Re: [PATCH v3 6/6] net: smmac: allow configuring lower pbl values

[Alexandre Torgue <alexandre.torgue@st.com>]

Hi Niklas,

On 12/07/2016 03:20 PM, Niklas Cassel wrote:
> From: Niklas Cassel <niklas.cassel@axis.com>
>
> The driver currently always sets the PBLx8/PBLx4 bit, which means that
> the pbl values configured via the pbl/txpbl/rxpbl DT properties are
> always multiplied by 8/4 in the hardware.
>
> In order to allow the DT to configure lower pbl values, while at the
> same time not changing behavior of any existing device trees using the
> pbl/txpbl/rxpbl settings, add a property to disable the multiplication
> of the pbl by 8/4 in the hardware.
>
> Suggested-by: Rabin Vincent <rabinv@axis.com>
> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>

Thanks for this patch, you can add my Acked-by.

Thanks for the whole series.

Alex

> ---
>  Documentation/devicetree/bindings/net/stmmac.txt      | 2 ++
>  Documentation/networking/stmmac.txt                   | 5 ++++-
>  drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c   | 3 ++-
>  drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c      | 3 ++-
>  drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c      | 2 ++
>  drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 1 +
>  include/linux/stmmac.h                                | 1 +
>  7 files changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/net/stmmac.txt b/Documentation/devicetree/bindings/net/stmmac.txt
> index 8080038ff1b2..128da752fec9 100644
> --- a/Documentation/devicetree/bindings/net/stmmac.txt
> +++ b/Documentation/devicetree/bindings/net/stmmac.txt
> @@ -39,6 +39,8 @@ Optional properties:
>  			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,no-pbl-x8	Don't multiply the pbl/txpbl/rxpbl values by 8.
> +			For core rev < 3.50, don't multiply the values by 4.
>  - 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 6add57374f70..2bb07078f535 100644
> --- a/Documentation/networking/stmmac.txt
> +++ b/Documentation/networking/stmmac.txt
> @@ -152,8 +152,9 @@ Where:
>   o dma_cfg: internal DMA parameters
>     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.
> +       GMAC also enables the 4xPBL by default. (8xPBL for GMAC 3.50 and newer)
>     o txpbl/rxpbl: GMAC and newer supports independent DMA pbl for tx/rx.
> +   o pblx8: Enable 8xPBL (4xPBL for core rev < 3.50). Enabled by default.
>     o fixed_burst/mixed_burst/aal
>   o clk_csr: fixed CSR Clock range selection.
>   o has_gmac: uses the GMAC core.
> @@ -208,6 +209,7 @@ struct stmmac_dma_cfg {
>  	int pbl;
>  	int txpbl;
>  	int rxpbl;
> +	bool pblx8;
>  	int fixed_burst;
>  	int mixed_burst;
>  	bool aal;
> @@ -219,6 +221,7 @@ Where:
>  	 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 pblx8: Enable 8xPBL (4xPBL for core rev < 3.50). Enabled by default.
>   o fixed_burst: program the DMA to use the fixed burst mode
>   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 99b8040af592..612d3aaac9a4 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
> @@ -98,7 +98,8 @@ static void dwmac1000_dma_init(void __iomem *ioaddr,
>  	 * Note: before stmmac core 3.50 this mode bit was 4xPBL, and
>  	 * post 3.5 mode bit acts as 8*PBL.
>  	 */
> -	value |= DMA_BUS_MODE_MAXPBL;
> +	if (dma_cfg->pblx8)
> +		value |= DMA_BUS_MODE_MAXPBL;
>  	value |= DMA_BUS_MODE_USP;
>  	value &= ~(DMA_BUS_MODE_PBL_MASK | DMA_BUS_MODE_RPBL_MASK);
>  	value |= (txpbl << DMA_BUS_MODE_PBL_SHIFT);
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
> index 2c3b2098f350..8196ab5fc33c 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
> @@ -84,7 +84,8 @@ static void dwmac4_dma_init_channel(void __iomem *ioaddr,
>  	 * on each channel
>  	 */
>  	value = readl(ioaddr + DMA_CHAN_CONTROL(channel));
> -	value = value | DMA_BUS_MODE_PBL;
> +	if (dma_cfg->pblx8)
> +		value = value | DMA_BUS_MODE_PBL;
>  	writel(value, ioaddr + DMA_CHAN_CONTROL(channel));
>
>  	value = readl(ioaddr + DMA_CHAN_TX_CONTROL(channel));
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
> index 56c8a2342c14..a2831773431a 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
> @@ -81,6 +81,7 @@ static void stmmac_default_data(struct plat_stmmacenet_data *plat)
>  	plat->mdio_bus_data->phy_mask = 0;
>
>  	plat->dma_cfg->pbl = 32;
> +	plat->dma_cfg->pblx8 = true;
>  	/* TODO: AXI */
>
>  	/* Set default value for multicast hash bins */
> @@ -115,6 +116,7 @@ static int quark_default_data(struct plat_stmmacenet_data *plat,
>  	plat->mdio_bus_data->phy_mask = 0;
>
>  	plat->dma_cfg->pbl = 16;
> +	plat->dma_cfg->pblx8 = true;
>  	plat->dma_cfg->fixed_burst = 1;
>  	/* AXI (TODO) */
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> index 96afe0561c99..082cd48db6a7 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> @@ -317,6 +317,7 @@ stmmac_probe_config_dt(struct platform_device *pdev, const char **mac)
>  		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->pblx8 = !of_property_read_bool(np, "snps,no-pbl-x8");
>
>  	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 e6d7a5940819..266dab9ad782 100644
> --- a/include/linux/stmmac.h
> +++ b/include/linux/stmmac.h
> @@ -90,6 +90,7 @@ struct stmmac_dma_cfg {
>  	int pbl;
>  	int txpbl;
>  	int rxpbl;
> +	bool pblx8;
>  	int fixed_burst;
>  	int mixed_burst;
>  	bool aal;
>