Add initial version of device memory mapping

1 files changed, 89 insertions, 0 deletions

diff --git a/common/dev.c b/common/dev.c
new file mode 100644
index 0000000..b89fe3a
--- /dev/null
+++ b/common/dev.c
@@ -0,0 +1,89 @@
+#include <apos/dev.h>
+#include <apos/vmem.h>
+
+static struct sp_reg_root pre_ram = {0};
+static struct sp_reg_root post_ram = {0};
+pm_t __pre_base = 0;
+pm_t __pre_top = 0;
+pm_t __post_base = 0;
+pm_t __post_top = 0;
+
+void init_devmem(pm_t ram_base, pm_t ram_top)
+{
+	pm_t mem_top = (pm_t)-1;
+
+	__pre_base = 0;
+	__pre_top = ram_base - 1;
+
+	__post_base = ram_top;
+	__post_top = mem_top;
+
+	size_t pre_pages = __pages(__pre_top);
+	size_t post_pages = __pages(__post_top) - __pages(__post_base);
+
+	sp_mem_init(&pre_ram, __pre_base, pre_pages);
+	sp_mem_init(&post_ram, __post_base, post_pages);
+}
+
+static int dev_alloc_wrapper(struct vm_branch *b, pm_t *offset, vm_t vaddr, uint8_t flags, enum mm_order order)
+{
+	map_vmem(b, *offset, vaddr, flags, order);
+	*offset += __o_size(order);
+	return 0;
+}
+
+static int dev_free_wrapper(struct vm_branch *b, pm_t *offset, vm_t vaddr, uint8_t flags, enum mm_order order)
+{
+	UNUSED(offset); UNUSED(flags);
+	pm_t paddr = 0;
+	enum mm_order v_order = 0;
+	stat_vmem(b, vaddr, &paddr, &v_order, 0);
+	if(order != v_order)
+		return -1;
+
+	unmap_vmem(b, vaddr);
+	return 0;
+}
+
+vm_t alloc_devmem(struct tcb *t, pm_t dev_start, size_t bytes, uint8_t flags)
+{
+	vm_t region = 0;
+	if(dev_start < __pre_top)
+		region = alloc_region(&pre_ram, bytes, 0);
+
+	if(dev_start > __post_base)
+		region = alloc_region(&post_ram, bytes, 0);
+
+	if(!region)
+		return 0;
+
+	return map_fill_region(t->b_r, &dev_alloc_wrapper, dev_start, region, bytes, flags);
+}
+
+void free_devmem(struct tcb *t, vm_t dev_start)
+{
+	pm_t dev_paddr = 0;
+	stat_vmem(t->b_r, dev_start, &dev_paddr, 0, 0);
+
+	if(dev_paddr >= __pre_top && dev_paddr <= __post_base)
+		return;
+
+	struct sp_mem *m = 0;
+	if(dev_paddr < __pre_top)
+		m = sp_used_find(&pre_ram, dev_paddr);
+	
+	if(dev_paddr > __post_base)
+		m = sp_used_find(&post_ram, dev_paddr);
+
+	if(!m)
+		return;
+
+	size_t region_size = __addr(m->end - m->start);
+	map_fill_region(t->b_r, &dev_free_wrapper, dev_paddr, dev_start, region_size, 0);
+
+	if(dev_paddr < __pre_top)
+		free_region(&pre_ram, dev_paddr);
+
+	if(dev_paddr > __post_base)
+		free_region(&post_ram, dev_paddr);
+}