[PATCH v2] ptp: ocp: Fix NULL dereference in Adva board SMA sysfs operations

[Sagi Maimon <maimon.sagi@gmail.com>]

From: Sagi Maimon <sagi.maimon@adtran.com>

On Adva boards, SMA sysfs store/get operations can call
__handle_signal_outputs() or __handle_signal_inputs() while the `irig`
and `dcf` pointers are uninitialized, leading to a NULL pointer
dereference in __handle_signal() and causing a kernel crash. Adva boards
don't use `irig` or `dcf` functionality, so add Adva-specific callbacks
`ptp_ocp_sma_adva_set_outputs()` and `ptp_ocp_sma_adva_set_inputs()` that
avoid invoking `irig` or `dcf` input/output routines.

Fixes: ef61f5528fca ("ptp: ocp: add Adva timecard support")
Signed-off-by: Sagi Maimon <maimon.sagi@gmail.com>
---
Addressed comments from Vadim Fedorenko:
 - https://www.spinics.net/lists/kernel/msg5659845.html
Changes since v1:
 - Remove unused `irig` and `dcf` code.
---
---
 drivers/ptp/ptp_ocp.c | 52 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 50 insertions(+), 2 deletions(-)

diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index faf6e027f89a..2ccdca4f6960 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -2578,12 +2578,60 @@ static const struct ocp_sma_op ocp_fb_sma_op = {
 	.set_output	= ptp_ocp_sma_fb_set_output,
 };
 
+static int
+ptp_ocp_sma_adva_set_output(struct ptp_ocp *bp, int sma_nr, u32 val)
+{
+	u32 reg, mask, shift;
+	unsigned long flags;
+	u32 __iomem *gpio;
+
+	gpio = sma_nr > 2 ? &bp->sma_map1->gpio2 : &bp->sma_map2->gpio2;
+	shift = sma_nr & 1 ? 0 : 16;
+
+	mask = 0xffff << (16 - shift);
+
+	spin_lock_irqsave(&bp->lock, flags);
+
+	reg = ioread32(gpio);
+	reg = (reg & mask) | (val << shift);
+
+	iowrite32(reg, gpio);
+
+	spin_unlock_irqrestore(&bp->lock, flags);
+
+	return 0;
+}
+
+static int
+ptp_ocp_sma_adva_set_inputs(struct ptp_ocp *bp, int sma_nr, u32 val)
+{
+	u32 reg, mask, shift;
+	unsigned long flags;
+	u32 __iomem *gpio;
+
+	gpio = sma_nr > 2 ? &bp->sma_map2->gpio1 : &bp->sma_map1->gpio1;
+	shift = sma_nr & 1 ? 0 : 16;
+
+	mask = 0xffff << (16 - shift);
+
+	spin_lock_irqsave(&bp->lock, flags);
+
+	reg = ioread32(gpio);
+	reg = (reg & mask) | (val << shift);
+
+	iowrite32(reg, gpio);
+
+	spin_unlock_irqrestore(&bp->lock, flags);
+
+	return 0;
+}
+
 static const struct ocp_sma_op ocp_adva_sma_op = {
 	.tbl		= { ptp_ocp_adva_sma_in, ptp_ocp_adva_sma_out },
 	.init		= ptp_ocp_sma_fb_init,
 	.get		= ptp_ocp_sma_fb_get,
-	.set_inputs	= ptp_ocp_sma_fb_set_inputs,
-	.set_output	= ptp_ocp_sma_fb_set_output,
+	.set_inputs	= ptp_ocp_sma_adva_set_inputs,
+	.set_output	= ptp_ocp_sma_adva_set_output,
 };
 
 static int
-- 
2.47.0