[HIFN]: Add support for using the random number generator
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
---
commit ad6c98ed1e38edf4da775780b59a0faf56ff42a7
tree 7c733d13a387e18bace04fe904bed9937c0bb628
parent 3ca22e0c464bc84bffdf63d65c1094b2fed78bff
author Patrick McHardy <kaber@xxxxxxxxx> Sat, 17 Nov 2007 20:15:40 +0100
committer Patrick McHardy <kaber@xxxxxxxxx> Sat, 17 Nov 2007 20:15:40 +0100
drivers/crypto/hifn_795x.c | 65 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 65 insertions(+), 0 deletions(-)
diff --git a/drivers/crypto/hifn_795x.c b/drivers/crypto/hifn_795x.c
index 81306b7..fe5289a 100644
--- a/drivers/crypto/hifn_795x.c
+++ b/drivers/crypto/hifn_795x.c
@@ -31,6 +31,7 @@
#include <linux/highmem.h>
#include <linux/interrupt.h>
#include <linux/crypto.h>
+#include <linux/hw_random.h>
#include <crypto/algapi.h>
#include <crypto/des.h>
@@ -458,6 +459,14 @@ struct hifn_device
struct crypto_queue queue;
struct list_head alg_list;
+
+ unsigned int pk_clk_freq;
+
+#if defined(CONFIG_HW_RANDOM) || defined(CONFIG_HW_RANDOM_MODULE)
+ cycles_t rng_wait_cycles;
+ cycles_t rngtime;
+ struct hwrng rng;
+#endif
};
#define HIFN_D_LENGTH 0x0000ffff
@@ -785,6 +794,49 @@ static struct pci2id {
}
};
+#if defined(CONFIG_HW_RANDOM) || defined(CONFIG_HW_RANDOM_MODULE)
+static int hifn_rng_data_present(struct hwrng *rng)
+{
+ struct hifn_device *dev = (struct hifn_device *)rng->priv;
+
+ return get_cycles() - dev->rngtime > dev->rng_wait_cycles;
+}
+
+static int hifn_rng_data_read(struct hwrng *rng, u32 *data)
+{
+ struct hifn_device *dev = (struct hifn_device *)rng->priv;
+
+ *data = hifn_read_1(dev, HIFN_1_RNG_DATA);
+ dev->rngtime = get_cycles();
+ return 4;
+}
+
+static int hifn_register_rng(struct hifn_device *dev)
+{
+ /*
+ * We must wait at least 256 Pk_clk cycles between two reads of
+ * the rng. Calculate corresponding amount CPU cycles based on
+ * a CPU speed of 4GHz.
+ */
+ dev->rng_wait_cycles = 256 * DIV_ROUND_UP(4000U, dev->pk_clk_freq);
+
+ dev->rng.name = dev->name;
+ dev->rng.data_present = hifn_rng_data_present,
+ dev->rng.data_read = hifn_rng_data_read,
+ dev->rng.priv = (unsigned long)dev;
+
+ return hwrng_register(&dev->rng);
+}
+
+static void hifn_unregister_rng(struct hifn_device *dev)
+{
+ hwrng_unregister(&dev->rng);
+}
+#else
+#define hifn_register_rng(dev) 0
+#define hifn_unregister_rng(dev)
+#endif
+
static int hifn_init_pubrng(struct hifn_device *dev)
{
int i;
@@ -936,6 +988,14 @@ static void hifn_init_pll(struct hifn_device *dev)
pllcfg |= HIFN_PLL_IS_9_12;
hifn_write_1(dev, HIFN_1_PLL, pllcfg);
+
+ /*
+ * The Fpk_clk runs at half the total speed. Its frequency is needed to
+ * calculate the minimum time between two reads of the rng. Since 33MHz
+ * is actually 33.333... we overestimate the frequency here, resulting
+ * in slightly larger intervals.
+ */
+ dev->pk_clk_freq = (freq + 1) * m / 2;
}
static void hifn_init_registers(struct hifn_device *dev)
@@ -2597,6 +2657,10 @@ static int hifn_probe(struct pci_dev *pdev, const struct pci_device_id *id)
if (err)
goto err_out_stop_device;
+ err = hifn_register_rng(dev);
+ if (err)
+ goto err_out_stop_device;
+
INIT_DELAYED_WORK(&dev->work, hifn_work);
schedule_delayed_work(&dev->work, HZ);
@@ -2647,6 +2711,7 @@ static void hifn_remove(struct pci_dev *pdev)
flush_scheduled_work();
hifn_unregister_alg(dev);
+ hifn_unregister_rng(dev);
hifn_reset_dma(dev, 1);
hifn_stop_device(dev);
-
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