[PATCH v4 5/8] dmaengine: mmp_pdma: Add SpacemiT K1 PDMA support with 64-bit addressing

[Guodong Xu <guodong@riscstar.com>]

Add support for SpacemiT K1 PDMA controller which features 64-bit
addressing capabilities.

The SpacemiT K1 PDMA extends the descriptor format with additional
32-bit words for high address bits, enabling access to memory beyond
4GB boundaries. The new spacemit_k1_pdma_ops provides necessary 64-bit
address handling functions and k1 specific controller configurations.

Key changes:
- Add ARCH_SPACEMIT dependency to Kconfig
- Define new high 32-bit address registers (DDADRH, DSADRH, DTADRH)
- Add DCSR_LPAEEN bit for Long Physical Address Extension Enable
- Implement 64-bit operations for SpacemiT K1 PDMA

Signed-off-by: Guodong Xu <guodong@riscstar.com>
---
v4: No change.
v3: No change.
v2: New patch.
  - Implement 64-bit addrssing support to mmp_pdma
  - Add support for SpacemiT K1 PDMA
  - Extend the MMP_PDMA entry in Kconfig to depend on ARCH_SPACEMIT
---
 drivers/dma/Kconfig    |  2 +-
 drivers/dma/mmp_pdma.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 05c7c7d9e5a4e52a8ad7ada8c8b9b1a6f9d875f6..b8a74b1798ba1d44b26553990428c065de6fc535 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -450,7 +450,7 @@ config MILBEAUT_XDMAC
 
 config MMP_PDMA
 	tristate "MMP PDMA support"
-	depends on ARCH_MMP || ARCH_PXA || COMPILE_TEST
+	depends on ARCH_MMP || ARCH_PXA || ARCH_SPACEMIT || COMPILE_TEST
 	select DMA_ENGINE
 	help
 	  Support the MMP PDMA engine for PXA and MMP platform.
diff --git a/drivers/dma/mmp_pdma.c b/drivers/dma/mmp_pdma.c
index 610df28f429783779c1c143a13b3a829e42cf003..28c03d05e0b2708fcb8faffeeb97b97ed6fcbdc5 100644
--- a/drivers/dma/mmp_pdma.c
+++ b/drivers/dma/mmp_pdma.c
@@ -28,6 +28,9 @@
 #define DDADR(n)	(0x0200 + ((n) << 4))
 #define DSADR(n)	(0x0204 + ((n) << 4))
 #define DTADR(n)	(0x0208 + ((n) << 4))
+#define DDADRH(n)	(0x0300 + ((n) << 4))
+#define DSADRH(n)	(0x0304 + ((n) << 4))
+#define DTADRH(n)	(0x0308 + ((n) << 4))
 #define DCMD		0x020c
 
 #define DCSR_RUN	BIT(31)	/* Run Bit (read / write) */
@@ -44,6 +47,7 @@
 #define DCSR_EORSTOPEN	BIT(26)	/* STOP on an EOR */
 #define DCSR_SETCMPST	BIT(25)	/* Set Descriptor Compare Status */
 #define DCSR_CLRCMPST	BIT(24)	/* Clear Descriptor Compare Status */
+#define DCSR_LPAEEN	BIT(21)	/* Long Physical Address Extension Enable */
 #define DCSR_CMPST	BIT(10)	/* The Descriptor Compare Status */
 #define DCSR_EORINTR	BIT(9)	/* The end of Receive */
 
@@ -76,6 +80,16 @@ struct mmp_pdma_desc_hw {
 	u32 dsadr;	/* DSADR value for the current transfer */
 	u32 dtadr;	/* DTADR value for the current transfer */
 	u32 dcmd;	/* DCMD value for the current transfer */
+	/*
+	 * The following 32-bit words are only used in the 64-bit, ie.
+	 * LPAE (Long Physical Address Extension) mode.
+	 * They are used to specify the high 32 bits of the descriptor's
+	 * addresses.
+	 */
+	u32 ddadrh;	/* High 32-bit of DDADR */
+	u32 dsadrh;	/* High 32-bit of DSADR */
+	u32 dtadrh;	/* High 32-bit of DTADR */
+	u32 rsvd;	/* reserved */
 } __aligned(32);
 
 struct mmp_pdma_desc_sw {
@@ -222,6 +236,57 @@ static u64 get_desc_dst_addr_32(const struct mmp_pdma_desc_hw *desc)
 	return desc->dtadr;
 }
 
+/* For 64-bit PDMA */
+static void write_next_addr_64(struct mmp_pdma_phy *phy, dma_addr_t addr)
+{
+	writel(lower_32_bits(addr), phy->base + DDADR(phy->idx));
+	writel(upper_32_bits(addr), phy->base + DDADRH(phy->idx));
+}
+
+static u64 read_src_addr_64(struct mmp_pdma_phy *phy)
+{
+	u32 low = readl(phy->base + DSADR(phy->idx));
+	u32 high = readl(phy->base + DSADRH(phy->idx));
+
+	return ((u64)high << 32) | low;
+}
+
+static u64 read_dst_addr_64(struct mmp_pdma_phy *phy)
+{
+	u32 low = readl(phy->base + DTADR(phy->idx));
+	u32 high = readl(phy->base + DTADRH(phy->idx));
+
+	return ((u64)high << 32) | low;
+}
+
+static void set_desc_next_addr_64(struct mmp_pdma_desc_hw *desc, dma_addr_t addr)
+{
+	desc->ddadr = lower_32_bits(addr);
+	desc->ddadrh = upper_32_bits(addr);
+}
+
+static void set_desc_src_addr_64(struct mmp_pdma_desc_hw *desc, dma_addr_t addr)
+{
+	desc->dsadr = lower_32_bits(addr);
+	desc->dsadrh = upper_32_bits(addr);
+}
+
+static void set_desc_dst_addr_64(struct mmp_pdma_desc_hw *desc, dma_addr_t addr)
+{
+	desc->dtadr = lower_32_bits(addr);
+	desc->dtadrh = upper_32_bits(addr);
+}
+
+static u64 get_desc_src_addr_64(const struct mmp_pdma_desc_hw *desc)
+{
+	return ((u64)desc->dsadrh << 32) | desc->dsadr;
+}
+
+static u64 get_desc_dst_addr_64(const struct mmp_pdma_desc_hw *desc)
+{
+	return ((u64)desc->dtadrh << 32) | desc->dtadr;
+}
+
 static int mmp_pdma_config_write(struct dma_chan *dchan,
 				 struct dma_slave_config *cfg,
 				 enum dma_transfer_direction direction);
@@ -1110,10 +1175,26 @@ static const struct mmp_pdma_ops marvell_pdma_v1_ops = {
 	.dma_mask = 0,			/* let OF/platform set DMA mask */
 };
 
+static const struct mmp_pdma_ops spacemit_k1_pdma_ops = {
+	.write_next_addr = write_next_addr_64,
+	.read_src_addr = read_src_addr_64,
+	.read_dst_addr = read_dst_addr_64,
+	.set_desc_next_addr = set_desc_next_addr_64,
+	.set_desc_src_addr = set_desc_src_addr_64,
+	.set_desc_dst_addr = set_desc_dst_addr_64,
+	.get_desc_src_addr = get_desc_src_addr_64,
+	.get_desc_dst_addr = get_desc_dst_addr_64,
+	.run_bits = (DCSR_RUN | DCSR_LPAEEN),
+	.dma_mask = DMA_BIT_MASK(64),	/* force 64-bit DMA addr capability */
+};
+
 static const struct of_device_id mmp_pdma_dt_ids[] = {
 	{
 		.compatible = "marvell,pdma-1.0",
 		.data = &marvell_pdma_v1_ops
+	}, {
+		.compatible = "spacemit,k1-pdma",
+		.data = &spacemit_k1_pdma_ops
 	}, {
 		/* sentinel */
 	}

-- 
2.43.0