[PATCH] irqchip/riscv-plic: fix address alignment of the plic enable bits

[Zong Li <zongbox@gmail.com>]

When the interrupt sourece id > 31, the register address is not 4 byte
alignment. Arithmetic on void pointer has no size extension, it just
add the result of 'hwirq/32' directly.

Signed-off-by: Zong Li <zongbox@gmail.com>
---
 drivers/irqchip/irq-riscv-plic.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/irqchip/irq-riscv-plic.c b/drivers/irqchip/irq-riscv-plic.c
index b5182b4..0a43763 100644
--- a/drivers/irqchip/irq-riscv-plic.c
+++ b/drivers/irqchip/irq-riscv-plic.c
@@ -92,6 +92,8 @@
  */
 #define ENABLE_BASE		0x2000
 #define ENABLE_PER_HART		0x80
+#define ENABLE_SOURCES		32
+#define ENABLE_SOURCES_OFFSET	4
 
 /*
  * Each hart context has a set of control registers associated with it.  Right
@@ -128,9 +130,10 @@ struct plic_data {
 
 /* Addressing helper functions. */
 static inline
-void __iomem *plic_enable_vector(struct plic_data *data, int contextid)
+void __iomem *plic_enable_vector(struct plic_data *data, int contextid, int hwirq)
 {
-	return data->reg + ENABLE_BASE + contextid * ENABLE_PER_HART;
+	return data->reg + ENABLE_BASE + contextid * ENABLE_PER_HART +
+		(hwirq / ENABLE_SOURCES) * ENABLE_SOURCES_OFFSET;
 }
 
 static inline
@@ -172,8 +175,8 @@ void plic_complete(struct plic_data *data, int contextid, u32 claim)
 /* Explicit interrupt masking. */
 static void plic_disable(struct plic_data *data, int contextid, int hwirq)
 {
-	void __iomem *reg = plic_enable_vector(data, contextid) + (hwirq / 32);
-	u32 mask = ~(1 << (hwirq % 32));
+	void __iomem *reg = plic_enable_vector(data, contextid, hwirq);
+	u32 mask = ~(1 << (hwirq % ENABLE_SOURCES));
 
 	spin_lock(&data->lock);
 	writel(readl(reg) & mask, reg);
@@ -182,8 +185,8 @@ static void plic_disable(struct plic_data *data, int contextid, int hwirq)
 
 static void plic_enable(struct plic_data *data, int contextid, int hwirq)
 {
-	void __iomem *reg = plic_enable_vector(data, contextid) + (hwirq / 32);
-	u32 bit = 1 << (hwirq % 32);
+	void __iomem *reg = plic_enable_vector(data, contextid, hwirq);
+	u32 bit = 1 << (hwirq % ENABLE_SOURCES);
 
 	spin_lock(&data->lock);
 	writel(readl(reg) | bit, reg);
-- 
2.7.4