2009/2/26 Venkatesh Rao <venkateshnrao@xxxxxxxxx>:
> i have written a kernel module for my 2.6.23.1 patched with rtai
>
> the file is as follows:
>
> #include <linux/module.h>
> #include <linux/kernel.h>
> #include <linux/init.h>
> #include <linux/stddef.h>
> #include <linux/ioport.h>
> #include <linux/types.h>
> #include <asm/io.h>
> #include <rtai.h>
> #include <rtai_sched.h>
> #include <rtai_fifos.h>
>
>
>
> #define FIFO 0
> #define SERPORT 0x3f8
>
>
>
>
>
>
> static void handler()
> {
> int y,i=1;
> rt_printk("\n interrupted now \n");
> for(;i<=14; i++)
> {
> y=inb(SERPORT);
> rtf_put(FIFO, &y, sizeof(y));
> rt_printk("%d ",y);
> }
> rt_ack_irq(4);
> }
>
>
> int init_module(void)
> {
>
> rt_printk("...................................start..................................\n\n");
> int ret;
> rt_free_global_irq(4); // freeing this first may not need to do this
> rt_printk("\nmodule inserted\n");
> ret = rt_request_global_irq(4, (void *)handler);
> if (ret) { printk ("\n\n##### error requesting irq 4: returned %d\n",
> ret); }
> rt_enable_irq(4);
>
> outb_p(0x83, SERPORT + 3); // set DLAB
> outb_p(0x0c, SERPORT); // set baud rate to 9600
> outb_p(0x00, SERPORT+1);
>
> outb_p(((0x83)&(0x7f)), SERPORT + 3); //reset DLAB
>
> outb_p(0x05,SERPORT + 1); //enable serial port interrupt
>
> outb_p(0x07,SERPORT + 2); // fifo control register enable fifos, clear
> rx & tx fifo, set intr. trigger to 14 bytes
>
> rt_set_oneshot_mode();
>
> rtf_create(FIFO,1024);
>
> rt_printk("\ntimer started\n");
>
> rt_printk("\n interrupt indentification register %x \n", inb(SERPORT +
> 2));
>
> start_rt_timer(1);
>
> }
>
> void cleanup_module(void)
> {
> stop_rt_timer();
> rtf_destroy(FIFO);
> rt_free_global_irq(4);
> printk("\nReal Time Task Destroyed");
> printk("\nModule cleanup");
> }
>
> MODULE_LICENSE("GPL");
>
>
> the dmesg output shows:
>
> module inserted
>
> timer started
>
> (IIR) interrupt indentification register c1
>
> contents of IIR register indicates that fifos ARE ENABLED.....
>
>
>
>
> however when i send data from my atmega 8535 board at a baud rate of 9600,
> no interrupts are generated the control never goes to the handler.
>
> outputs of files in /proc directory:
>
> interrupts:\
>
> CPU0 CPU1
> 0: 254 0 IO-APIC-edge timer
> 1: 2258 0 IO-APIC-edge i8042
> 7: 1 0 IO-APIC-edge parport0
> 8: 1 0 IO-APIC-edge rtc
> 9: 1 0 IO-APIC-fasteoi acpi
> 12: 28074 0 IO-APIC-edge i8042
> 14: 16336 0 IO-APIC-edge libata
> 15: 8780 0 IO-APIC-edge libata
> 16: 1954 0 IO-APIC-fasteoi ehci_hcd:usb1, uhci_hcd:usb2
> 17: 0 0 IO-APIC-fasteoi uhci_hcd:usb3
> 18: 0 0 IO-APIC-fasteoi uhci_hcd:usb4
> 19: 301 0 IO-APIC-fasteoi uhci_hcd:usb5, HDA Intel,
> i915@pci:0000:00:02.0
> 20: 25787 0 IO-APIC-fasteoi eth0
> NMI: 0 0
> LOC: 546731 586187
> ERR: 0
> MIS: 0
> ~
>
>
> ioports:
> 0000-001f : dma1
> 0020-0021 : pic1
> 0040-0043 : timer0
> 0050-0053 : timer1
> 0060-006f : keyboard
> 0070-0077 : rtc
> 0080-008f : dma page reg
> 00a0-00a1 : pic2
> 00c0-00df : dma2
> 00f0-00ff : fpu
> 0170-0177 : 0000:00:1f.2
> 0170-0177 : libata
> 01f0-01f7 : 0000:00:1f.2
> 01f0-01f7 : libata
> 02f8-02ff : serial
> 0376-0376 : 0000:00:1f.2
> 0376-0376 : libata
> 0378-037a : parport0
> 03c0-03df : vga+
> 03f6-03f6 : 0000:00:1f.2
> 03f6-03f6 : libata
> 03f8-03ff : serial
> 0400-047f : 0000:00:1f.0
> 0400-0403 : ACPI PM1a_EVT_BLK
> 0404-0405 : ACPI PM1a_CNT_BLK
> 0408-040b : ACPI PM_TMR
> 0410-0415 : ACPI CPU throttle
> 0428-042f : ACPI GPE0_BLK
> 0460-047f : iTCO_wdt
> 0480-04bf : 0000:00:1f.0
> 0500-051f : 0000:00:1f.3
> 0500-051f : i801_smbus
> 0cf8-0cff : PCI conf1
> a000-afff : PCI Bus #01
> a000-a0ff : 0000:01:05.0
> a000-a0ff : skge
> b000-b01f : 0000:00:1d.0
> b000-b01f : uhci_hcd
> b400-b41f : 0000:00:1d.1
> b400-b41f : uhci_hcd
> b800-b81f : 0000:00:1d.2
> b800-b81f : uhci_hcd
> bc00-bc1f : 0000:00:1d.3
> bc00-bc1f : uhci_hcd
>
>
> i see that there is no line in the interrupts file for serial port.
>
> however when i do setserial /dev/ttyS0 i get
>
> [root@localhost proc]# setserial /dev/ttyS0
> /dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4
>
>
> why is the interrupt not being generated kindly guide me....
>
I think you need to unload the serial driver first and only then load
yours, so it can control your serial port.
--
Denis
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