linux-kernel - [PATCH v3 6/8] hwrng: amd: Replace global variable with private struct

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Date:   Fri, 26 Aug 2016 13:11:34 +0200
From:   LABBE Corentin <clabbe.montjoie@...il.com>
To:     mpm@...enic.com, herbert@...dor.apana.org.au,
        linux-crypto@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        LABBE Corentin <clabbe.montjoie@...il.com>
Subject: [PATCH v3 6/8] hwrng: amd: Replace global variable with private struct

Instead of having two global variable, it's better to use a
private struct. This will permit to remove amd_pdev variable

Signed-off-by: LABBE Corentin <clabbe.montjoie@...il.com>
---
 drivers/char/hw_random/amd-rng.c | 57 ++++++++++++++++++++++++++--------------
 1 file changed, 38 insertions(+), 19 deletions(-)

diff --git a/drivers/char/hw_random/amd-rng.c b/drivers/char/hw_random/amd-rng.c
index 383e197..4ef94e9 100644
--- a/drivers/char/hw_random/amd-rng.c
+++ b/drivers/char/hw_random/amd-rng.c
@@ -47,15 +47,18 @@ static const struct pci_device_id pci_tbl[] = {
 };
 MODULE_DEVICE_TABLE(pci, pci_tbl);
 
-static struct pci_dev *amd_pdev;
+struct amd768_priv {
+	struct pci_dev *pcidev;
+	u32 pmbase;
+};
 
 static int amd_rng_data_present(struct hwrng *rng, int wait)
 {
-	u32 pmbase = (u32)rng->priv;
+	struct amd768_priv *priv = (struct amd768_priv *)rng->priv;
 	int data, i;
 
 	for (i = 0; i < 20; i++) {
-		data = !!(inl(pmbase + 0xF4) & 1);
+		data = !!(inl(priv->pmbase + 0xF4) & 1);
 		if (data || !wait)
 			break;
 		udelay(10);
@@ -65,35 +68,37 @@ static int amd_rng_data_present(struct hwrng *rng, int wait)
 
 static int amd_rng_data_read(struct hwrng *rng, u32 *data)
 {
-	u32 pmbase = (u32)rng->priv;
+	struct amd768_priv *priv = (struct amd768_priv *)rng->priv;
 
-	*data = inl(pmbase + 0xF0);
+	*data = inl(priv->pmbase + 0xF0);
 
 	return 4;
 }
 
 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);
+	pci_read_config_byte(priv->pcidev, 0x40, &rnen);
 	rnen |= BIT(7);	/* RNG on */
-	pci_write_config_byte(amd_pdev, 0x40, rnen);
+	pci_write_config_byte(priv->pcidev, 0x40, rnen);
 
-	pci_read_config_byte(amd_pdev, 0x41, &rnen);
+	pci_read_config_byte(priv->pcidev, 0x41, &rnen);
 	rnen |= BIT(7);	/* PMIO enable */
-	pci_write_config_byte(amd_pdev, 0x41, rnen);
+	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);
+	pci_read_config_byte(priv->pcidev, 0x40, &rnen);
 	rnen &= ~BIT(7);	/* RNG off */
-	pci_write_config_byte(amd_pdev, 0x40, rnen);
+	pci_write_config_byte(priv->pcidev, 0x40, rnen);
 }
 
 static struct hwrng amd_rng = {
@@ -110,6 +115,7 @@ static int __init mod_init(void)
 	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);
@@ -117,24 +123,30 @@ 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;
+		return -EIO;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
 	if (!request_region(pmbase + 0xF0, 8, DRV_NAME)) {
 		dev_err(&pdev->dev, DRV_NAME " region 0x%x already in use!\n",
 			pmbase + 0xF0);
 		err = -EBUSY;
 		goto out;
 	}
-	amd_rng.priv = (unsigned long)pmbase;
-	amd_pdev = pdev;
+	amd_rng.priv = (unsigned long)priv;
+	priv->pmbase = pmbase;
+	priv->pcidev = pdev;
 
 	pr_info(DRV_NAME " detected\n");
 	err = hwrng_register(&amd_rng);
@@ -143,17 +155,24 @@ found:
 		release_region(pmbase + 0xF0, 8);
 		goto out;
 	}
+	return 0;
+
 out:
+	kfree(priv);
 	return err;
 }
 
 static void __exit mod_exit(void)
 {
-	u32 pmbase = (unsigned long)amd_rng.priv;
+	struct amd768_priv *priv;
+
+	priv = (struct amd768_priv *)amd_rng.priv;
 
 	hwrng_unregister(&amd_rng);
 
-	release_region(pmbase + 0xF0, 8);
+	release_region(priv->pmbase + 0xF0, 8);
+
+	kfree(priv);
 }
 
 module_init(mod_init);
-- 
2.7.3