[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>
Acked-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/hw_random/amd-rng.c b/drivers/char/hw_random/amd-rng.c
index 556fd81..c422e87 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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;