blob: e798bdbd482efe6d7e23937255c70fc38535fbaa [file] [log] [blame]
/*
* SNVS Security Violation Handler
* Copyright (C) 2012-2015 Freescale Semiconductor, Inc., All Rights Reserved
*/
#include "compat.h"
#include "intern.h"
#include "secvio.h"
#include "regs.h"
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
/*
* These names are associated with each violation handler.
* The source names were taken from MX6, and are based on recommendations
* for most common SoCs.
*/
static const u8 *violation_src_name[] = {
"CAAM Internal Security Violation",
"JTAG Alarm",
"Watchdog",
"(reserved)",
"External Boot",
"External Tamper Detect",
};
/* These names help describe security monitor state for the console */
static const u8 *snvs_ssm_state_name[] = {
"init",
"hard fail",
"(undef:2)",
"soft fail",
"(undef:4)",
"(undef:5)",
"(undef:6)",
"(undef:7)",
"transition",
"check",
"(undef:10)",
"non-secure",
"(undef:12)",
"trusted",
"(undef:14)",
"secure",
};
/* Top-level security violation interrupt */
static irqreturn_t snvs_secvio_interrupt(int irq, void *snvsdev)
{
struct device *dev = snvsdev;
struct snvs_secvio_drv_private *svpriv = dev_get_drvdata(dev);
clk_enable(svpriv->clk);
/* Check the HP secvio status register */
svpriv->irqcause = rd_reg32(&svpriv->svregs->hp.secvio_status) &
HP_SECVIOST_SECVIOMASK;
if (!svpriv->irqcause) {
clk_disable(svpriv->clk);
return IRQ_NONE;
}
/* Now ACK cause */
setbits32(&svpriv->svregs->hp.secvio_status, svpriv->irqcause);
/* And run deferred service */
preempt_disable();
tasklet_schedule(&svpriv->irqtask[smp_processor_id()]);
preempt_enable();
clk_disable(svpriv->clk);
return IRQ_HANDLED;
}
/* Deferred service handler. Tasklet arg is simply the SNVS dev */
static void snvs_secvio_dispatch(unsigned long indev)
{
struct device *dev = (struct device *)indev;
struct snvs_secvio_drv_private *svpriv = dev_get_drvdata(dev);
unsigned long flags;
int i;
/* Look through stored causes, call each handler if exists */
for (i = 0; i < MAX_SECVIO_SOURCES; i++)
if (svpriv->irqcause & (1 << i)) {
spin_lock_irqsave(&svpriv->svlock, flags);
svpriv->intsrc[i].handler(dev, i,
svpriv->intsrc[i].ext);
spin_unlock_irqrestore(&svpriv->svlock, flags);
};
/* Re-enable now-serviced interrupts */
setbits32(&svpriv->svregs->hp.secvio_intcfg, svpriv->irqcause);
}
/*
* Default cause handler, used in lieu of an application-defined handler.
* All it does at this time is print a console message. It could force a halt.
*/
static void snvs_secvio_default(struct device *dev, u32 cause, void *ext)
{
struct snvs_secvio_drv_private *svpriv = dev_get_drvdata(dev);
dev_err(dev, "Unhandled Security Violation Interrupt %d = %s\n",
cause, svpriv->intsrc[cause].intname);
}
/*
* Install an application-defined handler for a specified cause
* Arguments:
* - dev points to SNVS-owning device
* - cause interrupt source cause
* - handler application-defined handler, gets called with dev
* source cause, and locally-defined handler argument
* - cause_description points to a string to override the default cause
* name, this can be used as an alternate for error
* messages and such. If left NULL, the default
* description string is used.
* - ext pointer to any extra data needed by the handler.
*/
int snvs_secvio_install_handler(struct device *dev, enum secvio_cause cause,
void (*handler)(struct device *dev, u32 cause,
void *ext),
u8 *cause_description, void *ext)
{
unsigned long flags;
struct snvs_secvio_drv_private *svpriv;
svpriv = dev_get_drvdata(dev);
if ((handler == NULL) || (cause > SECVIO_CAUSE_SOURCE_5))
return -EINVAL;
spin_lock_irqsave(&svpriv->svlock, flags);
svpriv->intsrc[cause].handler = handler;
if (cause_description != NULL)
svpriv->intsrc[cause].intname = cause_description;
if (ext != NULL)
svpriv->intsrc[cause].ext = ext;
spin_unlock_irqrestore(&svpriv->svlock, flags);
return 0;
}
EXPORT_SYMBOL(snvs_secvio_install_handler);
/*
* Remove an application-defined handler for a specified cause (and, by
* implication, restore the "default".
* Arguments:
* - dev points to SNVS-owning device
* - cause interrupt source cause
*/
int snvs_secvio_remove_handler(struct device *dev, enum secvio_cause cause)
{
unsigned long flags;
struct snvs_secvio_drv_private *svpriv;
svpriv = dev_get_drvdata(dev);
if (cause > SECVIO_CAUSE_SOURCE_5)
return -EINVAL;
spin_lock_irqsave(&svpriv->svlock, flags);
svpriv->intsrc[cause].intname = violation_src_name[cause];
svpriv->intsrc[cause].handler = snvs_secvio_default;
svpriv->intsrc[cause].ext = NULL;
spin_unlock_irqrestore(&svpriv->svlock, flags);
return 0;
}
EXPORT_SYMBOL(snvs_secvio_remove_handler);
static int snvs_secvio_remove(struct platform_device *pdev)
{
struct device *svdev;
struct snvs_secvio_drv_private *svpriv;
int i;
svdev = &pdev->dev;
svpriv = dev_get_drvdata(svdev);
clk_enable(svpriv->clk);
/* Set all sources to nonfatal */
wr_reg32(&svpriv->svregs->hp.secvio_intcfg, 0);
/* Remove tasklets and release interrupt */
for_each_possible_cpu(i)
tasklet_kill(&svpriv->irqtask[i]);
clk_disable_unprepare(svpriv->clk);
free_irq(svpriv->irq, svdev);
iounmap(svpriv->svregs);
kfree(svpriv);
return 0;
}
static int snvs_secvio_probe(struct platform_device *pdev)
{
struct device *svdev;
struct snvs_secvio_drv_private *svpriv;
struct device_node *np, *npirq;
struct snvs_full __iomem *snvsregs;
int i, error;
u32 hpstate;
svpriv = kzalloc(sizeof(struct snvs_secvio_drv_private), GFP_KERNEL);
if (!svpriv)
return -ENOMEM;
svdev = &pdev->dev;
dev_set_drvdata(svdev, svpriv);
svpriv->pdev = pdev;
np = pdev->dev.of_node;
npirq = of_find_compatible_node(NULL, NULL, "fsl,imx6q-caam-secvio");
if (!npirq) {
dev_err(svdev, "can't identify secvio interrupt\n");
kfree(svpriv);
return -EINVAL;
}
svpriv->irq = irq_of_parse_and_map(npirq, 0);
if (svpriv->irq <= 0) {
kfree(svpriv);
return -EINVAL;
}
snvsregs = of_iomap(np, 0);
if (!snvsregs) {
dev_err(svdev, "register mapping failed\n");
return -ENOMEM;
}
svpriv->svregs = (struct snvs_full __force *)snvsregs;
svpriv->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(svpriv->clk)) {
dev_err(&pdev->dev, "can't get snvs clock\n");
svpriv->clk = NULL;
}
/* Device data set up. Now init interrupt source descriptions */
for (i = 0; i < MAX_SECVIO_SOURCES; i++) {
svpriv->intsrc[i].intname = violation_src_name[i];
svpriv->intsrc[i].handler = snvs_secvio_default;
}
/* Connect main handler */
for_each_possible_cpu(i)
tasklet_init(&svpriv->irqtask[i], snvs_secvio_dispatch,
(unsigned long)svdev);
error = request_irq(svpriv->irq, snvs_secvio_interrupt,
IRQF_SHARED, "snvs-secvio", svdev);
if (error) {
dev_err(svdev, "can't connect secvio interrupt\n");
irq_dispose_mapping(svpriv->irq);
svpriv->irq = 0;
iounmap(svpriv->svregs);
kfree(svpriv);
return -EINVAL;
}
clk_prepare_enable(svpriv->clk);
/*
* Configure all sources as fatal violations except LP section,
* source #5 (typically used as an external tamper detect), and
* source #3 (typically unused). Whenever the transition to
* secure mode has occurred, these will now be "fatal" violations
*/
wr_reg32(&svpriv->svregs->hp.secvio_intcfg,
HP_SECVIO_INTEN_SRC4 | HP_SECVIO_INTEN_SRC2 |
HP_SECVIO_INTEN_SRC1 | HP_SECVIO_INTEN_SRC0);
hpstate = (rd_reg32(&svpriv->svregs->hp.status) &
HP_STATUS_SSM_ST_MASK) >> HP_STATUS_SSM_ST_SHIFT;
dev_info(svdev, "violation handlers armed - %s state\n",
snvs_ssm_state_name[hpstate]);
clk_disable(svpriv->clk);
return 0;
}
static struct of_device_id snvs_secvio_match[] = {
{
.compatible = "fsl,imx6q-caam-snvs",
},
{},
};
MODULE_DEVICE_TABLE(of, snvs_secvio_match);
static struct platform_driver snvs_secvio_driver = {
.driver = {
.name = "snvs-secvio",
.owner = THIS_MODULE,
.of_match_table = snvs_secvio_match,
},
.probe = snvs_secvio_probe,
.remove = snvs_secvio_remove,
};
module_platform_driver(snvs_secvio_driver);
MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("FSL SNVS Security Violation Handler");
MODULE_AUTHOR("Freescale Semiconductor - MCU");