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Subject[HIFN 03/03]: Add support for using the random number generator
Date
[HIFN]: Add support for using the random number generator

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

---
commit 352a65d036f53c1e124bef4205d6fcedb78eac2c
tree 190bb0b4a1795e55096552f743af996df2766070
parent 70467fae3a656562f86adefdfe6d54e3ca20feeb
author Patrick McHardy <kaber@trash.net> Sun, 18 Nov 2007 22:09:17 +0100
committer Patrick McHardy <kaber@trash.net> Sun, 18 Nov 2007 22:09:17 +0100
drivers/crypto/hifn_795x.c | 82 +++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 81 insertions(+), 1 deletions(-)
diff --git a/drivers/crypto/hifn_795x.c b/drivers/crypto/hifn_795x.c
index de594bc..1a19700 100644
--- a/drivers/crypto/hifn_795x.c
+++ b/drivers/crypto/hifn_795x.c
@@ -31,6 +31,8 @@
#include <linux/highmem.h>
#include <linux/interrupt.h>
#include <linux/crypto.h>
+#include <linux/hw_random.h>
+#include <linux/ktime.h>

#include <crypto/algapi.h>
#include <crypto/des.h>
@@ -458,6 +460,14 @@ 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)
+ unsigned int rng_wait_time;
+ ktime_t rngtime;
+ struct hwrng rng;
+#endif
};

#define HIFN_D_LENGTH 0x0000ffff
@@ -785,6 +795,56 @@ static struct pci2id {
}
};

+#if defined(CONFIG_HW_RANDOM) || defined(CONFIG_HW_RANDOM_MODULE)
+static int hifn_rng_data_present(struct hwrng *rng, int wait)
+{
+ struct hifn_device *dev = (struct hifn_device *)rng->priv;
+ s64 nsec;
+
+ nsec = ktime_to_ns(ktime_sub(ktime_get(), dev->rngtime));
+ nsec -= dev->rng_wait_time;
+ if (nsec <= 0)
+ return 1;
+ if (!wait)
+ return 0;
+ ndelay(nsec);
+ return 1;
+}
+
+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 = ktime_get();
+ 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.
+ */
+ dev->rng_wait_time = DIV_ROUND_UP(NSEC_PER_SEC, dev->pk_clk_freq) *
+ 256;
+
+ 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;
@@ -820,6 +880,11 @@ static int hifn_init_pubrng(struct hifn_device *dev)
dprintk("Chip %s: RNG engine has been successfully initialised.\n",
dev->name);

+#if defined(CONFIG_HW_RANDOM) || defined(CONFIG_HW_RANDOM_MODULE)
+ /* First value must be discarded */
+ hifn_read_1(dev, HIFN_1_RNG_DATA);
+ dev->rngtime = ktime_get();
+#endif
return 0;
}

@@ -952,6 +1017,14 @@ static void hifn_init_pll(struct hifn_device *dev)
/* Switch the engines to the PLL */
hifn_write_1(dev, HIFN_1_PLL, pllcfg |
HIFN_PLL_PK_CLK_PLL | HIFN_PLL_PE_CLK_PLL);
+
+ /*
+ * 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 = 1000000 * (freq + 1) * m / 2;
}

static void hifn_init_registers(struct hifn_device *dev)
@@ -2609,10 +2682,14 @@ static int hifn_probe(struct pci_dev *pdev, const struct pci_device_id *id)
if (err)
goto err_out_stop_device;

- err = hifn_register_alg(dev);
+ err = hifn_register_rng(dev);
if (err)
goto err_out_stop_device;

+ err = hifn_register_alg(dev);
+ if (err)
+ goto err_out_unregister_rng;
+
INIT_DELAYED_WORK(&dev->work, hifn_work);
schedule_delayed_work(&dev->work, HZ);

@@ -2622,6 +2699,8 @@ static int hifn_probe(struct pci_dev *pdev, const struct pci_device_id *id)

return 0;

+err_out_unregister_rng:
+ hifn_unregister_rng(dev);
err_out_stop_device:
hifn_reset_dma(dev, 1);
hifn_stop_device(dev);
@@ -2662,6 +2741,7 @@ static void hifn_remove(struct pci_dev *pdev)
cancel_delayed_work(&dev->work);
flush_scheduled_work();

+ hifn_unregister_rng(dev);
hifn_unregister_alg(dev);
hifn_reset_dma(dev, 1);
hifn_stop_device(dev);
-
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