arch/arc/plat-hsdk/platform.c

Source file repositories/reference/linux-study-clean/arch/arc/plat-hsdk/platform.c

File Facts

System
Linux kernel
Corpus path
arch/arc/plat-hsdk/platform.c
Extension
.c
Size
10709 bytes
Lines
327
Domain
Architecture Layer
Bucket
arch/arc
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 * ARC HSDK Platform support code
 *
 * Copyright (C) 2017 Synopsys, Inc. (www.synopsys.com)
 */

#include <linux/init.h>
#include <linux/of_fdt.h>
#include <linux/libfdt.h>
#include <linux/smp.h>
#include <asm/arcregs.h>
#include <asm/io.h>
#include <asm/mach_desc.h>

int arc_hsdk_axi_dmac_coherent __section(".data") = 0;

#define ARC_CCM_UNUSED_ADDR	0x60000000


#define ARC_PERIPHERAL_BASE	0xf0000000
#define CREG_BASE		(ARC_PERIPHERAL_BASE + 0x1000)

#define SDIO_BASE		(ARC_PERIPHERAL_BASE + 0xA000)
#define SDIO_UHS_REG_EXT	(SDIO_BASE + 0x108)
#define SDIO_UHS_REG_EXT_DIV_2	(2 << 30)

#define HSDK_GPIO_INTC          (ARC_PERIPHERAL_BASE + 0x3000)

static void __init hsdk_enable_gpio_intc_wire(void)
{
	/*
	 * Peripherals on CPU Card are wired to cpu intc via intermediate
	 * DW APB GPIO blocks (mainly for debouncing)
	 *
	 *         ---------------------
	 *        |  snps,archs-intc  |
	 *        ---------------------
	 *                  |
	 *        ----------------------
	 *        | snps,archs-idu-intc |
	 *        ----------------------
	 *         |   |     |   |    |
	 *         | [eth] [USB]    [... other peripherals]
	 *         |
	 * -------------------
	 * | snps,dw-apb-intc |
	 * -------------------
	 *  |      |   |   |
	 * [Bt] [HAPS]   [... other peripherals]
	 *
	 * Current implementation of "irq-dw-apb-ictl" driver doesn't work well
	 * with stacked INTCs. In particular problem happens if its master INTC
	 * not yet instantiated. See discussion here -
	 * https://lore.kernel.org/lkml/54F6FE2C.7020309@synopsys.com
	 *
	 * So setup the first gpio block as a passive pass thru and hide it from
	 * DT hardware topology - connect intc directly to cpu intc
	 * The GPIO "wire" needs to be init nevertheless (here)
	 *
	 * One side adv is that peripheral interrupt handling avoids one nested
	 * intc ISR hop
	 *
	 * According to HSDK User's Manual [1], "Table 2 Interrupt Mapping"
	 * we have the following GPIO input lines used as sources of interrupt:
	 * - GPIO[0] - Bluetooth interrupt of RS9113 module
	 * - GPIO[2] - HAPS interrupt (on HapsTrak 3 connector)
	 * - GPIO[3] - Audio codec (MAX9880A) interrupt
	 * - GPIO[8-23] - Available on Arduino and PMOD_x headers
	 * For now there's no use of Arduino and PMOD_x headers in Linux
	 * use-case so we only enable lines 0, 2 and 3.
	 *
	 * [1] https://github.com/foss-for-synopsys-dwc-arc-processors/ARC-Development-Systems-Forum/wiki/docs/ARC_HSDK_User_Guide.pdf
	 */
#define GPIO_INTEN              (HSDK_GPIO_INTC + 0x30)
#define GPIO_INTMASK            (HSDK_GPIO_INTC + 0x34)
#define GPIO_INTTYPE_LEVEL      (HSDK_GPIO_INTC + 0x38)
#define GPIO_INT_POLARITY       (HSDK_GPIO_INTC + 0x3c)
#define GPIO_INT_CONNECTED_MASK	0x0d

	iowrite32(0xffffffff, (void __iomem *) GPIO_INTMASK);
	iowrite32(~GPIO_INT_CONNECTED_MASK, (void __iomem *) GPIO_INTMASK);
	iowrite32(0x00000000, (void __iomem *) GPIO_INTTYPE_LEVEL);
	iowrite32(0xffffffff, (void __iomem *) GPIO_INT_POLARITY);
	iowrite32(GPIO_INT_CONNECTED_MASK, (void __iomem *) GPIO_INTEN);
}

static int __init hsdk_tweak_node_coherency(const char *path, bool coherent)
{
	void *fdt = initial_boot_params;

Annotation

Implementation Notes