[Xen-devel] [PATCH v6 04/10] xen/arm: introduce early_ioremap

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Introduce a function to map a range of physical memory into Xen virtual
memory.
It doesn't need domheap to be setup.
It is going to be used to map the videoram.


Changes in v5:
- move out of this patch any changes related to
flush_xen_data_tlb_range_va and PAGE masks.

Changes in v4:
- rename flush_xen_data_tlb_range to flush_xen_data_tlb_range_va;
- replace all the calls to flush_xen_data_tlb_va, with calls to
flush_xen_data_tlb_range_va;
- flush the entire 2MB mapping at BOOT_MISC_VIRT_START rather than just
the first 4k;
- remove flush_xen_data_tlb_va;
- fix indentation;
- rename EARLY_VMAP_START/END to EARLY_VMAP_VIRT_START/END;
- mark early_ioremap as __init;
- reduce the amount of casts in early_ioremap.


Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 xen/arch/arm/mm.c            |   32 ++++++++++++++++++++++++++++++++
 xen/include/asm-arm/config.h |    4 ++++
 xen/include/asm-arm/mm.h     |    3 ++-
 3 files changed, 38 insertions(+), 1 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 2140777..acb6771 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -393,6 +393,38 @@ void __init setup_frametable_mappings(paddr_t ps, paddr_t 
pe)
     frametable_virt_end = FRAMETABLE_VIRT_START + (nr_pages * sizeof(struct 
page_info));
 }
 
+/* Map the physical memory range start -  start + len into virtual
+ * memory and return the virtual address of the mapping.
+ * start has to be 2MB aligned.
+ * len has to be < EARLY_VMAP_VIRT_END - EARLY_VMAP_VIRT_START.
+ */
+void* __init early_ioremap(paddr_t start, size_t len, unsigned attributes)
+{
+    static unsigned long virt_start = EARLY_VMAP_VIRT_START;
+    unsigned long ret_addr = virt_start;
+    paddr_t end = start + len;
+
+    ASSERT(!(start & (~SECOND_MASK)));
+    ASSERT(!(virt_start & (~SECOND_MASK)));
+
+    /* The range we need to map is too big */
+    if ( virt_start + len >= EARLY_VMAP_VIRT_END )
+        return NULL;
+
+    while ( start < end )
+    {
+        lpae_t e = mfn_to_xen_entry(start >> PAGE_SHIFT);
+        e.pt.ai = attributes;
+        write_pte(xen_second + second_table_offset(virt_start), e);
+
+        start += SECOND_SIZE;
+        virt_start += SECOND_SIZE;
+    }
+    flush_xen_data_tlb_range_va(ret_addr, len);
+
+    return (void*)ret_addr;
+}
+
 enum mg { mg_clear, mg_ro, mg_rw, mg_rx };
 static void set_pte_flags_on_range(const char *p, unsigned long l, enum mg mg)
 {
diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h
index 2a05539..e5dce5e 100644
--- a/xen/include/asm-arm/config.h
+++ b/xen/include/asm-arm/config.h
@@ -60,6 +60,8 @@
  *  6M  -  8M   Early boot misc (see below)
  *
  * 32M - 128M   Frametable: 24 bytes per page for 16GB of RAM
+ * 256M -  1G   VMAP: ioremap and early_ioremap use this virtual address
+ *                    space
  *
  *  1G -   2G   Xenheap: always-mapped memory
  *  2G -   4G   Domheap: on-demand-mapped
@@ -73,9 +75,11 @@
 #define FIXMAP_ADDR(n)        (mk_unsigned_long(0x00400000) + (n) * PAGE_SIZE)
 #define BOOT_MISC_VIRT_START   mk_unsigned_long(0x00600000)
 #define FRAMETABLE_VIRT_START  mk_unsigned_long(0x02000000)
+#define EARLY_VMAP_VIRT_START  mk_unsigned_long(0x10000000)
 #define XENHEAP_VIRT_START     mk_unsigned_long(0x40000000)
 #define DOMHEAP_VIRT_START     mk_unsigned_long(0x80000000)
 
+#define EARLY_VMAP_VIRT_END    XENHEAP_VIRT_START
 #define HYPERVISOR_VIRT_START  XEN_VIRT_START
 
 #define DOMHEAP_ENTRIES        1024  /* 1024 2MB mapping slots */
diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
index e95ece1..4ed5df6 100644
--- a/xen/include/asm-arm/mm.h
+++ b/xen/include/asm-arm/mm.h
@@ -150,7 +150,8 @@ extern void setup_frametable_mappings(paddr_t ps, paddr_t 
pe);
 extern void set_fixmap(unsigned map, unsigned long mfn, unsigned attributes);
 /* Remove a mapping from a fixmap entry */
 extern void clear_fixmap(unsigned map);
-
+/* map a 2MB aligned physical range in virtual memory. */
+void* early_ioremap(paddr_t start, size_t len, unsigned attributes);
 
 #define mfn_valid(mfn)        ({                                              \
     unsigned long __m_f_n = (mfn);                                            \
-- 
1.7.2.5


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