drivers: net: cpsw: add am335x errata workarround for interrutps

As per Am335x Errata [1] Advisory 1.0.9, The CPSW C0_TX_PEND and
C0_RX_PEND interrupt outputs provide a single transmit interrupt
that combines transmit channel interrupts TXPEND[7:0] and a
single receive interrupt that combines receive channel interrupts
RXPEND[7:0]. The TXPEND[0] and RXPEND[0] interrupt outputs are
connected to the ARM Cortex-A8 interrupt controller (INTC) rather
than the C0_TX_PEND and C0_RX_PEND interrupt outputs. So even
though CPSW interrupt is cleared by writing appropriate values to
EOI register the interrupt is not cleared in IRQ controller. So
interrupt is still pending and CPU is struck in ISR, the
workaround is to disable the interrupts in ARM irq controller.

[1] http://www.ti.com/lit/er/sprz360f/sprz360f.pdf

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/cpsw.c

@@ -387,6 +387,9 @@ struct cpsw_priv {
 	struct cpsw_ale			*ale;
 	bool				rx_pause;
 	bool				tx_pause;
+	bool				quirk_irq;
+	bool				rx_irq_disabled;
+	bool				tx_irq_disabled;
 	/* snapshot of IRQ numbers */
 	u32 irqs_table[4];
 	u32 num_irqs;
@@ -755,6 +758,11 @@ static irqreturn_t cpsw_tx_interrupt(int irq, void *dev_id)
 	writel(0, &priv->wr_regs->tx_en);
 	cpdma_ctlr_eoi(priv->dma, CPDMA_EOI_TX);
 
+	if (priv->quirk_irq) {
+		disable_irq_nosync(priv->irqs_table[1]);
+		priv->tx_irq_disabled = true;
+	}
+
 	napi_schedule(&priv->napi_tx);
 	return IRQ_HANDLED;
 }
@@ -766,6 +774,11 @@ static irqreturn_t cpsw_rx_interrupt(int irq, void *dev_id)
 	cpdma_ctlr_eoi(priv->dma, CPDMA_EOI_RX);
 	writel(0, &priv->wr_regs->rx_en);
 
+	if (priv->quirk_irq) {
+		disable_irq_nosync(priv->irqs_table[0]);
+		priv->rx_irq_disabled = true;
+	}
+
 	napi_schedule(&priv->napi_rx);
 	return IRQ_HANDLED;
 }
@@ -779,6 +792,10 @@ static int cpsw_tx_poll(struct napi_struct *napi_tx, int budget)
 	if (num_tx < budget) {
 		napi_complete(napi_tx);
 		writel(0xff, &priv->wr_regs->tx_en);
+		if (priv->quirk_irq && priv->tx_irq_disabled) {
+			priv->tx_irq_disabled = false;
+			enable_irq(priv->irqs_table[1]);
+		}
 	}
 
 	if (num_tx)
@@ -796,6 +813,10 @@ static int cpsw_rx_poll(struct napi_struct *napi_rx, int budget)
 	if (num_rx < budget) {
 		napi_complete(napi_rx);
 		writel(0xff, &priv->wr_regs->rx_en);
+		if (priv->quirk_irq && priv->rx_irq_disabled) {
+			priv->rx_irq_disabled = false;
+			enable_irq(priv->irqs_table[0]);
+		}
 	}
 
 	if (num_rx)
@@ -1267,6 +1288,16 @@ static int cpsw_ndo_open(struct net_device *ndev)
 		napi_enable(&priv_sl0->napi_rx);
 		napi_enable(&priv_sl0->napi_tx);
 
+		if (priv_sl0->tx_irq_disabled) {
+			priv_sl0->tx_irq_disabled = false;
+			enable_irq(priv->irqs_table[1]);
+		}
+
+		if (priv_sl0->rx_irq_disabled) {
+			priv_sl0->rx_irq_disabled = false;
+			enable_irq(priv->irqs_table[0]);
+		}
+
 		if (WARN_ON(!priv->data.rx_descs))
 			priv->data.rx_descs = 128;
 
@@ -2128,6 +2159,44 @@ static int cpsw_probe_dual_emac(struct platform_device *pdev,
 	return ret;
 }
 
+#define CPSW_QUIRK_IRQ		BIT(0)
+
+static struct platform_device_id cpsw_devtype[] = {
+	{
+		/* keep it for existing comaptibles */
+		.name = "cpsw",
+		.driver_data = CPSW_QUIRK_IRQ,
+	}, {
+		.name = "am335x-cpsw",
+		.driver_data = CPSW_QUIRK_IRQ,
+	}, {
+		.name = "am4372-cpsw",
+		.driver_data = 0,
+	}, {
+		.name = "dra7-cpsw",
+		.driver_data = 0,
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(platform, cpsw_devtype);
+
+enum ti_cpsw_type {
+	CPSW = 0,
+	AM335X_CPSW,
+	AM4372_CPSW,
+	DRA7_CPSW,
+};
+
+static const struct of_device_id cpsw_of_mtable[] = {
+	{ .compatible = "ti,cpsw", .data = &cpsw_devtype[CPSW], },
+	{ .compatible = "ti,am335x-cpsw", .data = &cpsw_devtype[AM335X_CPSW], },
+	{ .compatible = "ti,am4372-cpsw", .data = &cpsw_devtype[AM4372_CPSW], },
+	{ .compatible = "ti,dra7-cpsw", .data = &cpsw_devtype[DRA7_CPSW], },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, cpsw_of_mtable);
+
 static int cpsw_probe(struct platform_device *pdev)
 {
 	struct cpsw_platform_data	*data;
@@ -2137,6 +2206,7 @@ static int cpsw_probe(struct platform_device *pdev)
 	struct cpsw_ale_params		ale_params;
 	void __iomem			*ss_regs;
 	struct resource			*res, *ss_res;
+	const struct of_device_id	*of_id;
 	u32 slave_offset, sliver_offset, slave_size;
 	int ret = 0, i;
 	int irq;
@@ -2327,6 +2397,13 @@ static int cpsw_probe(struct platform_device *pdev)
 		goto clean_ale_ret;
 	}
 
+	of_id = of_match_device(cpsw_of_mtable, &pdev->dev);
+	if (of_id) {
+		pdev->id_entry = of_id->data;
+		if (pdev->id_entry->driver_data)
+			priv->quirk_irq = true;
+	}
+
 	/* Grab RX and TX IRQs. Note that we also have RX_THRESHOLD and
 	 * MISC IRQs which are always kept disabled with this driver so
 	 * we will not request them.
@@ -2491,12 +2568,6 @@ static int cpsw_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(cpsw_pm_ops, cpsw_suspend, cpsw_resume);
 
-static const struct of_device_id cpsw_of_mtable[] = {
-	{ .compatible = "ti,cpsw", },
-	{ /* sentinel */ },
-};
-MODULE_DEVICE_TABLE(of, cpsw_of_mtable);
-
 static struct platform_driver cpsw_driver = {
 	.driver = {
 		.name	 = "cpsw",