#pypp 0
// Iris: micro-kernel for a capability-based operating system.
// source/buffer.ccp: block device buffer.
// Copyright 2010 Bas Wijnen <wijnen@debian.org>
//
// 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 3 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.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

#include "iris.hh"
#include "devices.hh"

static unsigned align
static Iris::Page page, rpage
static unsigned mapping, rmapping
static Iris::Num size, current
static Iris::String dev

static void read_block (Iris::Num idx):
	idx = idx.value () & PAGE_MASK
	if idx.value () == current.value ():
		return
	//kdebug ("buffering block ")
	//kdebug_num (idx.h)
	//kdebug (":")
	//kdebug_num (idx.l)
	//kdebug ("\n")
	dev.get_block (idx, PAGE_SIZE, 0, page)
	//kdebug ("buffered\n")
	current = idx

Iris::Num start ():
	dev = Iris::my_parent.get_capability <Iris::WString> ()
	align = dev.get_align_bits ()
	size = dev.get_size ()
	if align > PAGE_BITS:
		Iris::panic (align, "invalid alignment value for block device")
	page = Iris::my_memory.create_page ()
	rpage = Iris::my_memory.create_page ()
	page.set_flags (Iris::Page::PAYING)
	rpage.set_flags (Iris::Page::PAYING)
	mapping = 0x15000
	rmapping = 0x17000
	Iris::my_memory.map (page, mapping)
	Iris::my_memory.map (rpage, rmapping)
	current.h = ~0
	current.l = ~0
	Iris::Cap cap = Iris::my_receiver.create_capability (0)
	Iris::my_parent.provide_capability <Iris::WString> (cap.copy ())
	Iris::free_cap (cap)
	Iris::my_parent.init_done ()
	while true:
		Iris::wait ()
		switch Iris::recv.data[0].l:
			case Iris::String::GET_SIZE:
				Iris::recv.reply.invoke (size)
				break
			case Iris::String::GET_ALIGN_BITS:
				// Use 16 byte alignment to make implementing GET_CHARS easier.
				Iris::recv.reply.invoke (4)
				break
			case Iris::String::GET_CHARS:
				Iris::Cap reply = Iris::get_reply ()
				unsigned offset = Iris::recv.data[1].l & ~PAGE_MASK & ~((1 << 4) - 1)
				read_block (Iris::recv.data[1])
				unsigned *data = (unsigned *)((char *)mapping)[offset]
				reply.invoke (Iris::Num (data[0], data[1]), Iris::Num (data[2], data[3]))
				Iris::free_cap (reply)
				break
			case Iris::String::GET_BLOCK:
				Iris::Cap reply = Iris::get_reply ()
				Iris::Page arg = Iris::get_arg ()
				unsigned offset = Iris::recv.data[1].l & ~PAGE_MASK & ~((1 << 4) - 1)
				unsigned sz = Iris::recv.data[0].h >> 16
				unsigned roffset = Iris::recv.data[0].h & 0xffff
				Iris::Num idx = Iris::recv.data[1]
				arg.set_flags (Iris::Page::FRAME | Iris::Page::PAYING)
				arg.share (rpage)
				rpage.set_flags (Iris::Page::FRAME)
				read_block (idx)
				for unsigned i = 0; i < sz; ++i:
					((char *)rmapping)[roffset + i] = ((char *)mapping)[offset + i]
				rpage.set_flags (0, Iris::Page::FRAME)
				reply.invoke ()
				Iris::free_cap (reply)
				Iris::free_cap (arg)
				break
			default:
				Iris::panic (Iris::recv.data[0].l, "invalid request for buffer")