Commit 8bfff048 authored by Russell King (Oracle)'s avatar Russell King (Oracle) Committed by Jakub Kicinski
Browse files

net: stmmac: thead: ensure divisor gives proper rate 



thead was checking that the stmmac_clk rate was a multiple of the
RGMII rates for 1G and 100M, but didn't check for 10M. Rather than
use this with hard-coded speeds, check that the calculated divisor
gives the required rate by multplying the transmit clock rate back
up to the stmmac clock rate and checking that it agrees.

Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Tested-by: default avatarDrew Fustini <drew@pdp7.com>
Link: https://patch.msgid.link/E1tlToD-004W3g-HB@rmk-PC.armlinux.org.uk


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 171fd7cb

drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c

+4 −8
Original line number Diff line number Diff line
@@ -45,9 +45,6 @@ 
#define  TXCLK_DIR_OUTPUT		FIELD_PREP(TXCLK_DIR_MASK, 0)

#define  TXCLK_DIR_INPUT		FIELD_PREP(TXCLK_DIR_MASK, 1)



#define GMAC_GMII_RGMII_RATE	125000000

#define GMAC_MII_RATE		25000000



struct thead_dwmac {

	struct plat_stmmacenet_data *plat;

	void __iomem *apb_base;
@@ -124,11 +121,6 @@ static void thead_dwmac_fix_speed(void *priv, int speed, unsigned int mode) 
	case PHY_INTERFACE_MODE_RGMII_RXID:

	case PHY_INTERFACE_MODE_RGMII_TXID:

		rate = clk_get_rate(plat->stmmac_clk);

		if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||

		    rate % GMAC_MII_RATE != 0) {

			dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);

			return;

		}



		writel(0, dwmac->apb_base + GMAC_PLLCLK_DIV);
@@ -139,6 +131,10 @@ static void thead_dwmac_fix_speed(void *priv, int speed, unsigned int mode) 
		}



		div = rate / tx_rate;

		if (rate != tx_rate * div) {

			dev_err(dwmac->dev, "invalid gmac rate %lu\n", rate);

			return;

		}



		reg = FIELD_PREP(GMAC_PLLCLK_DIV_EN, 1) |

		      FIELD_PREP(GMAC_PLLCLK_DIV_NUM, div);