[patch v3 16/36] Hexagon: Add startup code

Richard Kuo
2011-09-09T01:11:11Z

[-- Attachment #1: startup.diff --]
[-- Type: text/plain, Size: 10634 bytes --]

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>

---
arch/hexagon/kernel/head.S | 162 ++++++++++++++++++++++++++++++++++++++++++++
arch/hexagon/kernel/reset.c | 38 ++++++++++
arch/hexagon/kernel/setup.c | 145 +++++++++++++++++++++++++++++++++++++++
3 files changed, 345 insertions(+)

Index: linux-hexagon-kernel/arch/hexagon/kernel/head.S
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-hexagon-kernel/arch/hexagon/kernel/head.S 2011-09-07 13:00:31.040646956 -0500
@@ -0,0 +1,162 @@
+/*
+ * Early kernel startup code for Hexagon
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/asm-offsets.h>
+#include <asm/mem-layout.h>
+#include <asm/vm_mmu.h>
+#include <asm/page.h>
+
+ __INIT
+ENTRY(stext)
+ /*
+ * VMM will already have set up true vector page, MMU, etc.
+ * To set up initial kernel identity map, we have to pass
+ * the VMM a pointer to some canonical page tables. In
+ * this implementation, we're assuming that we've got
+ * them precompiled. Generate value in R24, as we'll need
+ * it again shortly.
+ */
+ r24.L = #LO(swapper_pg_dir)
+ r24.H = #HI(swapper_pg_dir)
+
+ /*
+ * Symbol is kernel segment address, but we need
+ * the logical/physical address.
+ */
+ r24 = asl(r24, #2)
+ r24 = lsr(r24, #2)
+
+ r0 = r24
+
+ /*
+ * Initialize a 16MB PTE to make the virtual and physical
+ * addresses where the kernel was loaded be identical.
+ */
+#define PTE_BITS ( __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X \
+ | __HEXAGON_C_WB_L2 << 6 \
+ | __HVM_PDE_S_4MB)
+
+ r1 = pc
+ r2.H = #0xffc0
+ r2.L = #0x0000
+ r1 = and(r1,r2) /* round PC to 4MB boundary */
+ r2 = lsr(r1, #22) /* 4MB page number */
+ r2 = asl(r2, #2) /* times sizeof(PTE) (4bytes) */
+ r0 = add(r0,r2) /* r0 = address of correct PTE */
+ r2 = #PTE_BITS
+ r1 = add(r1,r2) /* r1 = 4MB PTE for the first entry */
+ r2.h = #0x0040
+ r2.l = #0x0000 /* 4MB */
+ memw(r0 ++ #4) = r1
+ r1 = add(r1, r2)
+ memw(r0 ++ #4) = r1
+
+ r0 = r24
+
+ /*
+ * The subroutine wrapper around the virtual instruction touches
+ * no memory, so we should be able to use it even here.
+ */
+ call __vmnewmap;
+
+ /* Jump into virtual address range. */
+
+ r31.h = #hi(__head_s_vaddr_target)
+ r31.l = #lo(__head_s_vaddr_target)
+ jumpr r31
+
+ /* Insert trippy space effects. */
+
+__head_s_vaddr_target:
+ /*
+ * Tear down VA=PA translation now that we are running
+ * in the desgnated kernel segments.
+ */
+ r0 = #__HVM_PDE_S_INVALID
+ r1 = r24
+ loop0(1f,#0x100)
+1:
+ {
+ memw(R1 ++ #4) = R0
+ }:endloop0
+
+ r0 = r24
+ call __vmnewmap
+
+ /* Go ahead and install the trap0 return so angel calls work */
+ r0.h = #hi(_K_provisional_vec)
+ r0.l = #lo(_K_provisional_vec)
+ call __vmsetvec
+
+ /*
+ * OK, at this point we should start to be much more careful,
+ * we're going to enter C code and start touching memory
+ * in all sorts of places.
+ * This means:
+ * SGP needs to be OK
+ * Need to lock shared resources
+ * A bunch of other things that will cause
+ * all kinds of painful bugs
+ */
+
+ /*
+ * Stack pointer should be pointed at the init task's
+ * thread stack, which should have been declared in arch/init_task.c.
+ * So uhhhhh...
+ * It's accessible via the init_thread_union, which is a union
+ * of a thread_info struct and a stack; of course, the top
+ * of the stack is not for you. The end of the stack
+ * is simply init_thread_union + THREAD_SIZE.
+ */
+
+ {r29.H = #HI(init_thread_union); r0.H = #HI(_THREAD_SIZE); }
+ {r29.L = #LO(init_thread_union); r0.L = #LO(_THREAD_SIZE); }
+
+ /* initialize the register used to point to current_thread_info */
+ /* Fixme: THREADINFO_REG can't be R2 because of that memset thing. */
+ {r29 = add(r29,r0); THREADINFO_REG = r29; }
+
+ /* Hack: zero bss; */
+ { r0.L = #LO(__bss_start); r1 = #0; r2.l = #LO(__bss_stop); }
+ { r0.H = #HI(__bss_start); r2.h = #HI(__bss_stop); }
+
+ r2 = sub(r2,r0);
+ call memset;
+
+ /* Time to make the doughnuts. */
+ call start_kernel
+
+ /*
+ * Should not reach here.
+ */
+1:
+ jump 1b
+
+.p2align PAGE_SHIFT
+ENTRY(external_cmdline_buffer)
+ .fill _PAGE_SIZE,1,0
+
+.data
+.p2align PAGE_SHIFT
+ENTRY(empty_zero_page)
+ .fill _PAGE_SIZE,1,0
Index: linux-hexagon-kernel/arch/hexagon/kernel/reset.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-hexagon-kernel/arch/hexagon/kernel/reset.c 2011-09-03 20:14:59.644981167 -0500
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/smp.h>
+#include <asm/hexagon_vm.h>
+
+void machine_power_off(void)
+{
+ smp_send_stop();
+ __vmstop();
+}
+
+void machine_halt(void)
+{
+}
+
+void machine_restart(char *cmd)
+{
+}
+
+void pm_power_off(void)
+{
+}
Index: linux-hexagon-kernel/arch/hexagon/kernel/setup.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-hexagon-kernel/arch/hexagon/kernel/setup.c 2011-09-07 13:00:31.120647076 -0500
@@ -0,0 +1,145 @@
+/*
+ * Arch related setup for Hexagon
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/mmzone.h>
+#include <linux/mm.h>
+#include <linux/seq_file.h>
+#include <linux/console.h>
+#include <linux/of_fdt.h>
+#include <asm/io.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/processor.h>
+#include <asm/hexagon_vm.h>
+#include <asm/vm_mmu.h>
+#include <asm/time.h>
+#ifdef CONFIG_OF
+#include <asm/prom.h>
+#endif
+
+char cmd_line[COMMAND_LINE_SIZE];
+static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE;
+
+int on_simulator;
+
+void __cpuinit calibrate_delay(void)
+{
+ loops_per_jiffy = thread_freq_mhz * 1000000 / HZ;
+}
+
+/*
+ * setup_arch - high level architectural setup routine
+ * @cmdline_p: pointer to pointer to command-line arguments
+ */
+
+void __init setup_arch(char **cmdline_p)
+{
+ char *p = &external_cmdline_buffer;
+
+ /*
+ * These will eventually be pulled in via either some hypervisor
+ * or devicetree description. Hardwiring for now.
+ */
+ pcycle_freq_mhz = 600;
+ thread_freq_mhz = 100;
+ sleep_clk_freq = 32000;
+
+ /*
+ * Set up event bindings to handle exceptions and interrupts.
+ */
+ __vmsetvec(_K_VM_event_vector);
+
+ /*
+ * Simulator has a few differences from the hardware.
+ * For now, check uninitialized-but-mapped memory
+ * prior to invoking setup_arch_memory().
+ */
+ if (*(int *)((unsigned long)_end + 8) == 0x1f1f1f1f)
+ on_simulator = 1;
+ else
+ on_simulator = 0;
+
+ if (p[0] != '\0')
+ strlcpy(boot_command_line, p, COMMAND_LINE_SIZE);
+ else
+ strlcpy(boot_command_line, default_command_line,
+ COMMAND_LINE_SIZE);
+
+ /*
+ * boot_command_line and the value set up by setup_arch
+ * are both picked up by the init code. If no reason to
+ * make them different, pass the same pointer back.
+ */
+ strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
+ *cmdline_p = cmd_line;
+
+ parse_early_param();
+
+ setup_arch_memory();
+
+#ifdef CONFIG_SMP
+ smp_start_cpus();
+#endif
+}
+
+/*
+ * Functions for dumping CPU info via /proc
+ * Probably should move to kernel/proc.c or something.
+ */
+static void *c_start(struct seq_file *m, loff_t *pos)
+{
+ return *pos < nr_cpu_ids ? (void *)((unsigned long) *pos + 1) : NULL;
+}
+
+static void *c_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ ++*pos;
+ return c_start(m, pos);
+}
+
+static void c_stop(struct seq_file *m, void *v)
+{
+}
+
+/*
+ * Eventually this will dump information about
+ * CPU properties like ISA level, TLB size, etc.
+ */
+static int show_cpuinfo(struct seq_file *m, void *v)
+{
+ int cpu = (unsigned long) v - 1;
+
+ seq_printf(m, "processor\t: %d\n", cpu);
+ seq_printf(m, "model name\t: Hexagon Virtual Machine\n");
+ seq_printf(m, "BogoMips\t: %lu.%02lu\n",
+ (loops_per_jiffy * HZ) / 500000,
+ ((loops_per_jiffy * HZ) / 5000) % 100);
+ seq_printf(m, "\n");
+ return 0;
+}
+
+const struct seq_operations cpuinfo_op = {
+ .start = &c_start,
+ .next = &c_next,
+ .stop = &c_stop,
+ .show = &show_cpuinfo,
+};