Re: [net-next v4 1/5] net: stmmac: Add HDMA mapping for dw25gmac support
From: Abhishek Chauhan (ABC) <hidden>
Date: 2024-08-15 23:31:33
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bpf, linux-arm-kernel, lkml
On 8/14/2024 3:18 PM, jitendra.vegiraju@broadcom.com wrote:
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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?
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+#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