ARCv3: Add CDMA support driver

Driver to support Cluster DMA(CDMA) controller for ARCv3.
For HS58 tested on nSIM and HAPS using 'dmatest' driver.
For HS68 tested on nSIM using 'dmatest' driver.

Known limitations:
Don't specify 'test_buf_size' 'dmatest' parameter more then 750000 when
L2$ is enabled. Looks like L2$ operations in cache-arcv3.c:scm_op_rgn()
fails when sz > 750000. Probably it is restriction in HW. Otherwise
the kernel will crash.

Author: xxkent

arch/arc/boot/dts/skeleton_haps_idu.dtsi

@@ -68,5 +68,12 @@
 			#interrupt-cells = <1>;
 			interrupts = <23>;
 		};
+
+		cdma: custer_dma {
+			compatible = "snps,cluster-dma";
+			#interrupt-cells = <1>;
+			interrupts = <21>;
+			cdma-max-desc-len = <131071>;
+		};
 	};
 };

arch/arc/kernel/intc-arcv2.c

@@ -193,7 +193,9 @@ init_onchip_IRQ(struct device_node *intc, struct device_node *parent)
 #ifdef CONFIG_SMP
 	irq_create_mapping(root_domain, IPI_IRQ);
 #endif
+#ifndef CONFIG_ISA_ARCV3
 	irq_create_mapping(root_domain, SOFTIRQ_IRQ);
+#endif
 
 	return 0;
 }

arch/arc/kernel/mcip.c

@@ -83,7 +83,9 @@ static void mcip_setup_per_cpu(int cpu)
 	READ_BCR(ARC_REG_MCIP_BCR, mp);
 
 	smp_ipi_irq_setup(cpu, IPI_IRQ);
+#ifndef CONFIG_ISA_ARCV3
 	smp_ipi_irq_setup(cpu, SOFTIRQ_IRQ);
+#endif
 
 	/* Update GFRC halt mask as new CPU came online */
 	if (mp.gfrc)
@@ -101,7 +103,9 @@ static void mcip_ipi_send(int cpu)
 
 	/* ARConnect can only send IPI to others */
 	if (unlikely(cpu == raw_smp_processor_id())) {
+#ifndef CONFIG_ISA_ARCV3
 		arc_softirq_trigger(SOFTIRQ_IRQ);
+#endif
 		return;
 	}
 
@@ -127,7 +131,9 @@ static void mcip_ipi_clear(int irq)
 	unsigned long flags;
 
 	if (unlikely(irq == SOFTIRQ_IRQ)) {
+#ifndef CONFIG_ISA_ARCV3
 		arc_softirq_clear(irq);
+#endif
 		return;
 	}
 

arch/arc/mm/init.c

@@ -102,7 +102,7 @@ void __init setup_arch_memory(void)
 	setup_initial_init_mm(_text, _etext, _edata, _end);
 
 	/* first page of system - kernel .vector starts here */
-	min_low_pfn = virt_to_pfn(CONFIG_LINUX_RAM_BASE);
+	min_low_pfn = virt_to_pfn(__va(CONFIG_LINUX_RAM_BASE));
 
 	/* Last usable page of low mem */
 	max_low_pfn = max_pfn = PFN_DOWN(low_mem_start + low_mem_sz);

drivers/dma/Kconfig

@@ -181,6 +181,15 @@ config DW_AXI_DMAC
 	  NOTE: This driver wasn't tested on 64 bit platform because
 	  of lack 64 bit platform with Synopsys DW AXI DMAC.
 
+config DW_CDMA
+	tristate "Synopsys DesignWare ARC HS Hammerhead Cluster DMA driver"
+	depends on OF || COMPILE_TEST
+	depends on HAS_IOMEM
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Enable support for Synopsys DesignWare Cluster DMA.
+
 config EP93XX_DMA
 	bool "Cirrus Logic EP93xx DMA support"
 	depends on ARCH_EP93XX || COMPILE_TEST

drivers/dma/Makefile

@@ -27,6 +27,7 @@ obj-$(CONFIG_DMA_SA11X0) += sa11x0-dma.o
 obj-$(CONFIG_DMA_SUN4I) += sun4i-dma.o
 obj-$(CONFIG_DMA_SUN6I) += sun6i-dma.o
 obj-$(CONFIG_DW_AXI_DMAC) += dw-axi-dmac/
+obj-$(CONFIG_DW_CDMA) += dw-cdma/
 obj-$(CONFIG_DW_DMAC_CORE) += dw/
 obj-$(CONFIG_DW_EDMA) += dw-edma/
 obj-$(CONFIG_EP93XX_DMA) += ep93xx_dma.o

drivers/dma/dw-cdma/Makefile

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_DW_CDMA) += dw-cdma-platform.o