[PATCH v2] net: macb: add SiFive support

[Sascha Hauer]

On Mon, May 31, 2021 at 08:58:15AM +0200, Ahmad Fatoum wrote:
> The Ethernet controller on the SiFive SoCs needs some special TX clock
> setup. Port the relevant Linux v5.12 bits to enable it.
> 
> As the macb driver is used for some old at91 boards that aren't yet
> ported to the common clock framework, that new setup code has to be
> in an #ifdef.
> 
> Tested on qemu-system-riscv64 -M sifive_u with dhcp.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> ---
> v1 -> v2: add common clock code into #ifdef
> ---
>  drivers/net/macb.c | 120 +++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 120 insertions(+)

Applied, thanks

Sascha

> 
> diff --git a/drivers/net/macb.c b/drivers/net/macb.c
> index 14a0b45322bf..19ae64d7a5a2 100644
> --- a/drivers/net/macb.c
> +++ b/drivers/net/macb.c
> @@ -52,6 +52,17 @@
>  #define TX_RING_BYTES		(sizeof(struct macb_dma_desc) * TX_RING_SIZE)
>  #define GEM_Q1_DESC_BYTES	(sizeof(struct macb_dma_desc) * GEM_Q1_DESCS)
>  
> +/* This structure is only used for MACB on SiFive FU540 devices */
> +struct sifive_fu540_macb_mgmt {
> +	void __iomem *reg;
> +	unsigned long rate;
> +	struct clk clk;
> +};
> +
> +struct macb_config {
> +	int (*txclk_init)(struct device_d *dev, struct clk **tx_clk);
> +};
> +
>  struct macb_device {
>  	void			__iomem *regs;
>  
> @@ -666,12 +677,108 @@ static void macb_init_rx_buffer_size(struct macb_device *bp, size_t size)
>  		   size, bp->rx_buffer_size);
>  }
>  
> +#ifdef CONFIG_COMMON_CLK
> +static struct sifive_fu540_macb_mgmt *mgmt;
> +
> +static unsigned long fu540_macb_tx_recalc_rate(struct clk *clk,
> +					       unsigned long parent_rate)
> +{
> +	return mgmt->rate;
> +}
> +
> +static long fu540_macb_tx_round_rate(struct clk *clk, unsigned long rate,
> +				     unsigned long *parent_rate)
> +{
> +	if (WARN_ON(rate < 2500000))
> +		return 2500000;
> +	else if (rate == 2500000)
> +		return 2500000;
> +	else if (WARN_ON(rate < 13750000))
> +		return 2500000;
> +	else if (WARN_ON(rate < 25000000))
> +		return 25000000;
> +	else if (rate == 25000000)
> +		return 25000000;
> +	else if (WARN_ON(rate < 75000000))
> +		return 25000000;
> +	else if (WARN_ON(rate < 125000000))
> +		return 125000000;
> +	else if (rate == 125000000)
> +		return 125000000;
> +
> +	WARN_ON(rate > 125000000);
> +
> +	return 125000000;
> +}
> +
> +static int fu540_macb_tx_set_rate(struct clk *clk, unsigned long rate,
> +				  unsigned long parent_rate)
> +{
> +	rate = fu540_macb_tx_round_rate(clk, rate, &parent_rate);
> +	if (rate != 125000000)
> +		iowrite32(1, mgmt->reg);
> +	else
> +		iowrite32(0, mgmt->reg);
> +	mgmt->rate = rate;
> +
> +	return 0;
> +}
> +
> +static const struct clk_ops fu540_c000_ops = {
> +	.recalc_rate = fu540_macb_tx_recalc_rate,
> +	.round_rate = fu540_macb_tx_round_rate,
> +	.set_rate = fu540_macb_tx_set_rate,
> +};
> +
> +static int fu540_c000_txclk_init(struct device_d *dev, struct clk **tx_clk)
> +{
> +	struct clk *clk;
> +	struct resource *res;
> +	int err = 0;
> +
> +	mgmt = xzalloc(sizeof(*mgmt));
> +
> +	res = dev_request_mem_resource(dev, 1);
> +	if (IS_ERR(res))
> +		return PTR_ERR(res);
> +
> +	mgmt->reg = IOMEM(res->start);
> +
> +	clk = &mgmt->clk;
> +
> +	clk->name = "sifive-gemgxl-mgmt";
> +	clk->ops = &fu540_c000_ops;
> +
> +	err = clk_register(&mgmt->clk);
> +	if (err)
> +		return err;
> +
> +	*tx_clk = &mgmt->clk;
> +
> +	err = clk_enable(*tx_clk);
> +	if (err) {
> +		dev_err(dev, "failed to enable tx_clk (%u)\n", err);
> +		*tx_clk = NULL;
> +		return err;
> +	}
> +
> +	dev_info(dev, "Registered clk switch '%s'\n", clk->name);
> +	return 0;
> +}
> +#else
> +static int fu540_c000_txclk_init(struct device_d *dev, struct clk **tx_clk)
> +{
> +	return -ENOSYS;
> +}
> +#endif
> +
>  static int macb_probe(struct device_d *dev)
>  {
>  	struct resource *iores;
>  	struct eth_device *edev;
>  	struct macb_device *macb;
>  	const char *pclk_name, *hclk_name;
> +	const struct macb_config *config = NULL;
>  	u32 ncfgr;
>  
>  	macb = xzalloc(sizeof(*macb));
> @@ -725,6 +832,8 @@ static int macb_probe(struct device_d *dev)
>  		macb->phy_addr = -1;
>  		pclk_name = "pclk";
>  		hclk_name = "hclk";
> +
> +		config = device_get_match_data(dev);
>  	} else {
>  		dev_err(dev, "macb: no platform_data\n");
>  		return -ENODEV;
> @@ -767,6 +876,12 @@ static int macb_probe(struct device_d *dev)
>  	if (!IS_ERR(macb->rxclk))
>  		clk_enable(macb->rxclk);
>  
> +	if (config) {
> +		int ret = config->txclk_init(dev, &macb->txclk);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	macb->is_gem = read_is_gem(macb);
>  
>  	if (macb_is_gem(macb))
> @@ -808,12 +923,17 @@ static void macb_remove(struct device_d *dev)
>  	macb_halt(&macb->netdev);
>  }
>  
> +static const struct macb_config fu540_c000_config = {
> +	.txclk_init = fu540_c000_txclk_init,
> +};
> +
>  static const struct of_device_id macb_dt_ids[] = {
>  	{ .compatible = "cdns,at91sam9260-macb",},
>  	{ .compatible = "atmel,sama5d2-gem",},
>  	{ .compatible = "atmel,sama5d3-gem",},
>  	{ .compatible = "cdns,zynq-gem",},
>  	{ .compatible = "cdns,zynqmp-gem",},
> +	{ .compatible = "sifive,fu540-c000-gem", .data = &fu540_c000_config },
>  	{ /* sentinel */ }
>  };
>  
> -- 
> 2.29.2
> 
> 
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