OMAPDSS: fix shared irq handlers
DSS uses shared irq handlers for DISPC and DSI, because on OMAP3, the
DISPC and DSI share the same irq line.
However, the irq handlers presume that the hardware is enabled, which,
in theory, may not be the case with shared irq handlers. So if an
interrupt happens while the DISPC/DSI is off, the kernel will halt as
the irq handler tries to access the DISPC/DSI registers.
In practice that should never happen, as both DSI and DISPC are in the
same power domain. So if there's an IRQ for one of them, the other is
also enabled. However, if CONFIG_DEBUG_SHIRQ is enabled, the kernel will
generate a spurious IRQ, which then causes the problem.
This patch adds an is_enabled field for both DISPC and DSI, which is
used to track if the HW is enabled. For DISPC the code is slightly more
complex, as the users of DISPC can register the interrupt handler, and
we want to hide the is_enabled handling from the users of DISPC.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/video/omap2/dss/dsi.c b/drivers/video/omap2/dss/dsi.c
index 121d104..8be9b04 100644
--- a/drivers/video/omap2/dss/dsi.c
+++ b/drivers/video/omap2/dss/dsi.c
@@ -297,6 +297,8 @@
int irq;
+ bool is_enabled;
+
struct clk *dss_clk;
struct clk *sys_clk;
@@ -795,6 +797,9 @@
dsidev = (struct platform_device *) arg;
dsi = dsi_get_dsidrv_data(dsidev);
+ if (!dsi->is_enabled)
+ return IRQ_NONE;
+
spin_lock(&dsi->irq_lock);
irqstatus = dsi_read_reg(dsidev, DSI_IRQSTATUS);
@@ -5671,6 +5676,15 @@
static int dsi_runtime_suspend(struct device *dev)
{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct dsi_data *dsi = dsi_get_dsidrv_data(pdev);
+
+ dsi->is_enabled = false;
+ /* ensure the irq handler sees the is_enabled value */
+ smp_wmb();
+ /* wait for current handler to finish before turning the DSI off */
+ synchronize_irq(dsi->irq);
+
dispc_runtime_put();
return 0;
@@ -5678,12 +5692,18 @@
static int dsi_runtime_resume(struct device *dev)
{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct dsi_data *dsi = dsi_get_dsidrv_data(pdev);
int r;
r = dispc_runtime_get();
if (r)
return r;
+ dsi->is_enabled = true;
+ /* ensure the irq handler sees the is_enabled value */
+ smp_wmb();
+
return 0;
}