Generalize ARM specific comments in devmap

The comments in devmap are very ARM specific, this generalizes them for other
architectures.

Submitted by:	Nicholas O'Brien <nickisobrien_gmail.com>
Reviewed by:	manu, philip
Sponsored by:	Axiado
Differential Revision:	https://reviews.freebsd.org/D22035
This commit is contained in:
kp 2019-10-15 23:21:52 +00:00
parent 31482d73c4
commit 038f82f772
2 changed files with 18 additions and 15 deletions

View File

@ -46,7 +46,7 @@ static boolean_t devmap_bootstrap_done = false;
* The allocated-kva (akva) devmap table and metadata. Platforms can call
* devmap_add_entry() to add static device mappings to this table using
* automatically allocated virtual addresses carved out of the top of kva space.
* Allocation begins immediately below the ARM_VECTORS_HIGH address.
* Allocation begins immediately below the max kernel virtual address.
*/
#define AKVA_DEVMAP_MAX_ENTRIES 32
static struct devmap_entry akva_devmap_entries[AKVA_DEVMAP_MAX_ENTRIES];
@ -115,8 +115,8 @@ devmap_lastaddr()
* physical address and size and a virtual address allocated from the top of
* kva. This automatically registers the akva table on the first call, so all a
* platform has to do is call this routine to install as many mappings as it
* needs and when initarm() calls devmap_bootstrap() it will pick up all the
* entries in the akva table automatically.
* needs and when the platform-specific init function calls devmap_bootstrap()
* it will pick up all the entries in the akva table automatically.
*/
void
devmap_add_entry(vm_paddr_t pa, vm_size_t sz)
@ -132,13 +132,13 @@ devmap_add_entry(vm_paddr_t pa, vm_size_t sz)
if (akva_devmap_idx == 0)
devmap_register_table(akva_devmap_entries);
/*
* Allocate virtual address space from the top of kva downwards. If the
* range being mapped is aligned and sized to 1MB boundaries then also
* align the virtual address to the next-lower 1MB boundary so that we
* end up with a nice efficient section mapping.
*/
/* Allocate virtual address space from the top of kva downwards. */
#ifdef __arm__
/*
* If the range being mapped is aligned and sized to 1MB boundaries then
* also align the virtual address to the next-lower 1MB boundary so that
* we end with a nice efficient section mapping.
*/
if ((pa & 0x000fffff) == 0 && (sz & 0x000fffff) == 0) {
akva_devmap_vaddr = trunc_1mpage(akva_devmap_vaddr - sz);
} else
@ -170,7 +170,8 @@ devmap_register_table(const struct devmap_entry *table)
* the previously-registered table is used. This smooths transition from legacy
* code that fills in a local table then calls this function passing that table,
* and newer code that uses devmap_register_table() in platform-specific
* code, then lets the common initarm() call this function with a NULL pointer.
* code, then lets the common platform-specific init function call this function
* with a NULL pointer.
*/
void
devmap_bootstrap(vm_offset_t l1pt, const struct devmap_entry *table)

View File

@ -63,16 +63,18 @@ void devmap_add_entry(vm_paddr_t pa, vm_size_t sz);
/*
* Register a platform-local table to be bootstrapped by the generic
* initarm() in arm/machdep.c. This is used by newer code that allocates and
* fills in its own local table but does not have its own initarm() routine.
* platform-specific init function in <ARCH>/machdep.c. This is used by newer
* code that allocates and fills in its own local table but does not have its
* own platform-specific init routine.
*/
void devmap_register_table(const struct devmap_entry * _table);
/*
* Establish mappings for all the entries in the table. This is called
* automatically from the common initarm() in arm/machdep.c, and also from the
* custom initarm() routines in older code. If the table pointer is NULL, this
* will use the table installed previously by devmap_register_table().
* automatically from the common platform-specific init function in
* <ARCH>/machdep.c, and also from the custom platform-specific init routines
* in older code. If the table pointer is NULL, this will use the table
* installed previously by devmap_register_table().
*/
void devmap_bootstrap(vm_offset_t _l1pt,
const struct devmap_entry *_table);