[PATCH v2 03/24] irqchip/renesas-rzv2h: Add DMA ACK signal routing support

John Madieu
2026-04-02T09:07:33Z

Some peripherals on RZ/G3E SoCs (SSIU, SPDIF, SCU/SRC, DVC) require
explicit ACK signal routing through the ICU via the ICU_DMACKSELk
registers for level-based DMA handshaking.

Add rzv2h_icu_register_dma_ack() to configure ICU_DMACKSELk, routing
a DMAC channel's ACK signal to the specified peripheral.

Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com>
---

Changes:

v2: No changes

drivers/irqchip/irq-renesas-rzv2h.c | 40 +++++++++++++++++++++++
include/linux/irqchip/irq-renesas-rzv2h.h | 5 +++
2 files changed, 45 insertions(+)

diff --git a/drivers/irqchip/irq-renesas-rzv2h.c b/drivers/irqchip/irq-renesas-rzv2h.c
index 330c6ae87d71..ce0cf4c4074a 100644
--- a/drivers/irqchip/irq-renesas-rzv2h.c
+++ b/drivers/irqchip/irq-renesas-rzv2h.c
@@ -151,6 +151,12 @@ struct rzv2h_hw_info {
#define ICU_DMAC_PREP_DMAREQ(sel, up) (FIELD_PREP(ICU_DMAC_DkRQ_SEL_MASK, (sel)) \
<< ICU_DMAC_DMAREQ_SHIFT(up))

+/* DMAC ACK routing - 4 x 7-bit fields per 32-bit register, 8-bit spacing */
+#define ICU_DMAC_DACK_SEL_MASK GENMASK(6, 0)
+#define ICU_DMAC_DACK_SHIFT(n) ((n) * 8)
+#define ICU_DMAC_DACK_FIELD_MASK(n) (ICU_DMAC_DACK_SEL_MASK << ICU_DMAC_DACK_SHIFT(n))
+#define ICU_DMAC_PREP_DACK(val, n) (((val) & ICU_DMAC_DACK_SEL_MASK) << ICU_DMAC_DACK_SHIFT(n))
+
/**
* struct rzv2h_icu_priv - Interrupt Control Unit controller private data structure.
* @base: Controller's base address
@@ -188,6 +194,40 @@ void rzv2h_icu_register_dma_req(struct platform_device *icu_dev, u8 dmac_index,
}
EXPORT_SYMBOL_GPL(rzv2h_icu_register_dma_req);

+/**
+ * rzv2h_icu_register_dma_ack - Configure DMA ACK signal routing
+ * @icu_dev: ICU platform device
+ * @dmac_index: DMAC instance index (0-4)
+ * @dmac_channel: DMAC channel number (0-15), or RZV2H_ICU_DMAC_ACK_NO_DEFAULT
+ * to disconnect routing for a given ack_no
+ * @ack_no: Peripheral ACK number (0-88) per RZ/G3E manual Table 4.6-28,
+ * used as index into ICU_DMACKSELk
+ *
+ * Routes the ACK signal of the peripheral identified by @ack_no to DMAC
+ * channel @dmac_channel of instance @dmac_index. When @dmac_channel is
+ * RZV2H_ICU_DMAC_ACK_NO_DEFAULT the field is reset, disconnecting any
+ * previously configured routing for that peripheral.
+ */
+void rzv2h_icu_register_dma_ack(struct platform_device *icu_dev, u8 dmac_index,
+ u8 dmac_channel, u16 ack_no)
+{
+ struct rzv2h_icu_priv *priv = platform_get_drvdata(icu_dev);
+ u8 reg_idx = ack_no / 4;
+ u8 field_idx = ack_no & 0x3;
+ u8 dmac_ack_src = (dmac_channel == RZV2H_ICU_DMAC_ACK_NO_DEFAULT) ?
+ RZV2H_ICU_DMAC_ACK_NO_DEFAULT :
+ (dmac_index * 16 + dmac_channel);
+ u32 val;
+
+ guard(raw_spinlock_irqsave)(&priv->lock);
+
+ val = readl(priv->base + ICU_DMACKSELk(reg_idx));
+ val &= ~ICU_DMAC_DACK_FIELD_MASK(field_idx);
+ val |= ICU_DMAC_PREP_DACK(dmac_ack_src, field_idx);
+ writel(val, priv->base + ICU_DMACKSELk(reg_idx));
+}
+EXPORT_SYMBOL_GPL(rzv2h_icu_register_dma_ack);
+
static inline struct rzv2h_icu_priv *irq_data_to_priv(struct irq_data *data)
{
return data->domain->host_data;
diff --git a/include/linux/irqchip/irq-renesas-rzv2h.h b/include/linux/irqchip/irq-renesas-rzv2h.h
index 618a60d2eac0..4ffa898eaaf2 100644
--- a/include/linux/irqchip/irq-renesas-rzv2h.h
+++ b/include/linux/irqchip/irq-renesas-rzv2h.h
@@ -11,13 +11,18 @@
#include <linux/platform_device.h>

#define RZV2H_ICU_DMAC_REQ_NO_DEFAULT 0x3ff
+#define RZV2H_ICU_DMAC_ACK_NO_DEFAULT 0x7f

#ifdef CONFIG_RENESAS_RZV2H_ICU
void rzv2h_icu_register_dma_req(struct platform_device *icu_dev, u8 dmac_index, u8 dmac_channel,
u16 req_no);
+void rzv2h_icu_register_dma_ack(struct platform_device *icu_dev, u8 dmac_index,
+ u8 dmac_channel, u16 ack_no);
#else
static inline void rzv2h_icu_register_dma_req(struct platform_device *icu_dev, u8 dmac_index,
u8 dmac_channel, u16 req_no) { }
+static inline void rzv2h_icu_register_dma_ack(struct platform_device *icu_dev, u8 dmac_index,
+ u8 dmac_channel, u16 ack_no) { }
#endif

#endif /* __LINUX_IRQ_RENESAS_RZV2H */
--
2.25.1