On Fri, 2017-10-13 at 12:16 +0800, Joel Stanley wrote: > According to the ASPEED datasheet, gigabit speeds require a clock of > 100MHz or higher. Other speeds require 25MHz or higher. This patch > configures a 100MHz clock if the system has a direct-attached > PHY, or 25MHz if the system is running NC-SI which is limited to 100MHz. > > There appear to be no other upstream users of the FTGMAC100 driver it is > hard to know the clocking requirements of other platforms. Therefore a > conservative approach was taken with enabling clocks. If the platform is > not ASPEED, both requesting the clock and configuring the speed is > skipped. > > Signed-off-by: Joel Stanley <j...@jms.id.au>
Tested on an AST2500 EVB and an OpenPOWER Palmetto (AST2400) machine.
Confirmed clock rates were nominally what was requested, and successfully
downloaded a 100MB test file.
Tested-by: Andrew Jeffery <and...@aj.id.au>
> ---
> Andrew, can you please give this one a spin on hardware?
>
> v3:
> - Fix errors from v2
> v2:
> - only touch the clocks on Aspeed platforms
> - unconditionally call clk_unprepare_disable
>
> drivers/net/ethernet/faraday/ftgmac100.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/net/ethernet/faraday/ftgmac100.c
> b/drivers/net/ethernet/faraday/ftgmac100.c
> index 9ed8e4b81530..78db8e62a83f 100644
> --- a/drivers/net/ethernet/faraday/ftgmac100.c
> +++ b/drivers/net/ethernet/faraday/ftgmac100.c
> @@ -21,6 +21,7 @@
>
> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>
> +#include <linux/clk.h>
> #include <linux/dma-mapping.h>
> #include <linux/etherdevice.h>
> #include <linux/ethtool.h>
> @@ -59,6 +60,9 @@
> /* Min number of tx ring entries before stopping queue */
> #define TX_THRESHOLD (MAX_SKB_FRAGS + 1)
>
> +#define FTGMAC_100MHZ 100000000
> +#define FTGMAC_25MHZ 25000000
> +
> struct ftgmac100 {
> /* Registers */
> struct resource *res;
> @@ -96,6 +100,7 @@ struct ftgmac100 {
> struct napi_struct napi;
> struct work_struct reset_task;
> struct mii_bus *mii_bus;
> + struct clk *clk;
>
> /* Link management */
> int cur_speed;
> @@ -1734,6 +1739,22 @@ static void ftgmac100_ncsi_handler(struct ncsi_dev *nd)
> nd->link_up ? "up" : "down");
> }
>
> +static void ftgmac100_setup_clk(struct ftgmac100 *priv)
> +{
> + priv->clk = devm_clk_get(priv->dev, NULL);
> + if (IS_ERR(priv->clk))
> + return;
> +
> + clk_prepare_enable(priv->clk);
> +
> + /* Aspeed specifies a 100MHz clock is required for up to
> + * 1000Mbit link speeds. As NCSI is limited to 100Mbit, 25MHz
> + * is sufficient
> + */
> + clk_set_rate(priv->clk, priv->use_ncsi ? FTGMAC_25MHZ :
> + FTGMAC_100MHZ);
> +}
> +
> static int ftgmac100_probe(struct platform_device *pdev)
> {
> struct resource *res;
> @@ -1830,6 +1851,9 @@ static int ftgmac100_probe(struct platform_device *pdev)
> goto err_setup_mdio;
> }
>
> + if (priv->is_aspeed)
> + ftgmac100_setup_clk(priv);
> +
> /* Default ring sizes */
> priv->rx_q_entries = priv->new_rx_q_entries = DEF_RX_QUEUE_ENTRIES;
> priv->tx_q_entries = priv->new_tx_q_entries = DEF_TX_QUEUE_ENTRIES;
> @@ -1883,6 +1907,8 @@ static int ftgmac100_remove(struct platform_device
> *pdev)
>
> unregister_netdev(netdev);
>
> + clk_disable_unprepare(priv->clk);
> +
> /* There's a small chance the reset task will have been re-queued,
> * during stop, make sure it's gone before we free the structure.
> */
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