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[PATCH v2 net-next 1/3] net: ethernet: cadence-macb: Add disabled usrio caps

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On some platforms, the macb integration does not use the USRIO
register to configure the (R)MII port and clocks.
When the register is not implemented and the MACB error signal
is connected to the bus error, reading or writing to the USRIO
register can trigger some Imprecise External Aborts on ARM platforms.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/net/ethernet/cadence/macb.c | 27 +++++++++++++++------------
 drivers/net/ethernet/cadence/macb.h |  1 +
 2 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index 169059c..9325140 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -2122,7 +2122,8 @@ static void macb_get_regs(struct net_device *dev, struct ethtool_regs *regs,
 	regs_buff[10] = macb_tx_dma(&bp->queues[0], tail);
 	regs_buff[11] = macb_tx_dma(&bp->queues[0], head);
 
-	regs_buff[12] = macb_or_gem_readl(bp, USRIO);
+	if (!(bp->caps & MACB_CAPS_USRIO_DISABLED))
+		regs_buff[12] = macb_or_gem_readl(bp, USRIO);
 	if (macb_is_gem(bp)) {
 		regs_buff[13] = gem_readl(bp, DMACFG);
 	}
@@ -2401,19 +2402,21 @@ static int macb_init(struct platform_device *pdev)
 		dev->hw_features &= ~NETIF_F_SG;
 	dev->features = dev->hw_features;
 
-	val = 0;
-	if (bp->phy_interface == PHY_INTERFACE_MODE_RGMII)
-		val = GEM_BIT(RGMII);
-	else if (bp->phy_interface == PHY_INTERFACE_MODE_RMII &&
-		 (bp->caps & MACB_CAPS_USRIO_DEFAULT_IS_MII))
-		val = MACB_BIT(RMII);
-	else if (!(bp->caps & MACB_CAPS_USRIO_DEFAULT_IS_MII))
-		val = MACB_BIT(MII);
+	if (!(bp->caps & MACB_CAPS_USRIO_DISABLED)) {
+		val = 0;
+		if (bp->phy_interface == PHY_INTERFACE_MODE_RGMII)
+			val = GEM_BIT(RGMII);
+		else if (bp->phy_interface == PHY_INTERFACE_MODE_RMII &&
+			 (bp->caps & MACB_CAPS_USRIO_DEFAULT_IS_MII))
+			val = MACB_BIT(RMII);
+		else if (!(bp->caps & MACB_CAPS_USRIO_DEFAULT_IS_MII))
+			val = MACB_BIT(MII);
 
-	if (bp->caps & MACB_CAPS_USRIO_HAS_CLKEN)
-		val |= MACB_BIT(CLKEN);
+		if (bp->caps & MACB_CAPS_USRIO_HAS_CLKEN)
+			val |= MACB_BIT(CLKEN);
 
-	macb_or_gem_writel(bp, USRIO, val);
+		macb_or_gem_writel(bp, USRIO, val);
+	}
 
 	/* Set MII management clock divider */
 	val = macb_mdc_clk_div(bp);
diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index d83b0db..65ea049 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -400,6 +400,7 @@
 #define MACB_CAPS_USRIO_HAS_CLKEN		0x00000002
 #define MACB_CAPS_USRIO_DEFAULT_IS_MII		0x00000004
 #define MACB_CAPS_NO_GIGABIT_HALF		0x00000008
+#define MACB_CAPS_USRIO_DISABLED		0x00000010
 #define MACB_CAPS_FIFO_MODE			0x10000000
 #define MACB_CAPS_GIGABIT_MODE_AVAILABLE	0x20000000
 #define MACB_CAPS_SG_DISABLED			0x40000000
-- 
1.9.1

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Thread

[PATCH net 0/2] Add a property to disable MACB USRIO register Neil Armstrong <narmstrong@baylibre.com> - 2015-12-07 12:00 +0100
  [PATCH net 1/2] net: cadence: macb: Disable USRIO register on some platforms Neil Armstrong <narmstrong@baylibre.com> - 2015-12-07 12:10 +0100
    Re: [PATCH net 1/2] net: cadence: macb: Disable USRIO register on  some platforms David Miller <davem@davemloft.net> - 2015-12-07 20:10 +0100
    Re: [PATCH net 1/2] net: cadence: macb: Disable USRIO register on  some platforms Josh Cartwright <joshc@ni.com> - 2015-12-07 20:40 +0100
      Re: [PATCH net 1/2] net: cadence: macb: Disable USRIO register on  some platforms Neil Armstrong <narmstrong@baylibre.com> - 2015-12-08 10:30 +0100
        Re: [PATCH net 1/2] net: cadence: macb: Disable USRIO register on  some platforms Nicolas Ferre <nicolas.ferre@atmel.com> - 2015-12-08 10:40 +0100
  [PATCH v2 net-next 3/3] bindings: ethernet: macb: Add optional caps properties Neil Armstrong <narmstrong@baylibre.com> - 2015-12-08 15:00 +0100
    Re: [PATCH v2 net-next 3/3] bindings: ethernet: macb: Add optional  caps properties Rob Herring <robh@kernel.org> - 2015-12-09 05:00 +0100
  [PATCH v2 net-next 2/3] net: ethernet: cadence-macb: Add fallback to read DT provided caps Neil Armstrong <narmstrong@baylibre.com> - 2015-12-08 15:00 +0100
    Re: [PATCH v2 net-next 2/3] net: ethernet: cadence-macb: Add fallback to read DT provided caps Arnd Bergmann <arnd@arndb.de> - 2015-12-08 16:10 +0100
      Re: [PATCH v2 net-next 2/3] net: ethernet: cadence-macb: Add fallback  to read DT provided caps Nicolas Ferre <nicolas.ferre@atmel.com> - 2015-12-08 17:30 +0100
  [PATCH v2 net-next 1/3] net: ethernet: cadence-macb: Add disabled usrio caps Neil Armstrong <narmstrong@baylibre.com> - 2015-12-08 15:00 +0100
  [PATCH v2 net-next 0/3] Add new capability and parse from DT Neil Armstrong <narmstrong@baylibre.com> - 2015-12-08 15:00 +0100

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