[PATCh v3 0/2] Add DMA ACK signal routing for RZ/V2H family

[PATCh v3 0/2] Add DMA ACK signal routing for RZ/V2H family

[John Madieu]

Some peripherals on RZ/V2H, RZ/V2N, and RZ/G3E SoCs require explicit
DMA ACK signal routing through the ICU for level-based DMA handshaking.

Rather than encoding the ACK signal number as a second DMA specifier
cell, derive it in-driver from the MID/RID request number using
arithmetic formulas based on ICU Table 4.6-28 (3 linear peripheral
groups). It must also be noted that DMA ack register is located in
the ICU block


This series adds:
  - ICU driver extension to register/deregister DMA ACK signals
    (DMA ACK register is located in the ICU block)
  - rz-dmac driver support for ACK signal routing via MID/RID lookup,
    including restore on system resume

Note: patch 2/2 depends upon [1], the Cyclic DMA series from Claudiu.

Changes:

v3:
 - Splitout from v2 [2] into DMA-specific series 
 - No code change

v2:
 - Drop DMA ACK second cell from DT specifier
 - Derive ACK signal number in-driver from MID/RID using arithmetic
   formulas per ICU Table 4.6-28 (3 linear peripheral groups)

[1] https://lore.kernel.org/all/20260320112838.2200198-1-claudiu.beznea.uj@bp.renesas.com/
[2] https://lore.kernel.org/all/20260402090524.9137-1-john.madieu.xa@bp.renesas.com/

John Madieu (2):
  irqchip/renesas-rzv2h: Add DMA ACK signal routing support
  dma: sh: rz-dmac: Add DMA ACK signal routing support

 drivers/dma/sh/rz-dmac.c                  | 72 +++++++++++++++++++++++
 drivers/irqchip/irq-renesas-rzv2h.c       | 40 +++++++++++++
 include/linux/irqchip/irq-renesas-rzv2h.h |  5 ++
 3 files changed, 117 insertions(+)

-- 
2.25.1

[PATCh v3 1/2] irqchip/renesas-rzv2h: Add DMA ACK signal routing support

[John Madieu]

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:

v3: No 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 31f191641ff8..4ebcb91c0b6c 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

Re: [PATCh v3 1/2] irqchip/renesas-rzv2h: Add DMA ACK signal routing support

[Thomas Gleixner]

On Thu, Apr 02 2026 at 18:22, John Madieu wrote:
> 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>

Assuming this goes through the DMA tree:

Acked-by: Thomas Gleixner <tglx@kernel.org>

[PATCh v3 2/2] dma: sh: rz-dmac: Add DMA ACK signal routing support

[John Madieu]

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

Rather than extending the DT binding with an optional second #dma-cells
(which would require all DMA consumers to supply two cells even when ACK
routing is not needed), derive the ACK signal number directly from the
MID/RID request number using the linear mapping defined in RZ/G3E hardware
manual Table 4.6-28:

  PFC external DMA pins (DREQ0..DREQ4):
    req_no 0x000-0x004 -> ACK No. 84-88

  SSIU BUSIFs (ssip00..ssip93):
    req_no 0x161-0x198 -> ACK No. 28-83

  SPDIF (CH0..CH2) + SCU SRC (sr0..sr9) + DVC (cmd0..cmd1):
    req_no 0x199-0x1b4 -> ACK No. 0-27

ACK routing is programmed when a channel is prepared for transfer and
cleared when the channel is released or the transfer times out, following
the same pattern as MID/RID request routing.

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

Changes:

v3: No changes

v2:
 - Drop DMA ACK second cell from DT specifier
 - Derive ACK signal number in-driver from MID/RID using arithmetic formulas
   per ICU Table 4.6-28 (3 linear peripheral groups)

 drivers/dma/sh/rz-dmac.c | 72 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index 95a89c9d2925..bde3da96b37e 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -97,6 +97,7 @@ struct rz_dmac_chan {
 	u32 chcfg;
 	u32 chctrl;
 	int mid_rid;
+	int dmac_ack;
 
 	struct {
 		u32 nxla;
@@ -124,6 +125,9 @@ struct rz_dmac_icu {
 struct rz_dmac_info {
 	void (*icu_register_dma_req)(struct platform_device *icu_dev,
 				     u8 dmac_index, u8 dmac_channel, u16 req_no);
+	void (*icu_register_dma_ack)(struct platform_device *icu_dev,
+				     u8 dmac_index, u8 dmac_channel, u16 ack_no);
+	u16 default_dma_ack_no;
 	u16 default_dma_req_no;
 };
 
@@ -362,6 +366,60 @@ static void rz_dmac_set_dma_req_no(struct rz_dmac *dmac, unsigned int index,
 		rz_dmac_set_dmars_register(dmac, index, req_no);
 }
 
+/*
+ * Map MID/RID request number (bits[0:9] of DMA specifier) to the ICU
+ * DMA ACK signal number, per RZ/G3E hardware manual Table 4.6-28.
+ *
+ * Three peripheral groups cover all ACK-capable peripherals:
+ *
+ *   PFC external DMA pins (DREQ0..DREQ4):
+ *     req_no 0x000-0x004 -> ACK No. 84-88  (ack = req_no + 84)
+ *
+ *   SSIU BUSIFs (ssip00..ssip93):
+ *     req_no 0x161-0x198 -> ACK No. 28-83  (ack = req_no - 0x145)
+ *
+ *   SPDIF (CH0..CH2) + SCU SRC (sr0..sr9) + DVC (cmd0..cmd1):
+ *     req_no 0x199-0x1b4 -> ACK No. 0-27   (ack = req_no - 0x199)
+ */
+static int rz_dmac_get_ack_no(const struct rz_dmac_info *info, u16 req_no)
+{
+	if (!info->icu_register_dma_ack)
+		return -EINVAL;
+
+	switch (req_no) {
+	case 0x000 ... 0x004:
+		/* PFC external DMA pins: ACK No. 84-88 */
+		return req_no + 84;
+	case 0x161 ... 0x198:
+		/* SSIU BUSIFs: ACK No. 28-83 */
+		return req_no - 0x145;
+	case 0x199 ... 0x1b4:
+		/* SPDIF + SCU SRC + DVC: ACK No. 0-27 */
+		return req_no - 0x199;
+	default:
+		return -EINVAL;
+	}
+}
+
+static void rz_dmac_set_dma_ack_no(struct rz_dmac *dmac, unsigned int index,
+				   int ack_no)
+{
+	if (ack_no < 0 || !dmac->info->icu_register_dma_ack)
+		return;
+
+	dmac->info->icu_register_dma_ack(dmac->icu.pdev, dmac->icu.dmac_index,
+					 index, ack_no);
+}
+
+static void rz_dmac_reset_dma_ack_no(struct rz_dmac *dmac, int ack_no)
+{
+	if (ack_no < 0 || !dmac->info->icu_register_dma_ack)
+		return;
+
+	dmac->info->icu_register_dma_ack(dmac->icu.pdev, dmac->icu.dmac_index,
+					 dmac->info->default_dma_ack_no, ack_no);
+}
+
 static void rz_dmac_prepare_desc_for_memcpy(struct rz_dmac_chan *channel)
 {
 	struct dma_chan *chan = &channel->vc.chan;
@@ -431,6 +489,7 @@ static void rz_dmac_prepare_descs_for_slave_sg(struct rz_dmac_chan *channel)
 	channel->lmdesc.tail = lmdesc;
 
 	rz_dmac_set_dma_req_no(dmac, channel->index, channel->mid_rid);
+	rz_dmac_set_dma_ack_no(dmac, channel->index, channel->dmac_ack);
 }
 
 static void rz_dmac_prepare_descs_for_cyclic(struct rz_dmac_chan *channel)
@@ -485,6 +544,7 @@ static void rz_dmac_prepare_descs_for_cyclic(struct rz_dmac_chan *channel)
 	channel->lmdesc.tail = lmdesc;
 
 	rz_dmac_set_dma_req_no(dmac, channel->index, channel->mid_rid);
+	rz_dmac_set_dma_ack_no(dmac, channel->index, channel->dmac_ack);
 }
 
 static int rz_dmac_xfer_desc(struct rz_dmac_chan *chan)
@@ -567,6 +627,9 @@ static void rz_dmac_free_chan_resources(struct dma_chan *chan)
 		channel->mid_rid = -EINVAL;
 	}
 
+	rz_dmac_reset_dma_ack_no(dmac, channel->dmac_ack);
+	channel->dmac_ack = -EINVAL;
+
 	spin_unlock_irqrestore(&channel->vc.lock, flags);
 
 	list_for_each_entry_safe(desc, _desc, &channel->ld_free, node) {
@@ -814,6 +877,7 @@ static void rz_dmac_device_synchronize(struct dma_chan *chan)
 		dev_warn(dmac->dev, "DMA Timeout");
 
 	rz_dmac_set_dma_req_no(dmac, channel->index, dmac->info->default_dma_req_no);
+	rz_dmac_reset_dma_ack_no(dmac, channel->dmac_ack);
 }
 
 static struct rz_lmdesc *
@@ -1164,6 +1228,8 @@ static bool rz_dmac_chan_filter(struct dma_chan *chan, void *arg)
 	channel->chcfg = CHCFG_FILL_TM(ch_cfg) | CHCFG_FILL_AM(ch_cfg) |
 			 CHCFG_FILL_LVL(ch_cfg) | CHCFG_FILL_HIEN(ch_cfg);
 
+	channel->dmac_ack = rz_dmac_get_ack_no(dmac->info, channel->mid_rid);
+
 	return !test_and_set_bit(channel->mid_rid, dmac->modules);
 }
 
@@ -1200,6 +1266,7 @@ static int rz_dmac_chan_probe(struct rz_dmac *dmac,
 
 	channel->index = index;
 	channel->mid_rid = -EINVAL;
+	channel->dmac_ack = -EINVAL;
 
 	/* Request the channel interrupt. */
 	scnprintf(pdev_irqname, sizeof(pdev_irqname), "ch%u", index);
@@ -1569,6 +1636,9 @@ static int rz_dmac_resume(struct device *dev)
 
 		guard(spinlock_irqsave)(&channel->vc.lock);
 
+		rz_dmac_set_dma_req_no(dmac, channel->index, channel->mid_rid);
+		rz_dmac_set_dma_ack_no(dmac, channel->index, channel->dmac_ack);
+
 		if (!(channel->status & BIT(RZ_DMAC_CHAN_STATUS_CYCLIC))) {
 			rz_dmac_ch_writel(&dmac->channels[i], CHCTRL_DEFAULT, CHCTRL, 1);
 			continue;
@@ -1601,6 +1671,8 @@ static const struct dev_pm_ops rz_dmac_pm_ops = {
 
 static const struct rz_dmac_info rz_dmac_v2h_info = {
 	.icu_register_dma_req = rzv2h_icu_register_dma_req,
+	.icu_register_dma_ack = rzv2h_icu_register_dma_ack,
+	.default_dma_ack_no = RZV2H_ICU_DMAC_ACK_NO_DEFAULT,
 	.default_dma_req_no = RZV2H_ICU_DMAC_REQ_NO_DEFAULT,
 };
 
-- 
2.25.1