On 03/03/2012 11:35 AM, Rob Herring wrote:

On 03/02/2012 01:29 PM, David Daney wrote:

quoted

On 03/02/2012 11:07 AM, Grant Likely wrote:

quoted

+static void __init octeon_irq_set_ciu_mapping(unsigned int irq,
+                          unsigned int line,
+                          unsigned int bit,
+                          struct irq_domain *domain,
                              struct irq_chip *chip,
                              irq_flow_handler_t handler)
    {
+    struct irq_data *irqd;
        union octeon_ciu_chip_data cd;

        irq_set_chip_and_handler(irq, chip, handler);
-
        cd.l = 0;
        cd.s.line = line;
        cd.s.bit = bit;

        irq_set_chip_data(irq, cd.p);
        octeon_irq_ciu_to_irq[line][bit] = irq;
+
+    irqd = irq_get_irq_data(irq);
+    irqd->hwirq = line<<    6 | bit;
+    irqd->domain = domain;

quoted

quoted

I think the domain code will set these.

It is my understanding that the domain code only does this for:

o irq_domain_add_legacy()

o irq_create_direct_mapping()

o irq_create_mapping()

We use none of those.  So I do it here.

If there is a better way, I am open to suggestions.

irq_create_mapping is called by irq_create_of_mapping() which is
in turn called by irq_of_parse_and-map().  irq_domain always
manages the hwirq and domain values.  Driver code cannot manipulate
them manually.

I really must be missing something.

Given:

1) I must have a mapping between hwirq and irq that I control so that
non-OF code using the OCTEON_IRQ_* constants continues to work.

Those defines are what you need to work to get rid of.

We are not starting from a blank slate here.  There is a lot of in-tree 
code using these symbols.  We cannot make them disappear with wishful 
thinking.

The first step is a switch to irq_domains using the existing mappings.

After we do that, I have patches to transition some drivers to use the 
OF mapping via irq_domains.  After those are merged, we can work toward 
getting rid of OCTEON_IRQ_*.  But I think it must be the last step in 
the process, not the first.

quoted

2) irq_create_mapping() will allocate a random irq value if none is
already assigned to the hwirq.

Therefore: To avoid having random irq values assigned, I must manually
assign them.

So you should be using legacy domain if you need to maintain fixed hwirq
to linux irq numbers. "linear" is a bit confusing as it doesn't mean
linear 1:1 irq number assignment, but linear search.

My reading of Grant's code in linux-next directly contradicts this 
statement.  There is no code in irqdomain.c, that I can see, that allows 
me to have an arbitrary mapping of irq <--> hwirq values.

Ultimately, for DT boot you should use of_irq_init to scan the dts, and
then create a linear domain for each interrupt controller node. You may
need to decide on linear vs. legacy at runtime based on having a DT node
pointer or not.

Perhaps, but we need to take the first step before gradually arriving at 
some Ultimate Solution.

We will also need to handle irq controllers with 2^20 sparsely populated 
hwirq values, so linear domains will probably be out of the question there.

David Daney