On 8/20/2024 4:10 PM, Jitendra Vegiraju wrote:

On Thu, Aug 15, 2024 at 4:30 PM Abhishek Chauhan (ABC)
[off-list ref] wrote:

quoted

On 8/14/2024 3:18 PM, jitendra.vegiraju@broadcom.com wrote:

quoted

From: Jitendra Vegiraju <redacted>

Add hdma configuration support in include/linux/stmmac.h file.
The hdma configuration includes mapping of virtual DMAs to physical DMAs.
Define a new data structure stmmac_hdma_cfg to provide the mapping.

Signed-off-by: Jitendra Vegiraju <redacted>
---
 include/linux/stmmac.h | 50 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index 338991c08f00..1775bd2b7c14 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h

@@ -89,6 +89,55 @@ struct stmmac_mdio_bus_data {
      bool needs_reset;
 };

+/* DW25GMAC Hyper-DMA Overview
+ * Hyper-DMA allows support for large number of Virtual DMA(VDMA)
+ * channels using a smaller set of physical DMA channels(PDMA).
+ * This is supported by the  mapping of VDMAs to Traffic Class (TC)
+ * and PDMA to TC in each traffic direction as shown below.
+ *
+ *        VDMAs            Traffic Class      PDMA
+ *       +--------+          +------+         +-----------+
+ *       |VDMA0   |--------->| TC0  |-------->|PDMA0/TXQ0 |
+ *TX     +--------+   |----->+------+         +-----------+
+ *Host=> +--------+   |      +------+         +-----------+ => MAC
+ *SW     |VDMA1   |---+      | TC1  |    +--->|PDMA1/TXQ1 |
+ *       +--------+          +------+    |    +-----------+
+ *       +--------+          +------+----+    +-----------+
+ *       |VDMA2   |--------->| TC2  |-------->|PDMA2/TXQ1 |
+ *       +--------+          +------+         +-----------+
+ *            .                 .                 .
+ *       +--------+          +------+         +-----------+
+ *       |VDMAn-1 |--------->| TCx-1|-------->|PDMAm/TXQm |
+ *       +--------+          +------+         +-----------+
+ *
+ *       +------+          +------+         +------+
+ *       |PDMA0 |--------->| TC0  |-------->|VDMA0 |
+ *       +------+   |----->+------+         +------+
+ *MAC => +------+   |      +------+         +------+
+ *RXQs   |PDMA1 |---+      | TC1  |    +--->|VDMA1 |  => Host
+ *       +------+          +------+    |    +------+
+ *            .                 .                 .
+ */
+
+#define STMMAC_DW25GMAC_MAX_NUM_TX_VDMA              128
+#define STMMAC_DW25GMAC_MAX_NUM_RX_VDMA              128
+
+#define STMMAC_DW25GMAC_MAX_NUM_TX_PDMA              8
+#define STMMAC_DW25GMAC_MAX_NUM_RX_PDMA              10
+

I have a query here.

Why do we need to hardcode the number of TX PDMA and RX PDMA to 8 an 10. On some platforms the number of supported TXPDMA and RXPDMA are 11 and 11 respectively ?

how do we overcome this problem, do we increase the value in such case?

Hi Abhishek,
Agreed, we can make the mapping tables more generic.
We will replace static arrays with dynamically allocated memory by
reading the TXPDMA and RXPDMA counts from hardware.
Thanks

That's a great idea. Thanks Jitendra. This way we do not have to hard code anything. 

quoted

quoted

+#define STMMAC_DW25GMAC_MAX_TC                       8
+
+/* Hyper-DMA mapping configuration
+ * Traffic Class associated with each VDMA/PDMA mapping
+ * is stored in corresponding array entry.
+ */
+struct stmmac_hdma_cfg {
+     u8 tvdma_tc[STMMAC_DW25GMAC_MAX_NUM_TX_VDMA];
+     u8 rvdma_tc[STMMAC_DW25GMAC_MAX_NUM_RX_VDMA];
+     u8 tpdma_tc[STMMAC_DW25GMAC_MAX_NUM_TX_PDMA];
+     u8 rpdma_tc[STMMAC_DW25GMAC_MAX_NUM_RX_PDMA];
+};
+
 struct stmmac_dma_cfg {
      int pbl;
      int txpbl;

@@ -101,6 +150,7 @@ struct stmmac_dma_cfg {
      bool multi_msi_en;
      bool dche;
      bool atds;
+     struct stmmac_hdma_cfg *hdma_cfg;
 };

 #define AXI_BLEN     7