Re: [PATCH] CONFIG_GENERIC_ISA_DMA (for testing)

[Russell King <rmk@arm.linux.org.uk>]

Here's an updated version, taking into account hch's and David Mosburger's
comments.  It's against 2.5.20.  I've checked that (after some messing
about) it builds under ARM, but it needs someone to make sure that
"cat /proc/dma" produces the expected output.

--- orig/arch/alpha/config.in	Wed May 29 23:56:58 2002
+++ linux/arch/alpha/config.in	Wed May 29 21:55:08 2002
@@ -7,6 +7,7 @@
 define_bool CONFIG_UID16 n
 define_bool CONFIG_RWSEM_GENERIC_SPINLOCK n
 define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM y
+define_bool CONFIG_GENERIC_ISA_DMA y
 
 source init/Config.in
 
--- orig/arch/i386/config.in	Wed Jun  5 10:08:22 2002
+++ linux/arch/i386/config.in	Sat May 25 10:25:43 2002
@@ -9,6 +9,7 @@
 define_bool CONFIG_SBUS n
 
 define_bool CONFIG_UID16 y
+define_bool CONFIG_GENERIC_ISA_DMA y
 
 source init/Config.in
 
--- orig/arch/m68k/config.in	Sat May 25 11:09:21 2002
+++ linux/arch/m68k/config.in	Mon May 13 10:16:01 2002
@@ -6,6 +6,7 @@
 define_bool CONFIG_UID16 y
 define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
 define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
+define_bool CONFIG_GENERIC_ISA_DMA y
 
 mainmenu_name "Linux/68k Kernel Configuration"
 
--- orig/arch/mips/config.in	Sat May 25 11:09:28 2002
+++ linux/arch/mips/config.in	Wed Apr 24 19:32:40 2002
@@ -4,6 +4,7 @@
 #
 define_bool CONFIG_MIPS y
 define_bool CONFIG_SMP n
+define_bool CONFIG_GENERIC_ISA_DMA y
 
 mainmenu_name "Linux Kernel Configuration"
 
--- orig/arch/mips64/config.in	Sat May 25 11:09:34 2002
+++ linux/arch/mips64/config.in	Wed Apr 24 19:32:40 2002
@@ -26,6 +26,7 @@
 
 define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
 define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
+define_bool CONFIG_GENERIC_ISA_DMA y
 
 #
 # Select some configuration options automatically based on user selections
--- orig/arch/parisc/config.in	Sat May 25 11:09:39 2002
+++ linux/arch/parisc/config.in	Sun Feb 24 16:46:01 2002
@@ -9,6 +9,7 @@
 define_bool CONFIG_UID16 n
 define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
 define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
+define_bool CONFIG_GENERIC_ISA_DMA y
 
 source init/Config.in
 
--- orig/arch/ppc/config.in	Wed May 29 23:57:00 2002
+++ linux/arch/ppc/config.in	Wed May 29 21:55:14 2002
@@ -7,6 +7,7 @@
 define_bool CONFIG_RWSEM_GENERIC_SPINLOCK n
 define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM y
 define_bool CONFIG_HAVE_DEC_LOCK y
+define_bool CONFIG_GENERIC_ISA_DMA y
 
 mainmenu_name "Linux/PowerPC Kernel Configuration"
 
--- orig/arch/sh/config.in	Sat May 25 11:09:56 2002
+++ linux/arch/sh/config.in	Sat Mar 23 23:09:17 2002
@@ -9,6 +9,7 @@
 define_bool CONFIG_UID16 y
 define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
 define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
+define_bool CONFIG_GENERIC_ISA_DMA y
 
 source init/Config.in
 
--- orig/arch/sparc/config.in	Sat May 25 11:09:59 2002
+++ linux/arch/sparc/config.in	Fri May  3 10:39:16 2002
@@ -6,6 +6,7 @@
 
 define_bool CONFIG_UID16 y
 define_bool CONFIG_HIGHMEM y
+define_bool CONFIG_GENERIC_ISA_DMA y
 
 source init/Config.in
 
--- orig/arch/sparc64/config.in	Sat May 25 11:10:04 2002
+++ linux/arch/sparc64/config.in	Mon May  6 16:42:10 2002
@@ -26,6 +26,7 @@
 define_bool CONFIG_HAVE_DEC_LOCK y
 define_bool CONFIG_RWSEM_GENERIC_SPINLOCK n
 define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM y
+define_bool CONFIG_GENERIC_ISA_DMA y
 define_bool CONFIG_ISA n
 define_bool CONFIG_ISAPNP n
 define_bool CONFIG_EISA n
--- linux-tolinus/kernel/Makefile	Wed Jun  5 10:08:25 2002
+++ linux/kernel/Makefile	Wed Jun  5 18:38:14 2002
@@ -10,13 +10,14 @@
 O_TARGET := kernel.o
 
 export-objs = signal.o sys.o kmod.o context.o ksyms.o pm.o exec_domain.o \
-		printk.o platform.o suspend.o
+	      printk.o platform.o suspend.o dma.o
 
-obj-y     = sched.o dma.o fork.o exec_domain.o panic.o printk.o \
+obj-y     = sched.o fork.o exec_domain.o panic.o printk.o \
 	    module.o exit.o itimer.o info.o time.o softirq.o resource.o \
 	    sysctl.o capability.o ptrace.o timer.o user.o \
 	    signal.o sys.o kmod.o context.o futex.o platform.o
 
+obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
 obj-$(CONFIG_UID16) += uid16.o
 obj-$(CONFIG_MODULES) += ksyms.o
 obj-$(CONFIG_PM) += pm.o
--- linux-tolinus/kernel/dma.c	Sat May 25 11:13:57 2002
+++ linux/kernel/dma.c	Wed Jun  5 19:26:12 2002
@@ -9,11 +9,14 @@
  *   [It also happened to remove the sizeof(char *) == sizeof(int)
  *   assumption introduced because of those /proc/dma patches. -- Hennus]
  */
-
+#include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/spinlock.h>
 #include <linux/string.h>
+#include <linux/seq_file.h>
+#include <linux/proc_fs.h>
+#include <linux/init.h>
 #include <asm/dma.h>
 #include <asm/system.h>
 
@@ -65,20 +68,6 @@
 	{ 0, 0 }
 };
 
-int get_dma_list(char *buf)
-{
-	int i, len = 0;
-
-	for (i = 0 ; i < MAX_DMA_CHANNELS ; i++) {
-		if (dma_chan_busy[i].lock) {
-		    len += sprintf(buf+len, "%2d: %s\n",
-				   i,
-				   dma_chan_busy[i].device_id);
-		}
-	}
-	return len;
-} /* get_dma_list */
-
 
 int request_dma(unsigned int dmanr, const char * device_id)
 {
@@ -109,6 +98,19 @@
 
 } /* free_dma */
 
+static int proc_dma_show(struct seq_file *m, void *v)
+{
+	int i;
+
+	for (i = 0 ; i < MAX_DMA_CHANNELS ; i++) {
+		if (dma_chan_busy[i].lock) {
+		    seq_printf(m, "%2d: %s\n", i,
+			       dma_chan_busy[i].device_id);
+		}
+	}
+	return 0;
+}
+
 #else
 
 int request_dma(unsigned int dmanr, const char *device_id)
@@ -120,9 +122,52 @@
 {
 }
 
-int get_dma_list(char *buf)
-{	
-	strcpy(buf, "No DMA\n");
-	return 7;
+static int proc_dma_show(struct seq_file *m, void *v)
+{
+	seq_puts(m, "No DMA\n");
+	return 0;
 }
+
 #endif
+
+static int proc_dma_open(struct inode *inode, struct file *file)
+{
+	char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	struct seq_file *m;
+	int res;
+
+	if (!buf)
+		return -ENOMEM;
+	res = single_open(file, proc_dma_show, NULL);
+	if (!res) {
+		m = file->private_data;
+		m->buf = buf;
+		m->size = PAGE_SIZE;
+	} else
+		kfree(buf);
+	return res;
+}
+
+static struct file_operations proc_dma_operations = {
+	open:		proc_dma_open,
+	read:		seq_read,
+	llseek:		seq_lseek,
+	release:	single_release,
+};
+
+static int __init proc_dma_init(void)
+{
+	struct proc_dir_entry *e;
+
+	e = create_proc_entry("dma", 0, NULL);
+	if (e)
+		e->proc_fops = &proc_dma_operations;
+
+	return 0;
+}
+
+__initcall(proc_dma_init);
+
+EXPORT_SYMBOL(request_dma);
+EXPORT_SYMBOL(free_dma);
+EXPORT_SYMBOL(dma_spin_lock);
--- linux-tolinus/kernel/ksyms.c	Wed Jun  5 10:08:25 2002
+++ linux/kernel/ksyms.c	Wed Jun  5 18:48:44 2002
@@ -63,9 +63,6 @@
 extern void *sys_call_table;
 
 extern struct timezone sys_tz;
-extern int request_dma(unsigned int dmanr, const char * deviceID);
-extern void free_dma(unsigned int dmanr);
-extern spinlock_t dma_spin_lock;
 
 #ifdef CONFIG_MODVERSIONS
 const struct module_symbol __export_Using_Versions
@@ -435,10 +433,6 @@
 EXPORT_SYMBOL(brw_kiovec);
 EXPORT_SYMBOL(kiobuf_wait_for_io);
 
-/* dma handling */
-EXPORT_SYMBOL(request_dma);
-EXPORT_SYMBOL(free_dma);
-EXPORT_SYMBOL(dma_spin_lock);
 #ifdef HAVE_DISABLE_HLT
 EXPORT_SYMBOL(disable_hlt);
 EXPORT_SYMBOL(enable_hlt);
--- linux-tolinus/fs/proc/proc_misc.c	Wed May 29 23:57:09 2002
+++ linux/fs/proc/proc_misc.c	Wed Jun  5 19:17:51 2002
@@ -394,13 +394,6 @@
 	return proc_calc_metrics(page, start, off, count, eof, len);
 }
 
-static int dma_read_proc(char *page, char **start, off_t off,
-				 int count, int *eof, void *data)
-{
-	int len = get_dma_list(page);
-	return proc_calc_metrics(page, start, off, count, eof, len);
-}
-
 static int ioports_read_proc(char *page, char **start, off_t off,
 				 int count, int *eof, void *data)
 {
@@ -553,7 +546,6 @@
 		{"stat",	kstat_read_proc},
 		{"devices",	devices_read_proc},
 		{"filesystems",	filesystems_read_proc},
-		{"dma",		dma_read_proc},
 		{"ioports",	ioports_read_proc},
 		{"cmdline",	cmdline_read_proc},
 #ifdef CONFIG_SGI_DS1286

-- 
Russell King (rmk@arm.linux.org.uk)                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html