From: LABBE Corentin Subject: [PATCH 5/5] hwrng: amd: Rework of the amd768-hwrng driver Date: Fri, 19 Aug 2016 15:42:57 +0200 Message-ID: <1471614177-12380-5-git-send-email-clabbe.montjoie@gmail.com> References: <1471614177-12380-1-git-send-email-clabbe.montjoie@gmail.com> Cc: linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, LABBE Corentin To: herbert@gondor.apana.org.au, mpm@selenic.com Return-path: In-Reply-To: <1471614177-12380-1-git-send-email-clabbe.montjoie@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org This patch convert the hwrng interface used by amd768-rng to its new API by replacing data_read()/data_present() by read(). Furthermore, Instead of having two global variable, it's better to use a private struct. This will permit to remove amd_pdev variable. Finally, Instead of accessing hw directly via pmbase, it's better to access after ioport_map() via ioread32/iowrite32. Signed-off-by: LABBE Corentin --- drivers/char/hw_random/amd-rng.c | 151 +++++++++++++++++++++++++-------------- 1 file changed, 99 insertions(+), 52 deletions(-) diff --git a/drivers/char/hw_random/amd-rng.c b/drivers/char/hw_random/amd-rng.c index 9ddc99c..efdd853 100644 --- a/drivers/char/hw_random/amd-rng.c +++ b/drivers/char/hw_random/amd-rng.c @@ -32,6 +32,14 @@ #define DRV_NAME "AMD768-HWRNG" +#define GEN_CFG_REG1 0x40 +#define GEN_CFG_REG2 0x41 +#define SMIO_SPACEPTR 0x58 +#define RNGDATA 0x00 +#define RNGDONE 0x04 +#define PMBASE_OFFSET 0xF0 +#define PMBASE_SIZE 8 + /* * Data for PCI driver interface * @@ -39,6 +47,7 @@ * PCI ids via MODULE_DEVICE_TABLE. We do not actually * register a pci_driver, because someone else might one day * want to register another driver on the same PCI id. + * Like i2c-amd756 */ static const struct pci_device_id pci_tbl[] = { { PCI_VDEVICE(AMD, 0x7443), 0, }, @@ -47,112 +56,150 @@ 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; + u32 pmbase; +}; -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) { u8 rnen; + struct amd768_priv *priv = (struct amd768_priv *)rng->priv; - pci_read_config_byte(amd_pdev, 0x40, &rnen); + pci_read_config_byte(priv->pcidev, GEN_CFG_REG1, &rnen); rnen |= BIT(7); /* RNG on */ - pci_write_config_byte(amd_pdev, 0x40, rnen); + pci_write_config_byte(priv->pcidev, GEN_CFG_REG1, rnen); - pci_read_config_byte(amd_pdev, 0x41, &rnen); + pci_read_config_byte(priv->pcidev, GEN_CFG_REG2, &rnen); rnen |= BIT(7); /* PMIO enable */ - pci_write_config_byte(amd_pdev, 0x41, rnen); - + pci_write_config_byte(priv->pcidev, GEN_CFG_REG2, rnen); return 0; } static void amd_rng_cleanup(struct hwrng *rng) { u8 rnen; + struct amd768_priv *priv = (struct amd768_priv *)rng->priv; - pci_read_config_byte(amd_pdev, 0x40, &rnen); + pci_read_config_byte(priv->pcidev, GEN_CFG_REG1, &rnen); rnen &= ~BIT(7); /* RNG off */ - pci_write_config_byte(amd_pdev, 0x40, rnen); + pci_write_config_byte(priv->pcidev, GEN_CFG_REG1, rnen); } static struct hwrng amd_rng = { .name = DRV_NAME, + .read = amd_rng_read, .init = amd_rng_init, .cleanup = amd_rng_cleanup, - .data_present = amd_rng_data_present, - .data_read = amd_rng_data_read, }; -static int __init mod_init(void) +static int mod_init(void) { - int err = -ENODEV; + int err; 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); if (ent) goto found; } - /* Device not found. */ - goto out; - + return -ENODEV; found: - err = pci_read_config_dword(pdev, 0x58, &pmbase); + + err = pci_read_config_dword(pdev, SMIO_SPACEPTR, &pmbase); if (err) - goto out; - err = -EIO; + return err; + pmbase &= 0x0000FF00; - if (pmbase == 0) - goto out; - 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; + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + if (!request_region(pmbase + PMBASE_OFFSET, PMBASE_SIZE, DRV_NAME)) { + pr_err(DRV_NAME "region 0x%x already in use!\n", pmbase); + goto err_pmbase; + } + + priv->iobase = ioport_map(pmbase + PMBASE_OFFSET, PMBASE_SIZE); + if (!priv->iobase) { + pr_err(DRV_NAME "Cannot map ioport\n"); + err = -EINVAL; + goto err_iomap; } - 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); if (err) { - pr_err(DRV_NAME " registering failed (%d)\n", err); - release_region(pmbase + 0xF0, 8); - goto out; + pr_err(DRV_NAME "Cannot register HWRNG %d\n", err); + goto err_hwrng; } -out: + return 0; + +err_hwrng: + ioport_unmap(priv->iobase); +err_iomap: + release_region(pmbase + PMBASE_OFFSET, PMBASE_SIZE); +err_pmbase: + kfree(priv); return err; } -static void __exit mod_exit(void) +static void mod_exit(void) { - u32 pmbase = (unsigned long)amd_rng.priv; + struct amd768_priv *priv; + + priv = (struct amd768_priv *)amd_rng.priv; - release_region(pmbase + 0xF0, 8); hwrng_unregister(&amd_rng); + + ioport_unmap(priv->iobase); + + release_region(priv->pmbase + PMBASE_OFFSET, PMBASE_SIZE); + + kfree(priv); } module_init(mod_init); -- 2.7.3