Problem in using external interrupt in MPC 8323 RDB

gangadharrao — Mon, 17 Apr 2017 11:00:23 GMT

we are using MPC 8323 RDB board and loaded with Linux 2.6. Can anyone please verify the attached code and suggest what is going wrong with the code.

Original Attachment has been moved to: led_mod.c.zip

Re: Problem in using external interrupt in MPC 8323 RDB

Pavel — Thu, 20 Apr 2017 06:08:31 GMT

I can see the following interrupts on the MPC8323RDB board:

~ # cat /proc/interrupts

CPU0

16: 165 IPIC Level serial

18: 0 IPIC Level i2c-mpc

19: 0 IPIC Level ehci_hcd:usb1, ohci_hcd:usb2

20: 13837 QEIC Level tdm

21: 0 QEIC Level UCC Geth

22: 0 QEIC Level mpc83xx_spi

34: 0 QEIC Level UCC Geth

Look at recommendations below for the MPC823x_RDB LTIB Linux BSP.

Linux makes no difference between external and internal interrupts. All interrupts in the system are handled by the same Linux API. If this API didn't work, no driver in the system would be able to operate, not just your customer's module.

The customer is attempting to request an IRQ by the resource number which is generally incorrect. The resource number is an index to irq_desc table.

This index is generally _not_equal to the hardware IRQ line number. See Documentation/IRQ.txt for explanation.

To request an IRQ line in a proper way, the customer should:

Declare the IRQ properly in the DTS. Refer to /Documentation/powerpc/booting-without-of.txt for details. The value of the "interrupt"

property is calculated by the following

formula:

[DTS_interrupt_number] = ([EIVPR/IIVPR_addr] - [Interrupt_Source_Configuration_Registers_Base]) / 0x20

where [EIVPR/IIVPR_addr] is the address of the interrupt configuration registers

of the IRQ being declared, [Interrupt_Source_Configuration_Registers_Base]

is 0x50000 for P1010

Request the interrupt property from the Open Firmware in the driver.

Map the interrupt to the resource ID. This can be done by of_irq_to_resource() or by irq_of_parse_and_map().

Request the interrupt by the resource number.

All steps above are performed by _any_ device driver in the system. Just look how it is done in e.g. drivers/net/gianfar.c or drivers/spi/fsl_espi.c

and do the same in your code.

Look at also attached file. It is common method for interrupt handling under Linux.

Check your code using this document.

Have a great day,
Pavel Chubakov

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Problem in using external interrupt in MPC 8323 RDB

Re: Problem in using external interrupt in MPC 8323 RDB