1 files changed, 78 insertions, 62 deletions

diff --git a/drivers/char/hw_random/amd-rng.c b/drivers/char/hw_random/amd-rng.c
index 48f6a83cdd61..4a99ac756f08 100644
--- a/drivers/char/hw_random/amd-rng.c
+++ b/drivers/char/hw_random/amd-rng.c
@@ -24,16 +24,18 @@
  * warranty of any kind, whether express or implied.
  */
 
-#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/hw_random.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/pci.h>
-#include <linux/hw_random.h>
-#include <linux/delay.h>
-#include <asm/io.h>
 
+#define DRV_NAME "AMD768-HWRNG"
 
-#define PFX	KBUILD_MODNAME ": "
-
+#define RNGDATA		0x00
+#define RNGDONE		0x04
+#define PMBASE_OFFSET	0xF0
+#define PMBASE_SIZE	8
 
 /*
  * Data for PCI driver interface
@@ -50,72 +52,84 @@ static const struct pci_device_id pci_tbl[] = {
 };
 MODULE_DEVICE_TABLE(pci, pci_tbl);
 
-static struct pci_dev *amd_pdev;
-
+struct amd768_priv {
+	void __iomem *iobase;
+	struct pci_dev *pcidev;
+};
 
-static int amd_rng_data_present(struct hwrng *rng, int wait)
+static int amd_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
 {
-	u32 pmbase = (u32)rng->priv;
-	int data, i;
-
-	for (i = 0; i < 20; i++) {
-		data = !!(inl(pmbase + 0xF4) & 1);
-		if (data || !wait)
-			break;
-		udelay(10);
+	u32 *data = buf;
+	struct amd768_priv *priv = (struct amd768_priv *)rng->priv;
+	size_t read = 0;
+	/* We will wait at maximum one time per read */
+	int timeout = max / 4 + 1;
+
+	/*
+	 * RNG data is available when RNGDONE is set to 1
+	 * New random numbers are generated approximately 128 microseconds
+	 * after RNGDATA is read
+	 */
+	while (read < max) {
+		if (ioread32(priv->iobase + RNGDONE) == 0) {
+			if (wait) {
+				/* Delay given by datasheet */
+				usleep_range(128, 196);
+				if (timeout-- == 0)
+					return read;
+			} else {
+				return 0;
+			}
+		} else {
+			*data = ioread32(priv->iobase + RNGDATA);
+			data++;
+			read += 4;
+		}
 	}
-	return data;
-}
 
-static int amd_rng_data_read(struct hwrng *rng, u32 *data)
-{
-	u32 pmbase = (u32)rng->priv;
-
-	*data = inl(pmbase + 0xF0);
-
-	return 4;
+	return read;
 }
 
 static int amd_rng_init(struct hwrng *rng)
 {
+	struct amd768_priv *priv = (struct amd768_priv *)rng->priv;
 	u8 rnen;
 
-	pci_read_config_byte(amd_pdev, 0x40, &rnen);
-	rnen |= (1 << 7);	/* RNG on */
-	pci_write_config_byte(amd_pdev, 0x40, rnen);
+	pci_read_config_byte(priv->pcidev, 0x40, &rnen);
+	rnen |= BIT(7);	/* RNG on */
+	pci_write_config_byte(priv->pcidev, 0x40, rnen);
 
-	pci_read_config_byte(amd_pdev, 0x41, &rnen);
-	rnen |= (1 << 7);	/* PMIO enable */
-	pci_write_config_byte(amd_pdev, 0x41, rnen);
+	pci_read_config_byte(priv->pcidev, 0x41, &rnen);
+	rnen |= BIT(7);	/* PMIO enable */
+	pci_write_config_byte(priv->pcidev, 0x41, rnen);
 
 	return 0;
 }
 
 static void amd_rng_cleanup(struct hwrng *rng)
 {
+	struct amd768_priv *priv = (struct amd768_priv *)rng->priv;
 	u8 rnen;
 
-	pci_read_config_byte(amd_pdev, 0x40, &rnen);
-	rnen &= ~(1 << 7);	/* RNG off */
-	pci_write_config_byte(amd_pdev, 0x40, rnen);
+	pci_read_config_byte(priv->pcidev, 0x40, &rnen);
+	rnen &= ~BIT(7);	/* RNG off */
+	pci_write_config_byte(priv->pcidev, 0x40, rnen);
 }
 
-
 static struct hwrng amd_rng = {
 	.name		= "amd",
 	.init		= amd_rng_init,
 	.cleanup	= amd_rng_cleanup,
-	.data_present	= amd_rng_data_present,
-	.data_read	= amd_rng_data_read,
+	.read		= amd_rng_read,
 };
 
-
 static int __init mod_init(void)
 {
 	int err = -ENODEV;
 	struct pci_dev *pdev = NULL;
 	const struct pci_device_id *ent;
 	u32 pmbase;
+	struct amd768_priv *priv;
 
 	for_each_pci_dev(pdev) {
 		ent = pci_match_id(pci_tbl, pdev);
@@ -123,42 +137,44 @@ static int __init mod_init(void)
 			goto found;
 	}
 	/* Device not found. */
-	goto out;
+	return -ENODEV;
 
 found:
 	err = pci_read_config_dword(pdev, 0x58, &pmbase);
 	if (err)
-		goto out;
-	err = -EIO;
+		return err;
+
 	pmbase &= 0x0000FF00;
 	if (pmbase == 0)
-		goto out;
-	if (!request_region(pmbase + 0xF0, 8, "AMD HWRNG")) {
-		dev_err(&pdev->dev, "AMD HWRNG region 0x%x already in use!\n",
+		return -EIO;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	if (!devm_request_region(&pdev->dev, pmbase + PMBASE_OFFSET,
+				PMBASE_SIZE, DRV_NAME)) {
+		dev_err(&pdev->dev, DRV_NAME " region 0x%x already in use!\n",
 			pmbase + 0xF0);
-		err = -EBUSY;
-		goto out;
+		return -EBUSY;
 	}
-	amd_rng.priv = (unsigned long)pmbase;
-	amd_pdev = pdev;
-
-	pr_info("AMD768 RNG detected\n");
-	err = hwrng_register(&amd_rng);
-	if (err) {
-		pr_err(PFX "RNG registering failed (%d)\n",
-		       err);
-		release_region(pmbase + 0xF0, 8);
-		goto out;
+
+	priv->iobase = devm_ioport_map(&pdev->dev, pmbase + PMBASE_OFFSET,
+			PMBASE_SIZE);
+	if (!priv->iobase) {
+		pr_err(DRV_NAME "Cannot map ioport\n");
+		return -ENOMEM;
 	}
-out:
-	return err;
+
+	amd_rng.priv = (unsigned long)priv;
+	priv->pcidev = pdev;
+
+	pr_info(DRV_NAME " detected\n");
+	return devm_hwrng_register(&pdev->dev, &amd_rng);
 }
 
 static void __exit mod_exit(void)
 {
-	u32 pmbase = (unsigned long)amd_rng.priv;
-	release_region(pmbase + 0xF0, 8);
-	hwrng_unregister(&amd_rng);
 }
 
 module_init(mod_init);