malta-dtshim.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2015 Imagination Technologies
* Author: Paul Burton <paul.burton@mips.com>
*/
#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/libfdt.h>
#include <linux/of_fdt.h>
#include <linux/sizes.h>
#include <asm/addrspace.h>
#include <asm/bootinfo.h>
#include <asm/fw/fw.h>
#include <asm/mips-boards/generic.h>
#include <asm/mips-boards/malta.h>
#include <asm/mips-cps.h>
#include <asm/page.h>
#define ROCIT_REG_BASE 0x1f403000
#define ROCIT_CONFIG_GEN1 (ROCIT_REG_BASE + 0x04)
#define ROCIT_CONFIG_GEN1_MEMMAP_SHIFT 8
#define ROCIT_CONFIG_GEN1_MEMMAP_MASK (0xf << 8)
static unsigned char fdt_buf[16 << 10] __initdata __aligned(8);
/* determined physical memory size, not overridden by command line args */
extern unsigned long physical_memsize;
enum mem_map {
MEM_MAP_V1 = 0,
MEM_MAP_V2,
};
#define MAX_MEM_ARRAY_ENTRIES 2
static __init int malta_scon(void)
{
int scon = MIPS_REVISION_SCONID;
if (scon != MIPS_REVISION_SCON_OTHER)
return scon;
switch (MIPS_REVISION_CORID) {
case MIPS_REVISION_CORID_QED_RM5261:
case MIPS_REVISION_CORID_CORE_LV:
case MIPS_REVISION_CORID_CORE_FPGA:
case MIPS_REVISION_CORID_CORE_FPGAR2:
return MIPS_REVISION_SCON_GT64120;
case MIPS_REVISION_CORID_CORE_EMUL_BON:
case MIPS_REVISION_CORID_BONITO64:
case MIPS_REVISION_CORID_CORE_20K:
return MIPS_REVISION_SCON_BONITO;
case MIPS_REVISION_CORID_CORE_MSC:
case MIPS_REVISION_CORID_CORE_FPGA2:
case MIPS_REVISION_CORID_CORE_24K:
return MIPS_REVISION_SCON_SOCIT;
case MIPS_REVISION_CORID_CORE_FPGA3:
case MIPS_REVISION_CORID_CORE_FPGA4:
case MIPS_REVISION_CORID_CORE_FPGA5:
case MIPS_REVISION_CORID_CORE_EMUL_MSC:
default:
return MIPS_REVISION_SCON_ROCIT;
}
}
static unsigned __init gen_fdt_mem_array(__be32 *mem_array, unsigned long size,
enum mem_map map)
{
unsigned long size_preio;
unsigned entries;
entries = 1;
mem_array[0] = cpu_to_be32(PHYS_OFFSET);
if (IS_ENABLED(CONFIG_EVA)) {
/*
* The current Malta EVA configuration is "special" in that it
* always makes use of addresses in the upper half of the 32 bit
* physical address map, which gives it a contiguous region of
* DDR but limits it to 2GB.
*/
mem_array[1] = cpu_to_be32(size);
goto done;
}
size_preio = min_t(unsigned long, size, SZ_256M);
mem_array[1] = cpu_to_be32(size_preio);
size -= size_preio;
if (!size)
goto done;
if (map == MEM_MAP_V2) {
/*
* We have a flat 32 bit physical memory map with DDR filling
* all 4GB of the memory map, apart from the I/O region which
* obscures 256MB from 0x10000000-0x1fffffff.
*
* Therefore we discard the 256MB behind the I/O region.
*/
if (size <= SZ_256M)
goto done;
size -= SZ_256M;
/* Make use of the memory following the I/O region */
entries++;
mem_array[2] = cpu_to_be32(PHYS_OFFSET + SZ_512M);
mem_array[3] = cpu_to_be32(size);
} else {
/*
* We have a 32 bit physical memory map with a 2GB DDR region
* aliased in the upper & lower halves of it. The I/O region
* obscures 256MB from 0x10000000-0x1fffffff in the low alias
* but the DDR it obscures is accessible via the high alias.
*
* Simply access everything beyond the lowest 256MB of DDR using
* the high alias.
*/
entries++;
mem_array[2] = cpu_to_be32(PHYS_OFFSET + SZ_2G + SZ_256M);
mem_array[3] = cpu_to_be32(size);
}
done:
BUG_ON(entries > MAX_MEM_ARRAY_ENTRIES);
return entries;
}
static void __init append_memory(void *fdt, int root_off)
{
__be32 mem_array[2 * MAX_MEM_ARRAY_ENTRIES];
unsigned long memsize;
unsigned mem_entries;
int i, err, mem_off;
enum mem_map mem_map;
u32 config;
char *var, param_name[10], *var_names[] = {
"ememsize", "memsize",
};
/* if a memory node already exists, leave it alone */
mem_off = fdt_path_offset(fdt, "/memory");
if (mem_off >= 0)
return;
/* find memory size from the bootloader environment */
for (i = 0; i < ARRAY_SIZE(var_names); i++) {
var = fw_getenv(var_names[i]);
if (!var)
continue;
err = kstrtoul(var, 0, &physical_memsize);
if (!err)
break;
pr_warn("Failed to read the '%s' env variable '%s'\n",
var_names[i], var);
}
if (!physical_memsize) {
pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n");
physical_memsize = 32 << 20;
}
if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) {
/*
* SOC-it swaps, or perhaps doesn't swap, when DMA'ing
* the last word of physical memory.
*/
physical_memsize -= PAGE_SIZE;
}
/* default to using all available RAM */
memsize = physical_memsize;
/* allow the user to override the usable memory */
for (i = 0; i < ARRAY_SIZE(var_names); i++) {
snprintf(param_name, sizeof(param_name), "%s=", var_names[i]);
var = strstr(arcs_cmdline, param_name);
if (!var)
continue;
memsize = memparse(var + strlen(param_name), NULL);
}
/* if the user says there's more RAM than we thought, believe them */
physical_memsize = max_t(unsigned long, physical_memsize, memsize);
/* detect the memory map in use */
if (malta_scon() == MIPS_REVISION_SCON_ROCIT) {
/* ROCit has a register indicating the memory map in use */
config = readl((void __iomem *)CKSEG1ADDR(ROCIT_CONFIG_GEN1));
mem_map = config & ROCIT_CONFIG_GEN1_MEMMAP_MASK;
mem_map >>= ROCIT_CONFIG_GEN1_MEMMAP_SHIFT;
} else {
/* if not using ROCit, presume the v1 memory map */
mem_map = MEM_MAP_V1;
}
if (mem_map > MEM_MAP_V2)
panic("Unsupported physical memory map v%u detected",
(unsigned int)mem_map);
/* append memory to the DT */
mem_off = fdt_add_subnode(fdt, root_off, "memory");
if (mem_off < 0)
panic("Unable to add memory node to DT: %d", mem_off);
err = fdt_setprop_string(fdt, mem_off, "device_type", "memory");
if (err)
panic("Unable to set memory node device_type: %d", err);
mem_entries = gen_fdt_mem_array(mem_array, physical_memsize, mem_map);
err = fdt_setprop(fdt, mem_off, "reg", mem_array,
mem_entries * 2 * sizeof(mem_array[0]));
if (err)
panic("Unable to set memory regs property: %d", err);
mem_entries = gen_fdt_mem_array(mem_array, memsize, mem_map);
err = fdt_setprop(fdt, mem_off, "linux,usable-memory", mem_array,
mem_entries * 2 * sizeof(mem_array[0]));
if (err)
panic("Unable to set linux,usable-memory property: %d", err);
}
static void __init remove_gic(void *fdt)
{
int err, gic_off, i8259_off, cpu_off;
void __iomem *biu_base;
uint32_t cpu_phandle, sc_cfg;
/* if we have a CM which reports a GIC is present, leave the DT alone */
err = mips_cm_probe();
if (!err && (read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX))
return;
if (malta_scon() == MIPS_REVISION_SCON_ROCIT) {
/*
* On systems using the RocIT system controller a GIC may be
* present without a CM. Detect whether that is the case.
*/
biu_base = ioremap(MSC01_BIU_REG_BASE,
MSC01_BIU_ADDRSPACE_SZ);
sc_cfg = __raw_readl(biu_base + MSC01_SC_CFG_OFS);
if (sc_cfg & MSC01_SC_CFG_GICPRES_MSK) {
/* enable the GIC at the system controller level */
sc_cfg |= BIT(MSC01_SC_CFG_GICENA_SHF);
__raw_writel(sc_cfg, biu_base + MSC01_SC_CFG_OFS);
return;
}
}
gic_off = fdt_node_offset_by_compatible(fdt, -1, "mti,gic");
if (gic_off < 0) {
pr_warn("malta-dtshim: unable to find DT GIC node: %d\n",
gic_off);
return;
}
err = fdt_nop_node(fdt, gic_off);
if (err)
pr_warn("malta-dtshim: unable to nop GIC node\n");
i8259_off = fdt_node_offset_by_compatible(fdt, -1, "intel,i8259");
if (i8259_off < 0) {
pr_warn("malta-dtshim: unable to find DT i8259 node: %d\n",
i8259_off);
return;
}
cpu_off = fdt_node_offset_by_compatible(fdt, -1,
"mti,cpu-interrupt-controller");
if (cpu_off < 0) {
pr_warn("malta-dtshim: unable to find CPU intc node: %d\n",
cpu_off);
return;
}
cpu_phandle = fdt_get_phandle(fdt, cpu_off);
if (!cpu_phandle) {
pr_warn("malta-dtshim: unable to get CPU intc phandle\n");
return;
}
err = fdt_setprop_u32(fdt, i8259_off, "interrupt-parent", cpu_phandle);
if (err) {
pr_warn("malta-dtshim: unable to set i8259 interrupt-parent: %d\n",
err);
return;
}
err = fdt_setprop_u32(fdt, i8259_off, "interrupts", 2);
if (err) {
pr_warn("malta-dtshim: unable to set i8259 interrupts: %d\n",
err);
return;
}
}
void __init *malta_dt_shim(void *fdt)
{
int root_off, len, err;
const char *compat;
if (fdt_check_header(fdt))
panic("Corrupt DT");
err = fdt_open_into(fdt, fdt_buf, sizeof(fdt_buf));
if (err)
panic("Unable to open FDT: %d", err);
root_off = fdt_path_offset(fdt_buf, "/");
if (root_off < 0)
panic("No / node in DT");
compat = fdt_getprop(fdt_buf, root_off, "compatible", &len);
if (!compat)
panic("No root compatible property in DT: %d", len);
/* if this isn't Malta, leave the DT alone */
if (strncmp(compat, "mti,malta", len))
return fdt;
append_memory(fdt_buf, root_off);
remove_gic(fdt_buf);
err = fdt_pack(fdt_buf);
if (err)
panic("Unable to pack FDT: %d\n", err);
return fdt_buf;
}