[PATCH v4 7/8] dmaengine: dw-edma: add flags at struct dw_edma_chip

[Frank Li <Frank.Li@nxp.com>]

Allow PCI EP probe DMA locally and prevent use of remote MSI
to remote PCI host.

Add option to force 32bit DBI register access even on
64-bit systems. i.MX8 hardware only allowed 32bit register
access.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Change from v3 to v4
 - None
Change from v2 to v3
 - rework commit message
 - Change to DW_EDMA_CHIP_32BIT_DBI
 - using DW_EDMA_CHIP_LOCAL control msi
 - Apply Bjorn's comments,
        if (!j) {
               control |= DW_EDMA_V0_LIE;
               if (!(chan->chip->flags & DW_EDMA_CHIP_LOCAL))
                               control |= DW_EDMA_V0_RIE;
        }

        if ((chan->chip->flags & DW_EDMA_CHIP_REG32BIT) ||
              !IS_ENABLED(CONFIG_64BIT)) {
          SET_CH_32(...);
          SET_CH_32(...);
       } else {
          SET_CH_64(...);
       }


Change from v1 to v2
- none
 drivers/dma/dw-edma/dw-edma-v0-core.c | 20 ++++++++++++--------
 include/linux/dma/edma.h              |  9 +++++++++
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
index 35f2adac93e46..00a00d68d44e7 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
@@ -301,6 +301,7 @@ u32 dw_edma_v0_core_status_abort_int(struct dw_edma *dw, enum dw_edma_dir dir)
 static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
 {
 	struct dw_edma_burst *child;
+	struct dw_edma_chan *chan = chunk->chan;
 	struct dw_edma_v0_lli __iomem *lli;
 	struct dw_edma_v0_llp __iomem *llp;
 	u32 control = 0, i = 0;
@@ -314,9 +315,11 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
 	j = chunk->bursts_alloc;
 	list_for_each_entry(child, &chunk->burst->list, list) {
 		j--;
-		if (!j)
-			control |= (DW_EDMA_V0_LIE | DW_EDMA_V0_RIE);
-
+		if (!j) {
+			control |= DW_EDMA_V0_LIE;
+			if (!(chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL))
+				control |= DW_EDMA_V0_RIE;
+		}
 		/* Channel control */
 		SET_LL_32(&lli[i].control, control);
 		/* Transfer size */
@@ -414,15 +417,16 @@ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
 		SET_CH_32(dw, chan->dir, chan->id, ch_control1,
 			  (DW_EDMA_V0_CCS | DW_EDMA_V0_LLE));
 		/* Linked list */
-		#ifdef CONFIG_64BIT
-			SET_CH_64(dw, chan->dir, chan->id, llp.reg,
-				  chunk->ll_region.paddr);
-		#else /* CONFIG_64BIT */
+		if ((chan->dw->chip->flags & DW_EDMA_CHIP_32BIT_DBI) ||
+		    !IS_ENABLED(CONFIG_64BIT)) {
 			SET_CH_32(dw, chan->dir, chan->id, llp.lsb,
 				  lower_32_bits(chunk->ll_region.paddr));
 			SET_CH_32(dw, chan->dir, chan->id, llp.msb,
 				  upper_32_bits(chunk->ll_region.paddr));
-		#endif /* CONFIG_64BIT */
+		} else {
+			SET_CH_64(dw, chan->dir, chan->id, llp.reg,
+				  chunk->ll_region.paddr);
+		}
 	}
 	/* Doorbell */
 	SET_RW_32(dw, chan->dir, doorbell,
diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
index c2039246fc08c..eea11b1d9e688 100644
--- a/include/linux/dma/edma.h
+++ b/include/linux/dma/edma.h
@@ -33,6 +33,12 @@ enum dw_edma_map_format {
 	EDMA_MF_HDMA_COMPAT = 0x5
 };
 
+/* Probe EDMA engine locally and prevent generate MSI to host side*/
+#define DW_EDMA_CHIP_LOCAL	BIT(0)
+
+/* Only support 32bit DBI register access */
+#define DW_EDMA_CHIP_32BIT_DBI	BIT(1)
+
 /**
  * struct dw_edma_chip - representation of DesignWare eDMA controller hardware
  * @dev:		 struct device of the eDMA controller
@@ -40,6 +46,8 @@ enum dw_edma_map_format {
  * @nr_irqs:		 total dma irq number
  * @ops			 DMA channel to IRQ number mapping
  * @reg_base		 DMA register base address
+ * @flags		   - DW_EDMA_CHIP_LOCAL
+ *			   - DW_EDMA_CHIP_32BIT_DBI
  * @ll_wr_cnt		 DMA write link list number
  * @ll_rd_cnt		 DMA read link list number
  * @rg_region		 DMA register region
@@ -53,6 +61,7 @@ struct dw_edma_chip {
 	int			id;
 	int			nr_irqs;
 	const struct dw_edma_core_ops   *ops;
+	u32			flags;
 
 	void __iomem		*reg_base;
 
-- 
2.24.0.rc1