
commit 11eb112df6
2 changed files with 77 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/char/hw_random/Kconfig
View File

@@ -131,7 +131,7 @@ config HW_RANDOM_IPROC_RNG200
default HW_RANDOM
help
This driver provides kernel-side support for the RNG200
hardware found on the Broadcom iProc and STB SoCs.
hardware found on the Broadcom iProc, BCM2711 and STB SoCs.
To compile this driver as a module, choose M here: the
module will be called iproc-rng200

79
drivers/char/hw_random/iproc-rng200.c
View File

@@ -13,6 +13,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
@@ -20,6 +21,7 @@
#define RNG_CTRL_OFFSET 0x00
#define RNG_CTRL_RNG_RBGEN_MASK 0x00001FFF
#define RNG_CTRL_RNG_RBGEN_ENABLE 0x00000001
#define RNG_CTRL_RNG_DIV_CTRL_SHIFT 13
#define RNG_SOFT_RESET_OFFSET 0x04
#define RNG_SOFT_RESET 0x00000001
@@ -27,16 +29,23 @@
#define RBG_SOFT_RESET_OFFSET 0x08
#define RBG_SOFT_RESET 0x00000001
#define RNG_TOTAL_BIT_COUNT_OFFSET 0x0C
#define RNG_TOTAL_BIT_COUNT_THRESHOLD_OFFSET 0x10
#define RNG_INT_STATUS_OFFSET 0x18
#define RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK 0x80000000
#define RNG_INT_STATUS_STARTUP_TRANSITIONS_MET_IRQ_MASK 0x00020000
#define RNG_INT_STATUS_NIST_FAIL_IRQ_MASK 0x00000020
#define RNG_INT_STATUS_TOTAL_BITS_COUNT_IRQ_MASK 0x00000001
#define RNG_INT_ENABLE_OFFSET 0x1C
#define RNG_FIFO_DATA_OFFSET 0x20
#define RNG_FIFO_COUNT_OFFSET 0x24
#define RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK 0x000000FF
#define RNG_FIFO_COUNT_RNG_FIFO_THRESHOLD_SHIFT 8
struct iproc_rng200_dev {
struct hwrng rng;
@@ -157,6 +166,64 @@ static int iproc_rng200_init(struct hwrng *rng)
return 0;
}
static int bcm2711_rng200_read(struct hwrng *rng, void *buf, size_t max,
bool wait)
{
struct iproc_rng200_dev *priv = to_rng_priv(rng);
u32 max_words = max / sizeof(u32);
u32 num_words, count, val;
/* ensure warm up period has elapsed */
while (1) {
val = ioread32(priv->base + RNG_TOTAL_BIT_COUNT_OFFSET);
if (val > 16)
break;
cpu_relax();
}
/* ensure fifo is not empty */
while (1) {
num_words = ioread32(priv->base + RNG_FIFO_COUNT_OFFSET) &
RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK;
if (num_words)
break;
if (!wait)
return 0;
cpu_relax();
}
if (num_words > max_words)
num_words = max_words;
for (count = 0; count < num_words; count++) {
((u32 *)buf)[count] = ioread32(priv->base +
RNG_FIFO_DATA_OFFSET);
}
return num_words * sizeof(u32);
}
static int bcm2711_rng200_init(struct hwrng *rng)
{
struct iproc_rng200_dev *priv = to_rng_priv(rng);
uint32_t val;
if (ioread32(priv->base + RNG_CTRL_OFFSET) & RNG_CTRL_RNG_RBGEN_MASK)
return 0;
/* initial numbers generated are "less random" so will be discarded */
val = 0x40000;
iowrite32(val, priv->base + RNG_TOTAL_BIT_COUNT_THRESHOLD_OFFSET);
/* min fifo count to generate full interrupt */
val = 2 << RNG_FIFO_COUNT_RNG_FIFO_THRESHOLD_SHIFT;
iowrite32(val, priv->base + RNG_FIFO_COUNT_OFFSET);
/* enable the rng - 1Mhz sample rate */
val = (0x3 << RNG_CTRL_RNG_DIV_CTRL_SHIFT) | RNG_CTRL_RNG_RBGEN_MASK;
iowrite32(val, priv->base + RNG_CTRL_OFFSET);
return 0;
}
static void iproc_rng200_cleanup(struct hwrng *rng)
{
struct iproc_rng200_dev *priv = to_rng_priv(rng);
@@ -183,11 +250,17 @@ static int iproc_rng200_probe(struct platform_device *pdev)
dev_set_drvdata(dev, priv);
priv->rng.name = "iproc-rng200";
priv->rng.read = iproc_rng200_read;
priv->rng.init = iproc_rng200_init;
priv->rng.name = pdev->name;
priv->rng.cleanup = iproc_rng200_cleanup;
if (of_device_is_compatible(dev->of_node, "brcm,bcm2711-rng200")) {
priv->rng.init = bcm2711_rng200_init;
priv->rng.read = bcm2711_rng200_read;
} else {
priv->rng.init = iproc_rng200_init;
priv->rng.read = iproc_rng200_read;
}
/* Register driver */
ret = devm_hwrng_register(dev, &priv->rng);
if (ret) {