MIPS: ath79: Improve the DDR controller interface

The DDR controller need to be used by the IRQ controller to flush
the write buffer of some devices before running the IRQ handler.
It is also used by the PCI controller to setup the PCI memory windows.

The current interface used to access the DDR controller doesn't
provides any useful abstraction and simply rely on a shared global
pointer.

Replace this by a simple API to setup the PCI memory windows and use
the write buffer flush independently of the SoC type. That remove the
need for the shared global pointer, simplify the IRQ handler code.

[ralf@linux-mips.org: Folded in Alban Bedel's follup fix.]

Signed-off-by: Alban Bedel <albeu@free.fr>
Cc: linux-mips@linux-mips.org
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Gabor Juhos <juhosg@openwrt.org>
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/9773/
Patchwork: http://patchwork.linux-mips.org/patch/10543/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 28 insertions, 109 deletions

diff --git a/arch/mips/ath79/irq.c b/arch/mips/ath79/irq.c
index 6adae36..2c3991a 100644
--- a/arch/mips/ath79/irq.c
+++ b/arch/mips/ath79/irq.c
@@ -24,9 +24,6 @@
 #include <asm/mach-ath79/ar71xx_regs.h>
 #include "common.h"
 
-static void (*ath79_ip2_handler)(void);
-static void (*ath79_ip3_handler)(void);
-
 static void ath79_misc_irq_handler(unsigned int irq, struct irq_desc *desc)
 {
 	void __iomem *base = ath79_reset_base;
@@ -129,10 +126,10 @@ static void ar934x_ip2_irq_dispatch(unsigned int irq, struct irq_desc *desc)
 	status = ath79_reset_rr(AR934X_RESET_REG_PCIE_WMAC_INT_STATUS);
 
 	if (status & AR934X_PCIE_WMAC_INT_PCIE_ALL) {
-		ath79_ddr_wb_flush(AR934X_DDR_REG_FLUSH_PCIE);
+		ath79_ddr_wb_flush(3);
 		generic_handle_irq(ATH79_IP2_IRQ(0));
 	} else if (status & AR934X_PCIE_WMAC_INT_WMAC_ALL) {
-		ath79_ddr_wb_flush(AR934X_DDR_REG_FLUSH_WMAC);
+		ath79_ddr_wb_flush(4);
 		generic_handle_irq(ATH79_IP2_IRQ(1));
 	} else {
 		spurious_interrupt();
@@ -235,128 +232,50 @@ static void qca955x_irq_init(void)
 	irq_set_chained_handler(ATH79_CPU_IRQ(3), qca955x_ip3_irq_dispatch);
 }
 
-asmlinkage void plat_irq_dispatch(void)
-{
-	unsigned long pending;
-
-	pending = read_c0_status() & read_c0_cause() & ST0_IM;
-
-	if (pending & STATUSF_IP7)
-		do_IRQ(ATH79_CPU_IRQ(7));
-
-	else if (pending & STATUSF_IP2)
-		ath79_ip2_handler();
-
-	else if (pending & STATUSF_IP4)
-		do_IRQ(ATH79_CPU_IRQ(4));
-
-	else if (pending & STATUSF_IP5)
-		do_IRQ(ATH79_CPU_IRQ(5));
-
-	else if (pending & STATUSF_IP3)
-		ath79_ip3_handler();
-
-	else if (pending & STATUSF_IP6)
-		do_IRQ(ATH79_CPU_IRQ(6));
-
-	else
-		spurious_interrupt();
-}
-
 /*
  * The IP2/IP3 lines are tied to a PCI/WMAC/USB device. Drivers for
  * these devices typically allocate coherent DMA memory, however the
  * DMA controller may still have some unsynchronized data in the FIFO.
  * Issue a flush in the handlers to ensure that the driver sees
  * the update.
+ *
+ * This array map the interrupt lines to the DDR write buffer channels.
  */
 
-static void ath79_default_ip2_handler(void)
-{
-	do_IRQ(ATH79_CPU_IRQ(2));
-}
-
-static void ath79_default_ip3_handler(void)
-{
-	do_IRQ(ATH79_CPU_IRQ(3));
-}
-
-static void ar71xx_ip2_handler(void)
-{
-	ath79_ddr_wb_flush(AR71XX_DDR_REG_FLUSH_PCI);
-	do_IRQ(ATH79_CPU_IRQ(2));
-}
-
-static void ar724x_ip2_handler(void)
-{
-	ath79_ddr_wb_flush(AR724X_DDR_REG_FLUSH_PCIE);
-	do_IRQ(ATH79_CPU_IRQ(2));
-}
-
-static void ar913x_ip2_handler(void)
-{
-	ath79_ddr_wb_flush(AR913X_DDR_REG_FLUSH_WMAC);
-	do_IRQ(ATH79_CPU_IRQ(2));
-}
-
-static void ar933x_ip2_handler(void)
-{
-	ath79_ddr_wb_flush(AR933X_DDR_REG_FLUSH_WMAC);
-	do_IRQ(ATH79_CPU_IRQ(2));
-}
-
-static void ar71xx_ip3_handler(void)
-{
-	ath79_ddr_wb_flush(AR71XX_DDR_REG_FLUSH_USB);
-	do_IRQ(ATH79_CPU_IRQ(3));
-}
+static unsigned irq_wb_chan[8] = {
+	-1, -1, -1, -1, -1, -1, -1, -1,
+};
 
-static void ar724x_ip3_handler(void)
+asmlinkage void plat_irq_dispatch(void)
 {
-	ath79_ddr_wb_flush(AR724X_DDR_REG_FLUSH_USB);
-	do_IRQ(ATH79_CPU_IRQ(3));
-}
+	unsigned long pending;
+	int irq;
 
-static void ar913x_ip3_handler(void)
-{
-	ath79_ddr_wb_flush(AR913X_DDR_REG_FLUSH_USB);
-	do_IRQ(ATH79_CPU_IRQ(3));
-}
+	pending = read_c0_status() & read_c0_cause() & ST0_IM;
 
-static void ar933x_ip3_handler(void)
-{
-	ath79_ddr_wb_flush(AR933X_DDR_REG_FLUSH_USB);
-	do_IRQ(ATH79_CPU_IRQ(3));
-}
+	if (!pending) {
+		spurious_interrupt();
+		return;
+	}
 
-static void ar934x_ip3_handler(void)
-{
-	ath79_ddr_wb_flush(AR934X_DDR_REG_FLUSH_USB);
-	do_IRQ(ATH79_CPU_IRQ(3));
+	pending >>= CAUSEB_IP;
+	while (pending) {
+		irq = fls(pending) - 1;
+		if (irq < ARRAY_SIZE(irq_wb_chan) && irq_wb_chan[irq] != -1)
+			ath79_ddr_wb_flush(irq_wb_chan[irq]);
+		do_IRQ(MIPS_CPU_IRQ_BASE + irq);
+		pending &= ~BIT(irq);
+	}
 }
 
 void __init arch_init_irq(void)
 {
-	if (soc_is_ar71xx()) {
-		ath79_ip2_handler = ar71xx_ip2_handler;
-		ath79_ip3_handler = ar71xx_ip3_handler;
-	} else if (soc_is_ar724x()) {
-		ath79_ip2_handler = ar724x_ip2_handler;
-		ath79_ip3_handler = ar724x_ip3_handler;
-	} else if (soc_is_ar913x()) {
-		ath79_ip2_handler = ar913x_ip2_handler;
-		ath79_ip3_handler = ar913x_ip3_handler;
-	} else if (soc_is_ar933x()) {
-		ath79_ip2_handler = ar933x_ip2_handler;
-		ath79_ip3_handler = ar933x_ip3_handler;
+	if (soc_is_ar71xx() || soc_is_ar724x() ||
+	    soc_is_ar913x() || soc_is_ar933x()) {
+		irq_wb_chan[2] = 3;
+		irq_wb_chan[3] = 2;
 	} else if (soc_is_ar934x()) {
-		ath79_ip2_handler = ath79_default_ip2_handler;
-		ath79_ip3_handler = ar934x_ip3_handler;
-	} else if (soc_is_qca955x()) {
-		ath79_ip2_handler = ath79_default_ip2_handler;
-		ath79_ip3_handler = ath79_default_ip3_handler;
-	} else {
-		BUG();
+		irq_wb_chan[3] = 2;
 	}
 
 	mips_cpu_irq_init();