Commit 72cac213 authored by Michael Ellerman's avatar Michael Ellerman Committed by Paul Mackerras
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[POWERPC] Add debugging trigger to Axon MSI code 



This adds some debugging code to the Axon MSI driver.  It creates a
file per MSIC in /sys/kernel/debug/powerpc, which allows the user to
trigger a fake MSI interrupt by writing to the file.

This can be used to test some of the MSI generation path.  In
particular, that the MSIC recognises a write to the MSI address,
generates an interrupt and writes the MSI packet into the ring buffer.

All the code is inside #ifdef DEBUG so it causes no harm unless it's
enabled.

Signed-off-by: default avatarMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 475ca391

arch/powerpc/platforms/cell/axon_msi.c

+58 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/pci.h>

#include <linux/msi.h>

#include <linux/of_platform.h>

#include <linux/debugfs.h>



#include <asm/dcr.h>

#include <asm/machdep.h>
@@ -69,8 +70,19 @@ struct axon_msic { 
	dma_addr_t fifo_phys;

	dcr_host_t dcr_host;

	u32 read_offset;

#ifdef DEBUG

	u32 __iomem *trigger;

#endif

};



#ifdef DEBUG

void axon_msi_debug_setup(struct device_node *dn, struct axon_msic *msic);

#else

static inline void axon_msi_debug_setup(struct device_node *dn,

					struct axon_msic *msic) { }

#endif





static void msic_dcr_write(struct axon_msic *msic, unsigned int dcr_n, u32 val)

{

	pr_debug("axon_msi: dcr_write(0x%x, 0x%x)\n", val, dcr_n);
@@ -381,6 +393,8 @@ static int axon_msi_probe(struct of_device *device, 
	ppc_md.teardown_msi_irqs = axon_msi_teardown_msi_irqs;

	ppc_md.msi_check_device = axon_msi_check_device;



	axon_msi_debug_setup(dn, msic);



	printk(KERN_DEBUG "axon_msi: setup MSIC on %s\n", dn->full_name);



	return 0;
@@ -418,3 +432,47 @@ static int __init axon_msi_init(void) 
	return of_register_platform_driver(&axon_msi_driver);

}

subsys_initcall(axon_msi_init);





#ifdef DEBUG

static int msic_set(void *data, u64 val)

{

	struct axon_msic *msic = data;

	out_le32(msic->trigger, val);

	return 0;

}



static int msic_get(void *data, u64 *val)

{

	*val = 0;

	return 0;

}



DEFINE_SIMPLE_ATTRIBUTE(fops_msic, msic_get, msic_set, "%llu\n");



void axon_msi_debug_setup(struct device_node *dn, struct axon_msic *msic)

{

	char name[8];

	u64 addr;



	addr = of_translate_address(dn, of_get_property(dn, "reg", NULL));

	if (addr == OF_BAD_ADDR) {

		pr_debug("axon_msi: couldn't translate reg property\n");

		return;

	}



	msic->trigger = ioremap(addr, 0x4);

	if (!msic->trigger) {

		pr_debug("axon_msi: ioremap failed\n");

		return;

	}



	snprintf(name, sizeof(name), "msic_%d", of_node_to_nid(dn));



	if (!debugfs_create_file(name, 0600, powerpc_debugfs_root,

				 msic, &fops_msic)) {

		pr_debug("axon_msi: debugfs_create_file failed!\n");

		return;

	}

}

#endif /* DEBUG */

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