[Xen-devel] [RFC 22/29] xen/arm: Allow Xen to run on multiple platform without recompilation

[Julien Grall <julien.grall@xxxxxxxxxx>]

Xen can include various platform support (ie: exynos5, versatile express...)
and choose during boot time a set of callbacks for the current board.
These callbacks will be called in places where each board can have specific
code. For the moment the callbacks are:
  - platform_init: additional initialization for the platform
  - platform_init_time: some platform (ie: Exynos 5) needs to initialize
  the timer with an uncommon way
  - platform_specific_mapping: add mapping to dom0 which are not specified
  in the device tree
  - platform_reset: reset the platform

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
 xen/arch/arm/Makefile          |    1 +
 xen/arch/arm/domain_build.c    |    4 ++
 xen/arch/arm/platform.c        |  121 ++++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/setup.c           |    3 +
 xen/arch/arm/shutdown.c        |    2 +
 xen/arch/arm/time.c            |    6 ++
 xen/arch/arm/xen.lds.S         |    6 ++
 xen/include/asm-arm/platform.h |   70 +++++++++++++++++++++++
 8 files changed, 213 insertions(+)
 create mode 100644 xen/arch/arm/platform.c
 create mode 100644 xen/include/asm-arm/platform.h

diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 7a73b79..981ad78 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -17,6 +17,7 @@ obj-y += p2m.o
 obj-y += percpu.o
 obj-y += guestcopy.o
 obj-y += physdev.o
+obj-y += platform.o
 obj-y += setup.o
 obj-y += time.o
 obj-y += smpboot.o
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 11298e1..d6b8086 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -12,6 +12,7 @@
 #include <xen/libfdt/libfdt.h>
 #include <xen/guest_access.h>
 #include <asm/setup.h>
+#include <asm/platform.h>
 
 #include <asm/gic.h>
 #include <xen/irq.h>
@@ -516,6 +517,9 @@ int construct_dom0(struct domain *d)
         return rc;
 
     parse_device_tree(d);
+    rc = platform_specific_mapping(d);
+    if ( rc < 0 )
+        return rc;
 
     /* The following loads use the domain's p2m */
     p2m_load_VTTBR(d);
diff --git a/xen/arch/arm/platform.c b/xen/arch/arm/platform.c
new file mode 100644
index 0000000..ba569ea
--- /dev/null
+++ b/xen/arch/arm/platform.c
@@ -0,0 +1,121 @@
+/*
+ * xen/arch/arm/platform.c
+ *
+ * Helpers to execute platform specific code.
+ *
+ * Julien Grall <julien.grall@xxxxxxxxxx>
+ * Copyright (C) 2013 Linaro Limited.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+#include <asm/platform.h>
+#include <xen/device_tree.h>
+#include <xen/init.h>
+
+extern const struct platform_desc _splatform[], _eplatform[];
+
+/* Pointer to the current platform description */
+static const struct platform_desc *platform;
+
+
+static bool_t __init platform_is_compatible(const struct platform_desc *plat)
+{
+    const char *const *compat;
+
+    if ( !plat->compatible )
+        return 0;
+
+    for ( compat = plat->compatible; *compat; compat++ )
+    {
+        if ( dt_machine_is_compatible(*compat) )
+            return 1;
+    }
+
+    return 0;
+}
+
+/* List of possible platform */
+static void dump_platform_table(void)
+{
+    const struct platform_desc *p;
+
+    printk("Available platform support:\n");
+
+    for ( p = _splatform; p != _eplatform; p++ )
+        printk("    - %s\n", p->name);
+}
+
+int __init platform_init(void)
+{
+    int res = 0;
+
+    ASSERT(platform == NULL);
+
+    /* Looking for the platform description */
+    for ( platform = _splatform; platform != _eplatform; platform++ )
+    {
+        if ( platform_is_compatible(platform) )
+            break;
+    }
+
+    /* We don't have specific operations for this platform */
+    if ( platform == _eplatform )
+    {
+        /* TODO: List compatible */
+        printk(XENLOG_WARNING "WARNING: Unrecognized/unsupported device tree "
+              "compatible list\n");
+        dump_platform_table();
+        platform = NULL;
+    }
+    else
+        printk(XENLOG_INFO "Platform: %s\n", platform->name);
+
+    if ( platform && platform->init )
+        res = platform->init();
+
+    return res;
+}
+
+int __init platform_init_time(void)
+{
+    int res = 0;
+
+    if ( platform && platform->init_time )
+        res = platform->init_time();
+
+    return res;
+}
+
+int __init platform_specific_mapping(struct domain *d)
+{
+    int res = 0;
+
+    if ( platform && platform->specific_mapping )
+        res = platform->specific_mapping(d);
+
+    return res;
+}
+
+void platform_reset(void)
+{
+    if ( platform && platform->reset )
+        platform->reset();
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index aee491d..9721150 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -41,6 +41,7 @@
 #include <asm/early_printk.h>
 #include <asm/gic.h>
 #include <asm/cpufeature.h>
+#include <asm/platform.h>
 
 struct cpuinfo_arm __read_mostly boot_cpu_data;
 
@@ -439,6 +440,8 @@ void __init start_xen(unsigned long boot_phys_offset,
 
     processor_id();
 
+    platform_init();
+
     init_xen_time();
 
     gic_init();
diff --git a/xen/arch/arm/shutdown.c b/xen/arch/arm/shutdown.c
index c1b60af..a5c2085 100644
--- a/xen/arch/arm/shutdown.c
+++ b/xen/arch/arm/shutdown.c
@@ -5,6 +5,7 @@
 #include <xen/lib.h>
 #include <xen/mm.h>
 #include <xen/smp.h>
+#include <asm/platform.h>
 
 static void raw_machine_reset(void)
 {
@@ -21,6 +22,7 @@ static void raw_machine_reset(void)
     dsb(); isb();
     clear_fixmap(FIXMAP_MISC);
 #endif
+    platform_reset();
 }
 
 static void halt_this_cpu(void *arg)
diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index 63dace2..f01be3f 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -33,6 +33,7 @@
 #include <asm/time.h>
 #include <asm/gic.h>
 #include <asm/cpufeature.h>
+#include <asm/platform.h>
 
 /*
  * Unfortunately the hypervisor timer interrupt appears to be buggy in
@@ -130,6 +131,11 @@ int __init init_xen_time(void)
         panic("CPU does not support the Generic Timer v1 interface.\n");
 
     cpu_khz = READ_SYSREG32(CNTFRQ_EL0) / 1000;
+
+    res = platform_init_time();
+    if ( res )
+        return res;
+
     boot_count = READ_SYSREG64(CNTPCT_EL0);
     printk("Using generic timer at %lu KHz\n", cpu_khz);
 
diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index 7434e83..b5c99b7 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -76,6 +76,12 @@ SECTIONS
   __lock_profile_end = .;
 #endif
 
+  .arch.info : {
+      _splatform = .;
+      *(.arch.info)
+      _eplatform = .;
+  } :text
+
   .dev.info : {
       _sdevice = .;
       *(.dev.info)
diff --git a/xen/include/asm-arm/platform.h b/xen/include/asm-arm/platform.h
new file mode 100644
index 0000000..c89a4ca
--- /dev/null
+++ b/xen/include/asm-arm/platform.h
@@ -0,0 +1,70 @@
+#ifndef __ASM_ARM_PLATFORM_H
+#define __ASM_ARM_PLATFORM_H
+
+#include <xen/init.h>
+#include <xen/sched.h>
+#include <xen/mm.h>
+
+/* Describe specific operation for a board */
+struct platform_desc {
+    /* Platform name */
+    const char *name;
+    /* Array of device tree 'compatible' strings */
+    const char *const *compatible;
+    /* Platform initialization */
+    int (*init)(void);
+    int (*init_time)(void);
+    /* Specific mapping for dom0 */
+    int (*specific_mapping)(struct domain *d);
+    /* Platform reset */
+    void (*reset)(void);
+};
+
+int __init platform_init(void);
+int __init platform_init_time(void);
+int __init platform_specific_mapping(struct domain *d);
+void platform_reset(void);
+
+/* Helper to read/write a register */
+static inline uint32_t platform_read_register(uint32_t addr)
+{
+    volatile const uint32_t *reg;
+    uint32_t value;
+
+    set_fixmap(FIXMAP_MISC, addr >> PAGE_SHIFT, DEV_SHARED);
+    reg = (uint32_t *)(FIXMAP_ADDR(FIXMAP_MISC) + (addr & ~PAGE_MASK));
+    value = *reg;
+    dsb(); isb();
+    clear_fixmap(FIXMAP_MISC);
+
+    return value;
+}
+
+static inline void platform_write_register(uint32_t addr, uint32_t value)
+{
+    volatile uint32_t *reg;
+
+    set_fixmap(FIXMAP_MISC, addr >> PAGE_SHIFT, DEV_SHARED);
+    reg = (uint32_t *)(FIXMAP_ADDR(FIXMAP_MISC) + (addr & ~PAGE_MASK));
+    *reg = value;
+    clear_fixmap(FIXMAP_MISC);
+}
+
+#define PLATFORM_START(_name, _namestr)                         \
+static const struct platform_desc  __plat_desc_##_name __used   \
+__attribute__((__section__(".arch.info"))) = {                  \
+    .name = _namestr,
+
+#define PLATFORM_END                                            \
+};
+
+#endif /* __ASM_ARM_PLATFORM_H */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
Julien Grall


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel