MSCC: add support for Ocelot SoCs

This family of SoCs are found in the Microsemi Switches solution and have
already a support in the linux kernel.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

1 files changed, 90 insertions, 0 deletions

diff --git a/arch/mips/mach-mscc/cpu.c b/arch/mips/mach-mscc/cpu.c
new file mode 100644
index 0000000000..b503e1407b
--- /dev/null
+++ b/arch/mips/mach-mscc/cpu.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (c) 2018 Microsemi Corporation
+ */
+
+#include <common.h>
+
+#include <asm/io.h>
+#include <asm/types.h>
+
+#include <mach/tlb.h>
+#include <mach/ddr.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#if CONFIG_SYS_SDRAM_SIZE <= SZ_64M
+#define MSCC_RAM_TLB_SIZE   SZ_64M
+#define MSCC_ATTRIB2   MMU_REGIO_INVAL
+#elif CONFIG_SYS_SDRAM_SIZE <= SZ_128M
+#define MSCC_RAM_TLB_SIZE   SZ_64M
+#define MSCC_ATTRIB2   MMU_REGIO_RW
+#elif CONFIG_SYS_SDRAM_SIZE <= SZ_256M
+#define MSCC_RAM_TLB_SIZE   SZ_256M
+#define MSCC_ATTRIB2   MMU_REGIO_INVAL
+#elif CONFIG_SYS_SDRAM_SIZE <= SZ_512M
+#define MSCC_RAM_TLB_SIZE   SZ_256M
+#define MSCC_ATTRIB2   MMU_REGIO_RW
+#else
+#define MSCC_RAM_TLB_SIZE   SZ_512M
+#define MSCC_ATTRIB2   MMU_REGIO_RW
+#endif
+
+/* NOTE: lowlevel_init() function does not have access to the
+ * stack. Thus, all called functions must be inlined, and (any) local
+ * variables must be kept in registers.
+ */
+void vcoreiii_tlb_init(void)
+{
+	register int tlbix = 0;
+
+	/*
+	 * Unlike most of the MIPS based SoCs, the IO register address
+	 * are not in KSEG0. The mainline linux kernel built in legacy
+	 * mode needs to access some of the registers very early in
+	 * the boot and make the assumption that the bootloader has
+	 * already configured them, so we have to match this
+	 * expectation.
+	 */
+	create_tlb(tlbix++, MSCC_IO_ORIGIN1_OFFSET, SZ_16M, MMU_REGIO_RW,
+		   MMU_REGIO_RW);
+
+#if  CONFIG_SYS_TEXT_BASE == MSCC_FLASH_TO
+	/*
+	 * If U-Boot is located in NOR then we want to be able to use
+	 * the data cache in order to boot in a decent duration
+	 */
+	create_tlb(tlbix++, MSCC_FLASH_TO, SZ_16M, MMU_REGIO_RO_C,
+		   MMU_REGIO_RO_C);
+	create_tlb(tlbix++, MSCC_FLASH_TO + SZ_32M, SZ_16M, MMU_REGIO_RO_C,
+		   MMU_REGIO_RO_C);
+
+	/*
+	 * Using cache for RAM also helps to improve boot time. Thanks
+	 * to this the time to relocate U-Boot in RAM went from 2.092
+	 * secs to 0.104 secs.
+	 */
+	create_tlb(tlbix++, MSCC_DDR_TO, MSCC_RAM_TLB_SIZE, MMU_REGIO_RW,
+		   MSCC_ATTRIB2);
+
+	/* Enable caches by clearing the bit ERL, which is set on reset */
+	write_c0_status(read_c0_status() & ~BIT(2));
+#endif /* CONFIG_SYS_TEXT_BASE */
+}
+
+int mach_cpu_init(void)
+{
+	/* Speed up NOR flash access */
+	writel(ICPU_SPI_MST_CFG_CS_DESELECT_TIME(0x19) +
+	       ICPU_SPI_MST_CFG_CLK_DIV(9), BASE_CFG + ICPU_SPI_MST_CFG);
+	/*
+	 * Legacy and mainline linux kernel expect that the
+	 * interruption map was set as it was done by redboot.
+	 */
+	writel(~0, BASE_CFG + ICPU_DST_INTR_MAP(0));
+	writel(0, BASE_CFG + ICPU_DST_INTR_MAP(1));
+	writel(0, BASE_CFG + ICPU_DST_INTR_MAP(2));
+	writel(0, BASE_CFG + ICPU_DST_INTR_MAP(3));
+
+	return 0;
+}