[HWRNG 01/03]: move status polling loop to data_present callbacks

Patrick McHardy
2007-11-18T21:33:32Z

[HWRNG]: move status polling loop to data_present callbacks

Handle waiting for new random within the drivers themselves, this allows to
use better suited timeouts for the individual rngs.

Signed-off-by: Patrick McHardy <kaber@trash.net>

---
commit 5632554998aafc5605635f842bca50d5353cd9d4
tree 161324874febaf01d70ab2dd0b434db962108265
parent 92704884669e1af381feb364bc83985a63934c56
author Patrick McHardy <kaber@trash.net> Sun, 18 Nov 2007 22:09:05 +0100
committer Patrick McHardy <kaber@trash.net> Sun, 18 Nov 2007 22:09:05 +0100

drivers/char/hw_random/amd-rng.c | 12 ++++++++++--
drivers/char/hw_random/core.c | 24 ++++++------------------
drivers/char/hw_random/geode-rng.c | 12 ++++++++++--
drivers/char/hw_random/intel-rng.c | 15 ++++++++++++---
drivers/char/hw_random/omap-rng.c | 13 +++++++++++--
drivers/char/hw_random/pasemi-rng.c | 14 +++++++++++---
drivers/char/hw_random/via-rng.c | 19 ++++++++++++-------
include/linux/hw_random.h | 2 +-
8 files changed, 73 insertions(+), 38 deletions(-)

diff --git a/drivers/char/hw_random/amd-rng.c b/drivers/char/hw_random/amd-rng.c
index 556fd81..c422e87 100644
--- a/drivers/char/hw_random/amd-rng.c
+++ b/drivers/char/hw_random/amd-rng.c
@@ -28,6 +28,7 @@
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/hw_random.h>
+#include <linux/delay.h>
#include <asm/io.h>

@@ -52,11 +53,18 @@ MODULE_DEVICE_TABLE(pci, pci_tbl);
static struct pci_dev *amd_pdev;

-static int amd_rng_data_present(struct hwrng *rng)
+static int amd_rng_data_present(struct hwrng *rng, int wait)
{
u32 pmbase = (u32)rng->priv;
+ int data, i;

- return !!(inl(pmbase + 0xF4) & 1);
+ for (i = 0; i < 20; i++) {
+ data = !!(inl(pmbase + 0xF4) & 1);
+ if (data || !wait)
+ break;
+ udelay(10);
+ }
+ return data;
}

static int amd_rng_data_read(struct hwrng *rng, u32 *data)
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 26a860a..0118b98 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -66,11 +66,11 @@ static inline void hwrng_cleanup(struct hwrng *rng)
rng->cleanup(rng);
}

-static inline int hwrng_data_present(struct hwrng *rng)
+static inline int hwrng_data_present(struct hwrng *rng, int wait)
{
if (!rng->data_present)
return 1;
- return rng->data_present(rng);
+ return rng->data_present(rng, wait);
}

static inline int hwrng_data_read(struct hwrng *rng, u32 *data)
@@ -94,8 +94,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
{
u32 data;
ssize_t ret = 0;
- int i, err = 0;
- int data_present;
+ int err = 0;
int bytes_read;

while (size) {
@@ -107,21 +106,10 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
err = -ENODEV;
goto out;
}
- if (filp->f_flags & O_NONBLOCK) {
- data_present = hwrng_data_present(current_rng);
- } else {
- /* Some RNG require some time between data_reads to gather
- * new entropy. Poll it.
- */
- for (i = 0; i < 20; i++) {
- data_present = hwrng_data_present(current_rng);
- if (data_present)
- break;
- udelay(10);
- }
- }
+
bytes_read = 0;
- if (data_present)
+ if (hwrng_data_present(current_rng,
+ !(filp->f_flags & O_NONBLOCK)))
bytes_read = hwrng_data_read(current_rng, &data);
mutex_unlock(&rng_mutex);

diff --git a/drivers/char/hw_random/geode-rng.c b/drivers/char/hw_random/geode-rng.c
index 8e8658d..fed4ef5 100644
--- a/drivers/char/hw_random/geode-rng.c
+++ b/drivers/char/hw_random/geode-rng.c
@@ -28,6 +28,7 @@
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/hw_random.h>
+#include <linux/delay.h>
#include <asm/io.h>

@@ -61,11 +62,18 @@ static int geode_rng_data_read(struct hwrng *rng, u32 *data)
return 4;
}

-static int geode_rng_data_present(struct hwrng *rng)
+static int geode_rng_data_present(struct hwrng *rng, int wait)
{
void __iomem *mem = (void __iomem *)rng->priv;
+ int data, i;

- return !!(readl(mem + GEODE_RNG_STATUS_REG));
+ for (i = 0; i < 20; i++) {
+ data = !!(readl(mem + GEODE_RNG_STATUS_REG));
+ if (data || !wait)
+ break;
+ udelay(10);
+ }
+ return data;
}

diff --git a/drivers/char/hw_random/intel-rng.c b/drivers/char/hw_random/intel-rng.c
index 753f460..5cc651e 100644
--- a/drivers/char/hw_random/intel-rng.c
+++ b/drivers/char/hw_random/intel-rng.c
@@ -29,6 +29,7 @@
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/stop_machine.h>
+#include <linux/delay.h>
#include <asm/io.h>

@@ -162,11 +163,19 @@ static inline u8 hwstatus_set(void __iomem *mem,
return hwstatus_get(mem);
}

-static int intel_rng_data_present(struct hwrng *rng)
+static int intel_rng_data_present(struct hwrng *rng, int wait)
{
void __iomem *mem = (void __iomem *)rng->priv;
-
- return !!(readb(mem + INTEL_RNG_STATUS) & INTEL_RNG_DATA_PRESENT);
+ int data, i;
+
+ for (i = 0; i < 20; i++) {
+ data = !!(readb(mem + INTEL_RNG_STATUS) &
+ INTEL_RNG_DATA_PRESENT);
+ if (data || !wait)
+ break;
+ udelay(10);
+ }
+ return data;
}

static int intel_rng_data_read(struct hwrng *rng, u32 *data)
diff --git a/drivers/char/hw_random/omap-rng.c b/drivers/char/hw_random/omap-rng.c
index 3f35a1c..7e31995 100644
--- a/drivers/char/hw_random/omap-rng.c
+++ b/drivers/char/hw_random/omap-rng.c
@@ -29,6 +29,7 @@
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/hw_random.h>
+#include <linux/delay.h>

#include <asm/io.h>

@@ -65,9 +66,17 @@ static void omap_rng_write_reg(int reg, u32 val)
}

/* REVISIT: Does the status bit really work on 16xx? */
-static int omap_rng_data_present(struct hwrng *rng)
+static int omap_rng_data_present(struct hwrng *rng, int wait)
{
- return omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1;
+ int data, i;
+
+ for (i = 0; i < 20; i++) {
+ data = omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1;
+ if (data || !wait)
+ break;
+ udelay(10);
+ }
+ return data;
}

static int omap_rng_data_read(struct hwrng *rng, u32 *data)
diff --git a/drivers/char/hw_random/pasemi-rng.c b/drivers/char/hw_random/pasemi-rng.c
index fa6040b..621adf2 100644
--- a/drivers/char/hw_random/pasemi-rng.c
+++ b/drivers/char/hw_random/pasemi-rng.c
@@ -23,6 +23,7 @@
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/hw_random.h>
+#include <linux/delay.h>
#include <asm/of_platform.h>
#include <asm/io.h>

@@ -44,9 +45,16 @@
static int pasemi_rng_data_present(struct hwrng *rng)
{
void __iomem *rng_regs = (void __iomem *)rng->priv;
-
- return (in_le32(rng_regs + SDCRNG_CTL_REG)
- & SDCRNG_CTL_FVLD_M) ? 1 : 0;
+ int data, i;
+
+ for (i = 0; i < 20; i++) {
+ data = (in_le32(rng_regs + SDCRNG_CTL_REG)
+ & SDCRNG_CTL_FVLD_M) ? 1 : 0;
+ if (data || !wait)
+ break;
+ udelay(10);
+ }
+ return data;
}

static int pasemi_rng_data_read(struct hwrng *rng, u32 *data)
diff --git a/drivers/char/hw_random/via-rng.c b/drivers/char/hw_random/via-rng.c
index ec435cb..868e39f 100644
--- a/drivers/char/hw_random/via-rng.c
+++ b/drivers/char/hw_random/via-rng.c
@@ -27,6 +27,7 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/hw_random.h>
+#include <linux/delay.h>
#include <asm/io.h>
#include <asm/msr.h>
#include <asm/cpufeature.h>
@@ -77,10 +78,11 @@ static inline u32 xstore(u32 *addr, u32 edx_in)
return eax_out;
}

-static int via_rng_data_present(struct hwrng *rng)
+static int via_rng_data_present(struct hwrng *rng, int wait)
{
u32 bytes_out;
u32 *via_rng_datum = (u32 *)(&rng->priv);
+ int i;

/* We choose the recommended 1-byte-per-instruction RNG rate,
* for greater randomness at the expense of speed. Larger
@@ -95,12 +97,15 @@ static int via_rng_data_present(struct hwrng *rng)
* completes.
*/

- *via_rng_datum = 0; /* paranoia, not really necessary */
- bytes_out = xstore(via_rng_datum, VIA_RNG_CHUNK_1);
- bytes_out &= VIA_XSTORE_CNT_MASK;
- if (bytes_out == 0)
- return 0;
- return 1;
+ for (i = 0; i < 20; i++) {
+ *via_rng_datum = 0; /* paranoia, not really necessary */
+ bytes_out = xstore(via_rng_datum, VIA_RNG_CHUNK_1);
+ bytes_out &= VIA_XSTORE_CNT_MASK;
+ if (bytes_out || !wait)
+ break;
+ udelay(10);
+ }
+ return bytes_out ? 1 : 0;
}

static int via_rng_data_read(struct hwrng *rng, u32 *data)
diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h
index 21ea761..85d1191 100644
--- a/include/linux/hw_random.h
+++ b/include/linux/hw_random.h
@@ -33,7 +33,7 @@ struct hwrng {
const char *name;
int (*init)(struct hwrng *rng);
void (*cleanup)(struct hwrng *rng);
- int (*data_present)(struct hwrng *rng);
+ int (*data_present)(struct hwrng *rng, int wait);
int (*data_read)(struct hwrng *rng, u32 *data);
unsigned long priv;