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Subject[PATCH 3/5] RTC/i.MX/DryIce: monitor a security violation at runtime
Date
Maybe the unit enters the hardware related state at runtime and not at
system boot time (after a power cycle).

Signed-off-by: Juergen Borleis <jbe@pengutronix.de>
Signed-off-by: Robert Schwebel <rsc@pengutronix.de>
[rsc: got NDA clearance from Freescale]
---
drivers/rtc/rtc-imxdi.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-imxdi.c b/drivers/rtc/rtc-imxdi.c
index f8abf2b..b04c64f 100644
--- a/drivers/rtc/rtc-imxdi.c
+++ b/drivers/rtc/rtc-imxdi.c
@@ -680,6 +680,25 @@ static irqreturn_t dryice_norm_irq(int irq, void *dev_id)
irqreturn_t rc = IRQ_NONE;

dier = __raw_readl(imxdi->ioaddr + DIER);
+ dsr = __raw_readl(imxdi->ioaddr + DSR);
+
+ /* handle the security violation event */
+ if (dier & DIER_SVIE) {
+ if (dsr & DSR_SVF) {
+ /*
+ * Disable the interrupt when this kind of event has
+ * happened.
+ * There cannot be more than one event of this type,
+ * because it needs a complex state change
+ * including a main power cycle to get again out of
+ * this state.
+ */
+ di_int_disable(imxdi, DIER_SVIE);
+ /* report the violation */
+ di_report_tamper_info(imxdi, dsr);
+ rc = IRQ_HANDLED;
+ }
+ }

/* handle write complete and write error cases */
if (dier & DIER_WCIE) {
@@ -690,7 +709,6 @@ static irqreturn_t dryice_norm_irq(int irq, void *dev_id)
return rc;

/* DSR_WCF clears itself on DSR read */
- dsr = __raw_readl(imxdi->ioaddr + DSR);
if (dsr & (DSR_WCF | DSR_WEF)) {
/* mask the interrupt */
di_int_disable(imxdi, DIER_WCIE);
@@ -706,7 +724,6 @@ static irqreturn_t dryice_norm_irq(int irq, void *dev_id)
/* handle the alarm case */
if (dier & DIER_CAIE) {
/* DSR_WCF clears itself on DSR read */
- dsr = __raw_readl(imxdi->ioaddr + DSR);
if (dsr & DSR_CAF) {
/* mask the interrupt */
di_int_disable(imxdi, DIER_CAIE);
--
2.1.4


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