[RFC][PATCH][POWERPC] QEIC: Implement pluggable handlers, fix MPIC cascading

[Anton Vorontsov <avorontsov@ru.mvista.com>]

On Wed, Oct 03, 2007 at 08:02:42AM +1000, Benjamin Herrenschmidt wrote:
> 
> > 
> > Exactly, this is what that patch is trying to do. QEIC cascade handler is
> > calling mpic's eoi() (end() actually, as it's flow level, but end == eoi.
> > Is it main objection? Ok, I can get rid of it, and use chip level eoi()
> > directly).
> 
> Yes, use eoi() directly, don't add end()

Ok.

> > Yup, exactly. Actually, QEIC's cascade handlers do not really know
> > what needs to be done, but they're good at guessing (if (chip->eoi)).
> > 
> > Sure, I can place board-specific QEIC handlers in the board file, but
> > that will be quite big code duplication for all machines using QEIC.
> 
> Maybe you can provide a set of common ones, and then just pick the one
> you want from the board file ?
> 
> Or have some board code call into a QEIC init routine specifying the
> type of cascade handler to use ... or whatevre you like here.

Ok, thanks. How about this patch?

- - - -
From: Anton Vorontsov <avorontsov@ru.mvista.com>
Subject: [PATCH] [POWERPC] QEIC: Implement pluggable handlers, fix MPIC cascading

set_irq_chained_handler overwrites MPIC's handle_irq function
(handle_fasteoi_irq) thus MPIC never gets eoi event from the
cascaded IRQ. This situation hangs MPIC on MPC8568E.

To solve this problem efficiently, QEIC needs pluggable handlers,
specific to the underlaying interrupt controller.

Patch extends qe_ic_init() function to accept low and high interrupt
handlers. To avoid #ifdefs, stack of interrupt handlers specified in
the header file and functions are marked 'static inline', thus
handlers are compiled-in only if actually used (in the board file).
Another option would be to lookup for parent controller and
automatically detect handlers, but this will waste text size because
of never used handlers.

qe_ic_init() also changed in regard to support multiplexed high/low
lines as found in MPC8568E-MDS, plus qe_ic_cascade_muxed_mpic()
handler implemented appropriately.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
---
 arch/powerpc/platforms/83xx/mpc832x_mds.c |    2 +-
 arch/powerpc/platforms/83xx/mpc832x_rdb.c |    2 +-
 arch/powerpc/platforms/83xx/mpc836x_mds.c |    2 +-
 arch/powerpc/platforms/85xx/mpc85xx_mds.c |    2 +-
 arch/powerpc/sysdev/qe_lib/qe_ic.c        |   29 +++---------
 include/asm-powerpc/qe_ic.h               |   68 ++++++++++++++++++++++++++++-
 6 files changed, 78 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/platforms/83xx/mpc832x_mds.c b/arch/powerpc/platforms/83xx/mpc832x_mds.c
index d494bc4..95f32ca 100644
--- a/arch/powerpc/platforms/83xx/mpc832x_mds.c
+++ b/arch/powerpc/platforms/83xx/mpc832x_mds.c
@@ -140,7 +140,7 @@ static void __init mpc832x_sys_init_IRQ(void)
 	if (!np)
 		return;
 
-	qe_ic_init(np, 0);
+	qe_ic_init(np, 0, qe_ic_cascade_low_ipic, qe_ic_cascade_high_ipic);
 	of_node_put(np);
 #endif				/* CONFIG_QUICC_ENGINE */
 }
diff --git a/arch/powerpc/platforms/83xx/mpc832x_rdb.c b/arch/powerpc/platforms/83xx/mpc832x_rdb.c
index 24a790c..f842a1c 100644
--- a/arch/powerpc/platforms/83xx/mpc832x_rdb.c
+++ b/arch/powerpc/platforms/83xx/mpc832x_rdb.c
@@ -151,7 +151,7 @@ void __init mpc832x_rdb_init_IRQ(void)
 	if (!np)
 		return;
 
-	qe_ic_init(np, 0);
+	qe_ic_init(np, 0, qe_ic_cascade_low_ipic, qe_ic_cascade_high_ipic);
 	of_node_put(np);
 #endif				/* CONFIG_QUICC_ENGINE */
 }
diff --git a/arch/powerpc/platforms/83xx/mpc836x_mds.c b/arch/powerpc/platforms/83xx/mpc836x_mds.c
index db69576..5971fe6 100644
--- a/arch/powerpc/platforms/83xx/mpc836x_mds.c
+++ b/arch/powerpc/platforms/83xx/mpc836x_mds.c
@@ -147,7 +147,7 @@ static void __init mpc836x_mds_init_IRQ(void)
 	if (!np)
 		return;
 
-	qe_ic_init(np, 0);
+	qe_ic_init(np, 0, qe_ic_cascade_low_ipic, qe_ic_cascade_high_ipic);
 	of_node_put(np);
 #endif				/* CONFIG_QUICC_ENGINE */
 }
diff --git a/arch/powerpc/platforms/85xx/mpc85xx_mds.c b/arch/powerpc/platforms/85xx/mpc85xx_mds.c
index c379286..69c177b 100644
--- a/arch/powerpc/platforms/85xx/mpc85xx_mds.c
+++ b/arch/powerpc/platforms/85xx/mpc85xx_mds.c
@@ -174,7 +174,7 @@ static void __init mpc85xx_mds_pic_init(void)
 	if (!np)
 		return;
 
-	qe_ic_init(np, 0);
+	qe_ic_init(np, 0, qe_ic_cascade_muxed_mpic, NULL);
 	of_node_put(np);
 #endif				/* CONFIG_QUICC_ENGINE */
 }
diff --git a/arch/powerpc/sysdev/qe_lib/qe_ic.c b/arch/powerpc/sysdev/qe_lib/qe_ic.c
index 9a2d1ed..e1c0fd6 100644
--- a/arch/powerpc/sysdev/qe_lib/qe_ic.c
+++ b/arch/powerpc/sysdev/qe_lib/qe_ic.c
@@ -321,25 +321,9 @@ unsigned int qe_ic_get_high_irq(struct qe_ic *qe_ic)
 	return irq_linear_revmap(qe_ic->irqhost, irq);
 }
 
-void qe_ic_cascade_low(unsigned int irq, struct irq_desc *desc)
-{
-	struct qe_ic *qe_ic = desc->handler_data;
-	unsigned int cascade_irq = qe_ic_get_low_irq(qe_ic);
-
-	if (cascade_irq != NO_IRQ)
-		generic_handle_irq(cascade_irq);
-}
-
-void qe_ic_cascade_high(unsigned int irq, struct irq_desc *desc)
-{
-	struct qe_ic *qe_ic = desc->handler_data;
-	unsigned int cascade_irq = qe_ic_get_high_irq(qe_ic);
-
-	if (cascade_irq != NO_IRQ)
-		generic_handle_irq(cascade_irq);
-}
-
-void __init qe_ic_init(struct device_node *node, unsigned int flags)
+void __init qe_ic_init(struct device_node *node, unsigned int flags,
+		void (*low_handler)(unsigned int irq, struct irq_desc *desc),
+		void (*high_handler)(unsigned int irq, struct irq_desc *desc))
 {
 	struct qe_ic *qe_ic;
 	struct resource res;
@@ -399,11 +383,12 @@ void __init qe_ic_init(struct device_node *node, unsigned int flags)
 	qe_ic_write(qe_ic->regs, QEIC_CICR, temp);
 
 	set_irq_data(qe_ic->virq_low, qe_ic);
-	set_irq_chained_handler(qe_ic->virq_low, qe_ic_cascade_low);
+	set_irq_chained_handler(qe_ic->virq_low, low_handler);
 
-	if (qe_ic->virq_high != NO_IRQ) {
+	if (qe_ic->virq_high != NO_IRQ &&
+			qe_ic->virq_high != qe_ic->virq_low) {
 		set_irq_data(qe_ic->virq_high, qe_ic);
-		set_irq_chained_handler(qe_ic->virq_high, qe_ic_cascade_high);
+		set_irq_chained_handler(qe_ic->virq_high, high_handler);
 	}
 }
 
diff --git a/include/asm-powerpc/qe_ic.h b/include/asm-powerpc/qe_ic.h
index e386fb7..a779b2c 100644
--- a/include/asm-powerpc/qe_ic.h
+++ b/include/asm-powerpc/qe_ic.h
@@ -56,9 +56,75 @@ enum qe_ic_grp_id {
 	QE_IC_GRP_RISCB		/* QE interrupt controller RISC group B */
 };
 
-void qe_ic_init(struct device_node *node, unsigned int flags);
+void qe_ic_init(struct device_node *node, unsigned int flags,
+		void (*low_handler)(unsigned int irq, struct irq_desc *desc),
+		void (*high_handler)(unsigned int irq, struct irq_desc *desc));
 void qe_ic_set_highest_priority(unsigned int virq, int high);
 int qe_ic_set_priority(unsigned int virq, unsigned int priority);
 int qe_ic_set_high_priority(unsigned int virq, unsigned int priority, int high);
 
+struct qe_ic;
+unsigned int qe_ic_get_low_irq(struct qe_ic *qe_ic);
+unsigned int qe_ic_get_high_irq(struct qe_ic *qe_ic);
+
+static inline void qe_ic_cascade_low_ipic(unsigned int irq,
+					  struct irq_desc *desc)
+{
+	struct qe_ic *qe_ic = desc->handler_data;
+	unsigned int cascade_irq = qe_ic_get_low_irq(qe_ic);
+
+	if (cascade_irq != NO_IRQ)
+		generic_handle_irq(cascade_irq);
+}
+
+static inline void qe_ic_cascade_high_ipic(unsigned int irq,
+					   struct irq_desc *desc)
+{
+	struct qe_ic *qe_ic = desc->handler_data;
+	unsigned int cascade_irq = qe_ic_get_high_irq(qe_ic);
+
+	if (cascade_irq != NO_IRQ)
+		generic_handle_irq(cascade_irq);
+}
+
+static inline void qe_ic_cascade_low_mpic(unsigned int irq,
+					  struct irq_desc *desc)
+{
+	struct qe_ic *qe_ic = desc->handler_data;
+	unsigned int cascade_irq = qe_ic_get_low_irq(qe_ic);
+
+	if (cascade_irq != NO_IRQ)
+		generic_handle_irq(cascade_irq);
+
+	desc->chip->eoi(irq);
+}
+
+static inline void qe_ic_cascade_high_mpic(unsigned int irq,
+					   struct irq_desc *desc)
+{
+	struct qe_ic *qe_ic = desc->handler_data;
+	unsigned int cascade_irq = qe_ic_get_high_irq(qe_ic);
+
+	if (cascade_irq != NO_IRQ)
+		generic_handle_irq(cascade_irq);
+
+	desc->chip->eoi(irq);
+}
+
+static inline void qe_ic_cascade_muxed_mpic(unsigned int irq,
+					    struct irq_desc *desc)
+{
+	struct qe_ic *qe_ic = desc->handler_data;
+	unsigned int cascade_irq;
+
+	cascade_irq = qe_ic_get_high_irq(qe_ic);
+	if (cascade_irq == NO_IRQ)
+		cascade_irq = qe_ic_get_low_irq(qe_ic);
+
+	if (cascade_irq != NO_IRQ)
+		generic_handle_irq(cascade_irq);
+
+	desc->chip->eoi(irq);
+}
+
 #endif /* _ASM_POWERPC_QE_IC_H */
-- 
1.5.0.6