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linux_dsm_epyc7002/drivers/char/hw_random/omap-rng.c
Nishanth Menon 61dc0a446e hwrng: omap - Fix assumption that runtime_get_sync will always succeed 
pm_runtime_get_sync does return a error value that must be checked for
error conditions, else, due to various reasons, the device maynot be
enabled and the system will crash due to lack of clock to the hardware
module.

Before:
12.562784] [00000000] *pgd=fe193835
12.562792] Internal error: : 1406 [#1] SMP ARM
[...]
12.562864] CPU: 1 PID: 241 Comm: modprobe Not tainted 4.7.0-rc4-next-20160624 #2
12.562867] Hardware name: Generic DRA74X (Flattened Device Tree)
12.562872] task: ed51f140 ti: ed44c000 task.ti: ed44c000
12.562886] PC is at omap4_rng_init+0x20/0x84 [omap_rng]
12.562899] LR is at set_current_rng+0xc0/0x154 [rng_core]
[...]

After the proper checks:
[   94.366705] omap_rng 48090000.rng: _od_fail_runtime_resume: FIXME:
missing hwmod/omap_dev info
[   94.375767] omap_rng 48090000.rng: Failed to runtime_get device -19
[   94.382351] omap_rng 48090000.rng: initialization failed.

Fixes: 665d92fa85 ("hwrng: OMAP: convert to use runtime PM")
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-06-27 16:57:49 +08:00

473 lines
12 KiB
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/*
* omap-rng.c - RNG driver for TI OMAP CPU family
*
* Author: Deepak Saxena <dsaxena@plexity.net>
*
* Copyright 2005 (c) MontaVista Software, Inc.
*
* Mostly based on original driver:
*
* Copyright (C) 2005 Nokia Corporation
* Author: Juha Yrjölä <juha.yrjola@nokia.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/hw_random.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#define RNG_REG_STATUS_RDY (1 << 0)
#define RNG_REG_INTACK_RDY_MASK (1 << 0)
#define RNG_REG_INTACK_SHUTDOWN_OFLO_MASK (1 << 1)
#define RNG_SHUTDOWN_OFLO_MASK (1 << 1)
#define RNG_CONTROL_STARTUP_CYCLES_SHIFT 16
#define RNG_CONTROL_STARTUP_CYCLES_MASK (0xffff << 16)
#define RNG_CONTROL_ENABLE_TRNG_SHIFT 10
#define RNG_CONTROL_ENABLE_TRNG_MASK (1 << 10)
#define RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT 16
#define RNG_CONFIG_MAX_REFIL_CYCLES_MASK (0xffff << 16)
#define RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT 0
#define RNG_CONFIG_MIN_REFIL_CYCLES_MASK (0xff << 0)
#define RNG_CONTROL_STARTUP_CYCLES 0xff
#define RNG_CONFIG_MIN_REFIL_CYCLES 0x21
#define RNG_CONFIG_MAX_REFIL_CYCLES 0x22
#define RNG_ALARMCNT_ALARM_TH_SHIFT 0x0
#define RNG_ALARMCNT_ALARM_TH_MASK (0xff << 0)
#define RNG_ALARMCNT_SHUTDOWN_TH_SHIFT 16
#define RNG_ALARMCNT_SHUTDOWN_TH_MASK (0x1f << 16)
#define RNG_ALARM_THRESHOLD 0xff
#define RNG_SHUTDOWN_THRESHOLD 0x4
#define RNG_REG_FROENABLE_MASK 0xffffff
#define RNG_REG_FRODETUNE_MASK 0xffffff
#define OMAP2_RNG_OUTPUT_SIZE 0x4
#define OMAP4_RNG_OUTPUT_SIZE 0x8
enum {
RNG_OUTPUT_L_REG = 0,
RNG_OUTPUT_H_REG,
RNG_STATUS_REG,
RNG_INTMASK_REG,
RNG_INTACK_REG,
RNG_CONTROL_REG,
RNG_CONFIG_REG,
RNG_ALARMCNT_REG,
RNG_FROENABLE_REG,
RNG_FRODETUNE_REG,
RNG_ALARMMASK_REG,
RNG_ALARMSTOP_REG,
RNG_REV_REG,
RNG_SYSCONFIG_REG,
};
static const u16 reg_map_omap2[] = {
[RNG_OUTPUT_L_REG] = 0x0,
[RNG_STATUS_REG] = 0x4,
[RNG_CONFIG_REG] = 0x28,
[RNG_REV_REG] = 0x3c,
[RNG_SYSCONFIG_REG] = 0x40,
};
static const u16 reg_map_omap4[] = {
[RNG_OUTPUT_L_REG] = 0x0,
[RNG_OUTPUT_H_REG] = 0x4,
[RNG_STATUS_REG] = 0x8,
[RNG_INTMASK_REG] = 0xc,
[RNG_INTACK_REG] = 0x10,
[RNG_CONTROL_REG] = 0x14,
[RNG_CONFIG_REG] = 0x18,
[RNG_ALARMCNT_REG] = 0x1c,
[RNG_FROENABLE_REG] = 0x20,
[RNG_FRODETUNE_REG] = 0x24,
[RNG_ALARMMASK_REG] = 0x28,
[RNG_ALARMSTOP_REG] = 0x2c,
[RNG_REV_REG] = 0x1FE0,
[RNG_SYSCONFIG_REG] = 0x1FE4,
};
struct omap_rng_dev;
/**
* struct omap_rng_pdata - RNG IP block-specific data
* @regs: Pointer to the register offsets structure.
* @data_size: No. of bytes in RNG output.
* @data_present: Callback to determine if data is available.
* @init: Callback for IP specific initialization sequence.
* @cleanup: Callback for IP specific cleanup sequence.
*/
struct omap_rng_pdata {
u16 *regs;
u32 data_size;
u32 (*data_present)(struct omap_rng_dev *priv);
int (*init)(struct omap_rng_dev *priv);
void (*cleanup)(struct omap_rng_dev *priv);
};
struct omap_rng_dev {
void __iomem *base;
struct device *dev;
const struct omap_rng_pdata *pdata;
};
static inline u32 omap_rng_read(struct omap_rng_dev *priv, u16 reg)
{
return __raw_readl(priv->base + priv->pdata->regs[reg]);
}
static inline void omap_rng_write(struct omap_rng_dev *priv, u16 reg,
u32 val)
{
__raw_writel(val, priv->base + priv->pdata->regs[reg]);
}
static int omap_rng_data_present(struct hwrng *rng, int wait)
{
struct omap_rng_dev *priv;
int data, i;
priv = (struct omap_rng_dev *)rng->priv;
for (i = 0; i < 20; i++) {
data = priv->pdata->data_present(priv);
if (data || !wait)
break;
/* RNG produces data fast enough (2+ MBit/sec, even
* during "rngtest" loads, that these delays don't
* seem to trigger. We *could* use the RNG IRQ, but
* that'd be higher overhead ... so why bother?
*/
udelay(10);
}
return data;
}
static int omap_rng_data_read(struct hwrng *rng, u32 *data)
{
struct omap_rng_dev *priv;
u32 data_size, i;
priv = (struct omap_rng_dev *)rng->priv;
data_size = priv->pdata->data_size;
for (i = 0; i < data_size / sizeof(u32); i++)
data[i] = omap_rng_read(priv, RNG_OUTPUT_L_REG + i);
if (priv->pdata->regs[RNG_INTACK_REG])
omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_RDY_MASK);
return data_size;
}
static int omap_rng_init(struct hwrng *rng)
{
struct omap_rng_dev *priv;
priv = (struct omap_rng_dev *)rng->priv;
return priv->pdata->init(priv);
}
static void omap_rng_cleanup(struct hwrng *rng)
{
struct omap_rng_dev *priv;
priv = (struct omap_rng_dev *)rng->priv;
priv->pdata->cleanup(priv);
}
static struct hwrng omap_rng_ops = {
.name = "omap",
.data_present = omap_rng_data_present,
.data_read = omap_rng_data_read,
.init = omap_rng_init,
.cleanup = omap_rng_cleanup,
};
static inline u32 omap2_rng_data_present(struct omap_rng_dev *priv)
{
return omap_rng_read(priv, RNG_STATUS_REG) ? 0 : 1;
}
static int omap2_rng_init(struct omap_rng_dev *priv)
{
omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x1);
return 0;
}
static void omap2_rng_cleanup(struct omap_rng_dev *priv)
{
omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x0);
}
static struct omap_rng_pdata omap2_rng_pdata = {
.regs = (u16 *)reg_map_omap2,
.data_size = OMAP2_RNG_OUTPUT_SIZE,
.data_present = omap2_rng_data_present,
.init = omap2_rng_init,
.cleanup = omap2_rng_cleanup,
};
#if defined(CONFIG_OF)
static inline u32 omap4_rng_data_present(struct omap_rng_dev *priv)
{
return omap_rng_read(priv, RNG_STATUS_REG) & RNG_REG_STATUS_RDY;
}
static int omap4_rng_init(struct omap_rng_dev *priv)
{
u32 val;
/* Return if RNG is already running. */
if (omap_rng_read(priv, RNG_CONTROL_REG) & RNG_CONTROL_ENABLE_TRNG_MASK)
return 0;
val = RNG_CONFIG_MIN_REFIL_CYCLES << RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT;
val |= RNG_CONFIG_MAX_REFIL_CYCLES << RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT;
omap_rng_write(priv, RNG_CONFIG_REG, val);
omap_rng_write(priv, RNG_FRODETUNE_REG, 0x0);
omap_rng_write(priv, RNG_FROENABLE_REG, RNG_REG_FROENABLE_MASK);
val = RNG_ALARM_THRESHOLD << RNG_ALARMCNT_ALARM_TH_SHIFT;
val |= RNG_SHUTDOWN_THRESHOLD << RNG_ALARMCNT_SHUTDOWN_TH_SHIFT;
omap_rng_write(priv, RNG_ALARMCNT_REG, val);
val = RNG_CONTROL_STARTUP_CYCLES << RNG_CONTROL_STARTUP_CYCLES_SHIFT;
val |= RNG_CONTROL_ENABLE_TRNG_MASK;
omap_rng_write(priv, RNG_CONTROL_REG, val);
return 0;
}
static void omap4_rng_cleanup(struct omap_rng_dev *priv)
{
int val;
val = omap_rng_read(priv, RNG_CONTROL_REG);
val &= ~RNG_CONTROL_ENABLE_TRNG_MASK;
omap_rng_write(priv, RNG_CONTROL_REG, val);
}
static irqreturn_t omap4_rng_irq(int irq, void *dev_id)
{
struct omap_rng_dev *priv = dev_id;
u32 fro_detune, fro_enable;
/*
* Interrupt raised by a fro shutdown threshold, do the following:
* 1. Clear the alarm events.
* 2. De tune the FROs which are shutdown.
* 3. Re enable the shutdown FROs.
*/
omap_rng_write(priv, RNG_ALARMMASK_REG, 0x0);
omap_rng_write(priv, RNG_ALARMSTOP_REG, 0x0);
fro_enable = omap_rng_read(priv, RNG_FROENABLE_REG);
fro_detune = ~fro_enable & RNG_REG_FRODETUNE_MASK;
fro_detune = fro_detune | omap_rng_read(priv, RNG_FRODETUNE_REG);
fro_enable = RNG_REG_FROENABLE_MASK;
omap_rng_write(priv, RNG_FRODETUNE_REG, fro_detune);
omap_rng_write(priv, RNG_FROENABLE_REG, fro_enable);
omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_SHUTDOWN_OFLO_MASK);
return IRQ_HANDLED;
}
static struct omap_rng_pdata omap4_rng_pdata = {
.regs = (u16 *)reg_map_omap4,
.data_size = OMAP4_RNG_OUTPUT_SIZE,
.data_present = omap4_rng_data_present,
.init = omap4_rng_init,
.cleanup = omap4_rng_cleanup,
};
static const struct of_device_id omap_rng_of_match[] = {
{
.compatible = "ti,omap2-rng",
.data = &omap2_rng_pdata,
},
{
.compatible = "ti,omap4-rng",
.data = &omap4_rng_pdata,
},
{},
};
MODULE_DEVICE_TABLE(of, omap_rng_of_match);
static int of_get_omap_rng_device_details(struct omap_rng_dev *priv,
struct platform_device *pdev)
{
const struct of_device_id *match;
struct device *dev = &pdev->dev;
int irq, err;
match = of_match_device(of_match_ptr(omap_rng_of_match), dev);
if (!match) {
dev_err(dev, "no compatible OF match\n");
return -EINVAL;
}
priv->pdata = match->data;
if (of_device_is_compatible(dev->of_node, "ti,omap4-rng")) {
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(dev, "%s: error getting IRQ resource - %d\n",
__func__, irq);
return irq;
}
err = devm_request_irq(dev, irq, omap4_rng_irq,
IRQF_TRIGGER_NONE, dev_name(dev), priv);
if (err) {
dev_err(dev, "unable to request irq %d, err = %d\n",
irq, err);
return err;
}
omap_rng_write(priv, RNG_INTMASK_REG, RNG_SHUTDOWN_OFLO_MASK);
}
return 0;
}
#else
static int of_get_omap_rng_device_details(struct omap_rng_dev *omap_rng,
struct platform_device *pdev)
{
return -EINVAL;
}
#endif
static int get_omap_rng_device_details(struct omap_rng_dev *omap_rng)
{
/* Only OMAP2/3 can be non-DT */
omap_rng->pdata = &omap2_rng_pdata;
return 0;
}
static int omap_rng_probe(struct platform_device *pdev)
{
struct omap_rng_dev *priv;
struct resource *res;
struct device *dev = &pdev->dev;
int ret;
priv = devm_kzalloc(dev, sizeof(struct omap_rng_dev), GFP_KERNEL);
if (!priv)
return -ENOMEM;
omap_rng_ops.priv = (unsigned long)priv;
platform_set_drvdata(pdev, priv);
priv->dev = dev;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->base = devm_ioremap_resource(dev, res);
if (IS_ERR(priv->base)) {
ret = PTR_ERR(priv->base);
goto err_ioremap;
}
pm_runtime_enable(&pdev->dev);
ret = pm_runtime_get_sync(&pdev->dev);
if (ret) {
dev_err(&pdev->dev, "Failed to runtime_get device: %d\n", ret);
pm_runtime_put_noidle(&pdev->dev);
goto err_ioremap;
}
ret = (dev->of_node) ? of_get_omap_rng_device_details(priv, pdev) :
get_omap_rng_device_details(priv);
if (ret)
goto err_ioremap;
ret = hwrng_register(&omap_rng_ops);
if (ret)
goto err_register;
dev_info(&pdev->dev, "OMAP Random Number Generator ver. %02x\n",
omap_rng_read(priv, RNG_REV_REG));
return 0;
err_register:
priv->base = NULL;
pm_runtime_disable(&pdev->dev);
err_ioremap:
dev_err(dev, "initialization failed.\n");
return ret;
}
static int omap_rng_remove(struct platform_device *pdev)
{
struct omap_rng_dev *priv = platform_get_drvdata(pdev);
hwrng_unregister(&omap_rng_ops);
priv->pdata->cleanup(priv);
pm_runtime_put_sync(&pdev->dev);
pm_runtime_disable(&pdev->dev);
return 0;
}
static int __maybe_unused omap_rng_suspend(struct device *dev)
{
struct omap_rng_dev *priv = dev_get_drvdata(dev);
priv->pdata->cleanup(priv);
pm_runtime_put_sync(dev);
return 0;
}
static int __maybe_unused omap_rng_resume(struct device *dev)
{
struct omap_rng_dev *priv = dev_get_drvdata(dev);
int ret;
ret = pm_runtime_get_sync(dev);
if (ret) {
dev_err(dev, "Failed to runtime_get device: %d\n", ret);
pm_runtime_put_noidle(dev);
return ret;
}
priv->pdata->init(priv);
return 0;
}
static SIMPLE_DEV_PM_OPS(omap_rng_pm, omap_rng_suspend, omap_rng_resume);
static struct platform_driver omap_rng_driver = {
.driver = {
.name = "omap_rng",
.pm = &omap_rng_pm,
.of_match_table = of_match_ptr(omap_rng_of_match),
},
.probe = omap_rng_probe,
.remove = omap_rng_remove,
};
module_platform_driver(omap_rng_driver);
MODULE_ALIAS("platform:omap_rng");
MODULE_AUTHOR("Deepak Saxena (and others)");
MODULE_LICENSE("GPL");
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