From 2e8726879559144b4582fa059780e452b3a1ad41 Mon Sep 17 00:00:00 2001 From: Koichiro Den Date: Mon, 16 Feb 2026 00:22:15 +0900 Subject: [PATCH] dmaengine: dw-edma: Add interrupt-emulation hooks DesignWare eDMA instances support "interrupt emulation", where a software write can assert the IRQ line without setting the normal DONE/ABORT status bits. Introduce core callbacks needed to support this feature: - .ack_emulated_irq(): core-specific sequence to deassert an emulated IRQ - .db_offset(): offset from the DMA register base that is suitable as a host-writable doorbell target for interrupt emulation Implement both hooks for the v0 register map. For dw-hdma-v0, provide a stub .db_offset() returning ~0 until the correct offset is known. The next patch wires these hooks into the dw-edma IRQ path and exports the doorbell resources to platform users. Signed-off-by: Koichiro Den Reviewed-by: Frank Li Link: https://patch.msgid.link/20260215152216.3393561-2-den@valinux.co.jp Signed-off-by: Vinod Koul --- drivers/dma/dw-edma/dw-edma-core.h | 17 +++++++++++++++++ drivers/dma/dw-edma/dw-edma-v0-core.c | 21 +++++++++++++++++++++ drivers/dma/dw-edma/dw-hdma-v0-core.c | 7 +++++++ 3 files changed, 45 insertions(+) diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h index 71894b9e0b15..59b24973fa7d 100644 --- a/drivers/dma/dw-edma/dw-edma-core.h +++ b/drivers/dma/dw-edma/dw-edma-core.h @@ -126,6 +126,8 @@ struct dw_edma_core_ops { void (*start)(struct dw_edma_chunk *chunk, bool first); void (*ch_config)(struct dw_edma_chan *chan); void (*debugfs_on)(struct dw_edma *dw); + void (*ack_emulated_irq)(struct dw_edma *dw); + resource_size_t (*db_offset)(struct dw_edma *dw); }; struct dw_edma_sg { @@ -206,4 +208,19 @@ void dw_edma_core_debugfs_on(struct dw_edma *dw) dw->core->debugfs_on(dw); } +static inline int dw_edma_core_ack_emulated_irq(struct dw_edma *dw) +{ + if (!dw->core->ack_emulated_irq) + return -EOPNOTSUPP; + + dw->core->ack_emulated_irq(dw); + return 0; +} + +static inline resource_size_t +dw_edma_core_db_offset(struct dw_edma *dw) +{ + return dw->core->db_offset(dw); +} + #endif /* _DW_EDMA_CORE_H */ diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c index b75fdaffad9a..69e8279adec8 100644 --- a/drivers/dma/dw-edma/dw-edma-v0-core.c +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c @@ -509,6 +509,25 @@ static void dw_edma_v0_core_debugfs_on(struct dw_edma *dw) dw_edma_v0_debugfs_on(dw); } +static void dw_edma_v0_core_ack_emulated_irq(struct dw_edma *dw) +{ + /* + * Interrupt emulation may assert the IRQ without setting + * DONE/ABORT status bits. A zero write to INT_CLEAR deasserts the + * emulated IRQ, while being a no-op for real interrupts. + */ + SET_BOTH_32(dw, int_clear, 0); +} + +static resource_size_t dw_edma_v0_core_db_offset(struct dw_edma *dw) +{ + /* + * rd_int_status is chosen arbitrarily, but wr_int_status would be + * equally suitable. + */ + return offsetof(struct dw_edma_v0_regs, rd_int_status); +} + static const struct dw_edma_core_ops dw_edma_v0_core = { .off = dw_edma_v0_core_off, .ch_count = dw_edma_v0_core_ch_count, @@ -517,6 +536,8 @@ static const struct dw_edma_core_ops dw_edma_v0_core = { .start = dw_edma_v0_core_start, .ch_config = dw_edma_v0_core_ch_config, .debugfs_on = dw_edma_v0_core_debugfs_on, + .ack_emulated_irq = dw_edma_v0_core_ack_emulated_irq, + .db_offset = dw_edma_v0_core_db_offset, }; void dw_edma_v0_core_register(struct dw_edma *dw) diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c index e3f8db4fe909..1ae8e44f0a67 100644 --- a/drivers/dma/dw-edma/dw-hdma-v0-core.c +++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c @@ -283,6 +283,12 @@ static void dw_hdma_v0_core_debugfs_on(struct dw_edma *dw) dw_hdma_v0_debugfs_on(dw); } +static resource_size_t dw_hdma_v0_core_db_offset(struct dw_edma *dw) +{ + /* Implement once the correct offset is known. */ + return ~0; +} + static const struct dw_edma_core_ops dw_hdma_v0_core = { .off = dw_hdma_v0_core_off, .ch_count = dw_hdma_v0_core_ch_count, @@ -291,6 +297,7 @@ static const struct dw_edma_core_ops dw_hdma_v0_core = { .start = dw_hdma_v0_core_start, .ch_config = dw_hdma_v0_core_ch_config, .debugfs_on = dw_hdma_v0_core_debugfs_on, + .db_offset = dw_hdma_v0_core_db_offset, }; void dw_hdma_v0_core_register(struct dw_edma *dw)