ARC: [plat-hsdk] initial port for HSDK board

This initial port adds support of ARC HS Development Kit board with some
basic features such serial port, USB, SD/MMC and Ethernet.

Essentially we run Linux kernel on all 4 cores (i.e. utilize SMP) and
heavily use IO Coherency for speeding-up DMA-aware peripherals.

Note as opposed to other ARC boards we link Linux kernel to
0x9000_0000 intentionally because cores 1 and 3 configured with DCCM
situated at our more usual link base 0x8000_0000. We still can use
memory region starting at 0x8000_0000 as we reallocate DCCM in our
platform code.

Note that PAE remapping for DMA clients does not work due to an RTL bug,
so CREG_PAE register must be programmed to all zeroes, otherwise it will
cause problems with DMA to/from peripherals even if PAE40 is not used.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

1 files changed, 66 insertions, 0 deletions

diff --git a/arch/arc/plat-hsdk/platform.c b/arch/arc/plat-hsdk/platform.c
new file mode 100644
index 000000000000..a2e7fd17e36d
--- /dev/null
+++ b/arch/arc/plat-hsdk/platform.c
@@ -0,0 +1,66 @@
+/*
+ * ARC HSDK Platform support code
+ *
+ * Copyright (C) 2017 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <asm/arcregs.h>
+#include <asm/io.h>
+#include <asm/mach_desc.h>
+
+#define ARC_CCM_UNUSED_ADDR	0x60000000
+
+static void __init hsdk_init_per_cpu(unsigned int cpu)
+{
+	/*
+	 * By default ICCM is mapped to 0x7z while this area is used for
+	 * kernel virtual mappings, so move it to currently unused area.
+	 */
+	if (cpuinfo_arc700[cpu].iccm.sz)
+		write_aux_reg(ARC_REG_AUX_ICCM, ARC_CCM_UNUSED_ADDR);
+
+	/*
+	 * By default DCCM is mapped to 0x8z while this area is used by kernel,
+	 * so move it to currently unused area.
+	 */
+	if (cpuinfo_arc700[cpu].dccm.sz)
+		write_aux_reg(ARC_REG_AUX_DCCM, ARC_CCM_UNUSED_ADDR);
+}
+
+#define ARC_PERIPHERAL_BASE	0xf0000000
+#define CREG_BASE		(ARC_PERIPHERAL_BASE + 0x1000)
+#define CREG_PAE		(CREG_BASE + 0x180)
+#define CREG_PAE_UPDATE		(CREG_BASE + 0x194)
+
+static void __init hsdk_init_early(void)
+{
+	/*
+	 * PAE remapping for DMA clients does not work due to an RTL bug, so
+	 * CREG_PAE register must be programmed to all zeroes, otherwise it
+	 * will cause problems with DMA to/from peripherals even if PAE40 is
+	 * not used.
+	 */
+
+	/* Default is 1, which means "PAE offset = 4GByte" */
+	writel_relaxed(0, (void __iomem *) CREG_PAE);
+
+	/* Really apply settings made above */
+	writel(1, (void __iomem *) CREG_PAE_UPDATE);
+}
+
+static const char *hsdk_compat[] __initconst = {
+	"snps,hsdk",
+	NULL,
+};
+
+MACHINE_START(SIMULATION, "hsdk")
+	.dt_compat	= hsdk_compat,
+	.init_early     = hsdk_init_early,
+	.init_per_cpu	= hsdk_init_per_cpu,
+MACHINE_END