From: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Date: Sat, 22 May 2010 10:05:48 +0000 (-0400)
Subject: How to do I/O.
X-Git-Url: http://git.cascardo.eti.br/?p=cascardo%2Fkernel%2Fslides%2F.git;a=commitdiff_plain;h=db61ca31b33974b92c426d9278a5e5ffa704035b

How to do I/O.
---

diff --git a/11io/io b/11io/io
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+%I/O
+%Thadeu Cascardo
+
+# I/O Ports versus Memory Mapped Devices
+
+* Separate I/O space in x86 architecture
+* Other architectures emulate this I/O space access
+
+# Resource allocation
+
+* Different drivers must not conflict when using device resources, like I/O
+  ports or memory space
+* They must request these resources and release them
+
+# I/O port allocation
+
+* linux/ioport.h
+* request\\_region(port, num, name)
+* release\\_region(port, num)
+* /proc/ioports
+
+# I/O ports access
+
+* asm/io.h
+* inb(port)
+* outb(data, port)
+* inw(port)
+* outw(data, port)
+* inl(port)
+* outl(port)
+* String operations
+* Pausing I/O
+* Platform Issues
+
+# Memory Region Allocation
+
+* request\\_mem\\_region(start, len, name)
+* release\\_mem\\_region(start, len)
+
+# Memory Mapping
+
+* ioremap(phys\\_addr, size)
+* iounmap(virt\\_addr)
+
+# Memory Access
+
+* ioread8(addr)
+* ioread16(addr)
+* ioread32(addr)
+* iowrite8(val, addr)
+* iowrite16(val, addr)
+* iowrite32(val, addr)
+* memset\\_io(addr, val, cnt)
+* memcpy\\_fromio(dst, src, cnt)
+* memcpy\\_toio(dst, src, cnt)
+
+# Mapping I/O Ports to Memory
+
+* ioport\\_map(port, cnt)
+* ioport\\_unmap(addr)
+
+# Memory Barries
+
+* linux/kernel.h
+* barrier()
+* asm/system.h
+* rmb()
+* wmb()
+* mb()
+* smp\\_rmb
+* smp\\_wmb
+* smp\\_mb