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Message-ID: <2ad03012-8a10-49fc-9e80-3b91762b9cc3@quicinc.com>
Date: Thu, 15 Aug 2024 16:30:31 -0700
From: "Abhishek Chauhan (ABC)" <quic_abchauha@...cinc.com>
To: <jitendra.vegiraju@...adcom.com>, <netdev@...r.kernel.org>
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Sagar Cheluvegowda
<quic_scheluve@...cinc.com>
Subject: Re: [net-next v4 1/5] net: stmmac: Add HDMA mapping for dw25gmac
support
On 8/14/2024 3:18 PM, jitendra.vegiraju@...adcom.com wrote:
> From: Jitendra Vegiraju <jitendra.vegiraju@...adcom.com>
>
> 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 <jitendra.vegiraju@...adcom.com>
> ---
> 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?
> +#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
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