From: Stephen Warren <swarren@xxxxxxxxxx>
Various fuses on Tegra include information that's unique to an individual
chip, or a subset of chips. Call add_device_randomness() with this data
to perturb the initial state of the random pool.
Suggested-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx>
---
arch/arm/mach-tegra/fuse.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 54 insertions(+)
diff --git a/arch/arm/mach-tegra/fuse.c b/arch/arm/mach-tegra/fuse.c
index fef1dc8..9a4e910 100644
--- a/arch/arm/mach-tegra/fuse.c
+++ b/arch/arm/mach-tegra/fuse.c
@@ -21,14 +21,26 @@
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/export.h>
+#include <linux/random.h>
#include <linux/tegra-soc.h>
#include "fuse.h"
#include "iomap.h"
#include "apbio.h"
+/* Tegra20 only */
#define FUSE_UID_LOW 0x108
#define FUSE_UID_HIGH 0x10c
+
+/* Tegra30 and later */
+#define FUSE_VENDOR_CODE 0x200
+#define FUSE_FAB_CODE 0x204
+#define FUSE_LOT_CODE_0 0x208
+#define FUSE_LOT_CODE_1 0x20c
+#define FUSE_WAFER_ID 0x210
+#define FUSE_X_COORDINATE 0x214
+#define FUSE_Y_COORDINATE 0x218
+
#define FUSE_SKU_INFO 0x110
#define TEGRA20_FUSE_SPARE_BIT 0x200
@@ -112,21 +124,51 @@ u32 tegra_read_chipid(void)
return readl_relaxed(IO_ADDRESS(TEGRA_APB_MISC_BASE) + 0x804);
}
+static void __init tegra20_fuse_init_randomness(void)
+{
+ u32 randomness[2];
+
+ randomness[0] = tegra_fuse_readl(FUSE_UID_LOW);
+ randomness[1] = tegra_fuse_readl(FUSE_UID_HIGH);
+
+ add_device_randomness(randomness, sizeof(randomness));
+}
+
+/* Applies to Tegra30 or later */
+static void __init tegra30_fuse_init_randomness(void)
+{
+ u32 randomness[7];
+
+ randomness[0] = tegra_fuse_readl(FUSE_VENDOR_CODE);
+ randomness[1] = tegra_fuse_readl(FUSE_FAB_CODE);
+ randomness[2] = tegra_fuse_readl(FUSE_LOT_CODE_0);
+ randomness[3] = tegra_fuse_readl(FUSE_LOT_CODE_1);
+ randomness[4] = tegra_fuse_readl(FUSE_WAFER_ID);
+ randomness[5] = tegra_fuse_readl(FUSE_X_COORDINATE);
+ randomness[6] = tegra_fuse_readl(FUSE_Y_COORDINATE);
+
+ add_device_randomness(randomness, sizeof(randomness));
+}
+
void __init tegra_init_fuse(void)
{
u32 id;
+ u32 randomness[5];
u32 reg = readl(IO_ADDRESS(TEGRA_CLK_RESET_BASE + 0x48));
reg |= 1 << 28;
writel(reg, IO_ADDRESS(TEGRA_CLK_RESET_BASE + 0x48));
reg = tegra_fuse_readl(FUSE_SKU_INFO);
+ randomness[0] = reg;
tegra_sku_id = reg & 0xFF;
reg = tegra_apb_readl(TEGRA_APB_MISC_BASE + STRAP_OPT);
+ randomness[1] = reg;
tegra_bct_strapping = (reg & RAM_ID_MASK) >> RAM_CODE_SHIFT;
id = tegra_read_chipid();
+ randomness[2] = id;
tegra_chip_id = (id >> 8) & 0xff;
switch (tegra_chip_id) {
@@ -149,6 +191,18 @@ void __init tegra_init_fuse(void)
tegra_revision = tegra_get_revision(id);
tegra_init_speedo_data();
+ randomness[3] = (tegra_cpu_process_id << 16) | tegra_core_process_id;
+ randomness[4] = (tegra_cpu_speedo_id << 16) | tegra_soc_speedo_id;
+
+ add_device_randomness(randomness, sizeof(randomness));
+ switch (tegra_chip_id) {
+ case TEGRA20:
+ tegra20_fuse_init_randomness();
+ case TEGRA30:
+ case TEGRA114:
+ default:
+ tegra30_fuse_init_randomness();
+ }
pr_info("Tegra Revision: %s SKU: %d CPU Process: %d Core Process: %d\n",
tegra_revision_name[tegra_revision],
--
1.8.1.5
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