Hi Shanker,

On 06/06/16 06:40, Shanker Donthineni wrote:
> This patch adds the two handy helper functions for reading and writing
> ITS BASERn register.
> 
> Signed-off-by: Shanker Donthineni <shank...@codeaurora.org>
> ---
>  drivers/irqchip/irq-gic-v3-its.c | 32 +++++++++++++++++++++++++-------
>  1 file changed, 25 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-gic-v3-its.c 
> b/drivers/irqchip/irq-gic-v3-its.c
> index 5eb1f9e..6392c82 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -56,13 +56,14 @@ struct its_collection {
>  };
>  
>  /*
> - * The ITS_BASER structure - contains memory information and cached
> - * value of BASER register configuration.
> + * The ITS_BASER structure - contains memory information, cached value
> + * of BASER register configuration and register idx.
>   */
>  struct its_baser {
>       void            *base;
>       u64             val;
>       u32             order;
> +     u32             idx;
>  };
>  
>  /*
> @@ -824,6 +825,17 @@ static const char *its_base_type_string[] = {
>       [GITS_BASER_TYPE_RESERVED7]     = "Reserved (7)",
>  };
>  
> +static u64 its_read_baser(struct its_node *its, struct its_baser *baser)
> +{
> +     return readq_relaxed(its->base + GITS_BASER + (baser->idx << 3));
> +}
> +
> +static void its_write_baser(struct its_node *its, struct its_baser *baser,
> +                         u64 val)
> +{
> +     writeq_relaxed(val, its->base + GITS_BASER + (baser->idx << 3));
> +}
> +
>  static void its_free_tables(struct its_node *its)
>  {
>       int i;
> @@ -863,14 +875,20 @@ static int its_alloc_tables(const char *node_name, 
> struct its_node *its)
>       its->device_ids = ids;
>  
>       for (i = 0; i < GITS_BASER_NR_REGS; i++) {
> -             u64 val = readq_relaxed(its->base + GITS_BASER + i * 8);
> -             u64 type = GITS_BASER_TYPE(val);
> -             u64 entry_size = GITS_BASER_ENTRY_SIZE(val);
> +             struct its_baser *baser = its->tables + i;
>               int order = get_order(psz);
> +             u64 val, type, entry_size;
>               int alloc_pages;
>               u64 tmp;
>               void *base;
>  
> +             /* Record the register index */
> +             baser->idx = i;
> +
> +             val = its_read_baser(its, baser);
> +             type = GITS_BASER_TYPE(val);
> +             entry_size = GITS_BASER_ENTRY_SIZE(val);
> +
>               if (type == GITS_BASER_TYPE_NONE)
>                       continue;
>  
> @@ -939,8 +957,8 @@ retry_baser:
>               val |= alloc_pages - 1;
>               its->tables[i].val = val;
>  
> -             writeq_relaxed(val, its->base + GITS_BASER + i * 8);
> -             tmp = readq_relaxed(its->base + GITS_BASER + i * 8);
> +             its_write_baser(its, baser, val);
> +             tmp = its_read_baser(its, baser);
>  
>               if ((val ^ tmp) & GITS_BASER_SHAREABILITY_MASK) {
>                       /*
> 

It is worth realizing that we always end-up with baser being a pointer 
to one of the its->tables entries. We can easily simplify the whole 
thing and drop the idx field:

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 271c7f3..520d171 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -63,7 +63,6 @@ struct its_baser {
        void            *base;
        u64             val;
        u32             order;
-       u32             idx;
        u32             psz;
 };
 
@@ -828,13 +827,15 @@ static const char *its_base_type_string[] = {
 
 static u64 its_read_baser(struct its_node *its, struct its_baser *baser)
 {
-       return readq_relaxed(its->base + GITS_BASER + (baser->idx << 3));
+       int idx = baser - its->tables;
+       return readq_relaxed(its->base + GITS_BASER + (idx << 3));
 }
 
 static void its_write_baser(struct its_node *its, struct its_baser *baser,
                            u64 val)
 {
-       writeq_relaxed(val, its->base + GITS_BASER + (baser->idx << 3));
+       int idx = baser - its->tables;
+       writeq_relaxed(val, its->base + GITS_BASER + (idx << 3));
 }
 
 static int its_setup_baser(struct its_node *its, struct its_baser *baser,
@@ -1042,8 +1043,7 @@ static int its_alloc_tables(struct its_node *its)
                bool indirect = false;
                u64 type;
 
-               /* Record the register index and set preferred settings */
-               baser->idx = i;
+               /* Record the preferred settings */
                baser->val = cache | shr;
                baser->psz = psz;
 

Thanks,

        M.
-- 
Jazz is not dead. It just smells funny...

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