Re: [PATCH v3 5/6] net: stmmac: add support for independent DMA pbl for tx/rx

[Alexandre Torgue]

Hi Niklas

On 12/07/2016 03:20 PM, Niklas Cassel wrote:
> From: Niklas Cassel <niklas.cassel@xxxxxxxx>
>
> GMAC and newer supports independent programmable burst lengths for
> DMA tx/rx. Add new optional devicetree properties representing this.
>
> To be backwards compatible, snps,pbl will still be valid, but
> snps,txpbl/snps,rxpbl will override the value in snps,pbl if set.
>
> If the IP is synthesized to use the AXI interface, there is a register
> and a matching DT property inside the optional stmmac-axi-config DT node
> for controlling burst lengths, named snps,blen.
> However, using this register, it is not possible to control tx and rx
> independently. Also, this register is not available if the IP was
> synthesized with, e.g., the AHB interface.
>
> Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxxx>

Thanks, you can add my Acked-by.

Regards
Alex

> ---
>  Documentation/devicetree/bindings/net/stmmac.txt      |  6 +++++-
>  Documentation/networking/stmmac.txt                   | 19 +++++++++++++------
>  drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c   | 12 ++++++------
>  drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c      | 12 +++++++-----
>  drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c |  2 ++
>  include/linux/stmmac.h                                |  2 ++
>  6 files changed, 35 insertions(+), 18 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/net/stmmac.txt b/Documentation/devicetree/bindings/net/stmmac.txt
> index b95ff998ba73..8080038ff1b2 100644
> --- a/Documentation/devicetree/bindings/net/stmmac.txt
> +++ b/Documentation/devicetree/bindings/net/stmmac.txt
> @@ -34,7 +34,11 @@ Optional properties:
>    platforms.
>  - tx-fifo-depth: See ethernet.txt file in the same directory
>  - rx-fifo-depth: See ethernet.txt file in the same directory
> -- snps,pbl		Programmable Burst Length
> +- snps,pbl		Programmable Burst Length (tx and rx)
> +- snps,txpbl		Tx Programmable Burst Length. Only for GMAC and newer.
> +			If set, DMA tx will use this value rather than snps,pbl.
> +- snps,rxpbl		Rx Programmable Burst Length. Only for GMAC and newer.
> +			If set, DMA rx will use this value rather than snps,pbl.
>  - snps,aal		Address-Aligned Beats
>  - snps,fixed-burst	Program the DMA to use the fixed burst mode
>  - snps,mixed-burst	Program the DMA to use the mixed burst mode
> diff --git a/Documentation/networking/stmmac.txt b/Documentation/networking/stmmac.txt
> index 014f4f756cb7..6add57374f70 100644
> --- a/Documentation/networking/stmmac.txt
> +++ b/Documentation/networking/stmmac.txt
> @@ -153,7 +153,8 @@ Where:
>     o pbl: the Programmable Burst Length is maximum number of beats to
>         be transferred in one DMA transaction.
>         GMAC also enables the 4xPBL by default.
> -   o fixed_burst/mixed_burst/burst_len
> +   o txpbl/rxpbl: GMAC and newer supports independent DMA pbl for tx/rx.
> +   o fixed_burst/mixed_burst/aal
>   o clk_csr: fixed CSR Clock range selection.
>   o has_gmac: uses the GMAC core.
>   o enh_desc: if sets the MAC will use the enhanced descriptor structure.
> @@ -205,16 +206,22 @@ tuned according to the HW capabilities.
>
>  struct stmmac_dma_cfg {
>  	int pbl;
> +	int txpbl;
> +	int rxpbl;
>  	int fixed_burst;
> -	int burst_len_supported;
> +	int mixed_burst;
> +	bool aal;
>  };
>
>  Where:
> - o pbl: Programmable Burst Length
> + o pbl: Programmable Burst Length (tx and rx)
> + o txpbl: Transmit Programmable Burst Length. Only for GMAC and newer.
> +	 If set, DMA tx will use this value rather than pbl.
> + o rxpbl: Receive Programmable Burst Length. Only for GMAC and newer.
> +	 If set, DMA rx will use this value rather than pbl.
>   o fixed_burst: program the DMA to use the fixed burst mode
> - o burst_len: this is the value we put in the register
> -	      supported values are provided as macros in
> -	      linux/stmmac.h header file.
> + o mixed_burst: program the DMA to use the mixed burst mode
> + o aal: Address-Aligned Beats
>
>  ---
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
> index 318ae9f10104..99b8040af592 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
> @@ -89,20 +89,20 @@ static void dwmac1000_dma_init(void __iomem *ioaddr,
>  			       u32 dma_tx, u32 dma_rx, int atds)
>  {
>  	u32 value = readl(ioaddr + DMA_BUS_MODE);
> +	int txpbl = dma_cfg->txpbl ?: dma_cfg->pbl;
> +	int rxpbl = dma_cfg->rxpbl ?: dma_cfg->pbl;
>
>  	/*
>  	 * Set the DMA PBL (Programmable Burst Length) mode.
>  	 *
>  	 * Note: before stmmac core 3.50 this mode bit was 4xPBL, and
>  	 * post 3.5 mode bit acts as 8*PBL.
> -	 *
> -	 * This configuration doesn't take care about the Separate PBL
> -	 * so only the bits: 13-8 are programmed with the PBL passed from the
> -	 * platform.
>  	 */
>  	value |= DMA_BUS_MODE_MAXPBL;
> -	value &= ~DMA_BUS_MODE_PBL_MASK;
> -	value |= (dma_cfg->pbl << DMA_BUS_MODE_PBL_SHIFT);
> +	value |= DMA_BUS_MODE_USP;
> +	value &= ~(DMA_BUS_MODE_PBL_MASK | DMA_BUS_MODE_RPBL_MASK);
> +	value |= (txpbl << DMA_BUS_MODE_PBL_SHIFT);
> +	value |= (rxpbl << DMA_BUS_MODE_RPBL_SHIFT);
>
>  	/* Set the Fixed burst mode */
>  	if (dma_cfg->fixed_burst)
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
> index 7d82a3464097..2c3b2098f350 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
> @@ -71,11 +71,14 @@ static void dwmac4_dma_axi(void __iomem *ioaddr, struct stmmac_axi *axi)
>  	writel(value, ioaddr + DMA_SYS_BUS_MODE);
>  }
>
> -static void dwmac4_dma_init_channel(void __iomem *ioaddr, int pbl,
> +static void dwmac4_dma_init_channel(void __iomem *ioaddr,
> +				    struct stmmac_dma_cfg *dma_cfg,
>  				    u32 dma_tx_phy, u32 dma_rx_phy,
>  				    u32 channel)
>  {
>  	u32 value;
> +	int txpbl = dma_cfg->txpbl ?: dma_cfg->pbl;
> +	int rxpbl = dma_cfg->rxpbl ?: dma_cfg->pbl;
>
>  	/* set PBL for each channels. Currently we affect same configuration
>  	 * on each channel
> @@ -85,11 +88,11 @@ static void dwmac4_dma_init_channel(void __iomem *ioaddr, int pbl,
>  	writel(value, ioaddr + DMA_CHAN_CONTROL(channel));
>
>  	value = readl(ioaddr + DMA_CHAN_TX_CONTROL(channel));
> -	value = value | (pbl << DMA_BUS_MODE_PBL_SHIFT);
> +	value = value | (txpbl << DMA_BUS_MODE_PBL_SHIFT);
>  	writel(value, ioaddr + DMA_CHAN_TX_CONTROL(channel));
>
>  	value = readl(ioaddr + DMA_CHAN_RX_CONTROL(channel));
> -	value = value | (pbl << DMA_BUS_MODE_RPBL_SHIFT);
> +	value = value | (rxpbl << DMA_BUS_MODE_RPBL_SHIFT);
>  	writel(value, ioaddr + DMA_CHAN_RX_CONTROL(channel));
>
>  	/* Mask interrupts by writing to CSR7 */
> @@ -120,8 +123,7 @@ static void dwmac4_dma_init(void __iomem *ioaddr,
>  	writel(value, ioaddr + DMA_SYS_BUS_MODE);
>
>  	for (i = 0; i < DMA_CHANNEL_NB_MAX; i++)
> -		dwmac4_dma_init_channel(ioaddr, dma_cfg->pbl,
> -					dma_tx, dma_rx, i);
> +		dwmac4_dma_init_channel(ioaddr, dma_cfg, dma_tx, dma_rx, i);
>  }
>
>  static void _dwmac4_dump_dma_regs(void __iomem *ioaddr, u32 channel)
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> index 81800f23a9c4..96afe0561c99 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> @@ -315,6 +315,8 @@ stmmac_probe_config_dt(struct platform_device *pdev, const char **mac)
>  	of_property_read_u32(np, "snps,pbl", &dma_cfg->pbl);
>  	if (!dma_cfg->pbl)
>  		dma_cfg->pbl = DEFAULT_DMA_PBL;
> +	of_property_read_u32(np, "snps,txpbl", &dma_cfg->txpbl);
> +	of_property_read_u32(np, "snps,rxpbl", &dma_cfg->rxpbl);
>
>  	dma_cfg->aal = of_property_read_bool(np, "snps,aal");
>  	dma_cfg->fixed_burst = of_property_read_bool(np, "snps,fixed-burst");
> diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
> index 3537fb33cc90..e6d7a5940819 100644
> --- a/include/linux/stmmac.h
> +++ b/include/linux/stmmac.h
> @@ -88,6 +88,8 @@ struct stmmac_mdio_bus_data {
>
>  struct stmmac_dma_cfg {
>  	int pbl;
> +	int txpbl;
> +	int rxpbl;
>  	int fixed_burst;
>  	int mixed_burst;
>  	bool aal;