[PATCH v7 4/9] acpi/arm64: Add GTDT table parse driver

On Wed, Jul 13, 2016 at 7:53 PM,  [off-list ref] wrote:

This should depend on ARM64.

Also I wonder if it needs to be user-selectable?  Wouldn't it be
better to enable it by default when building for ARM64 with ACPI?

I would add "ACPI" to the prefix too if I were you, but that's me.

+
+typedef struct {
+       struct acpi_table_gtdt *gtdt;
+       void *platform_timer_start;
+       void *gtdt_end;
+} acpi_gtdt_desc_t;
+
+static acpi_gtdt_desc_t acpi_gtdt_desc __initdata;
+
+static inline void *next_platform_timer(void *platform_timer)
+{
+       struct acpi_gtdt_header *gh = platform_timer;
+
+       platform_timer += gh->length;
+       if (platform_timer < acpi_gtdt_desc.gtdt_end)
+               return platform_timer;
+
+       return NULL;
+}
+
+#define for_each_platform_timer(_g)                            \
+       for (_g = acpi_gtdt_desc.platform_timer_start; _g;      \
+            _g = next_platform_timer(_g))
+
+static inline bool is_timer_block(void *platform_timer)
+{
+       struct acpi_gtdt_header *gh = platform_timer;
+
+       if (gh->type == ACPI_GTDT_TYPE_TIMER_BLOCK)
+               return true;
+
+       return false;

This is just too much code.  It would suffice to do

    return gh->type == ACPI_GTDT_TYPE_TIMER_BLOCK;

+}
+
+static inline bool is_watchdog(void *platform_timer)
+{
+       struct acpi_gtdt_header *gh = platform_timer;
+
+       if (gh->type == ACPI_GTDT_TYPE_WATCHDOG)
+               return true;
+
+       return false;

Just like above.

+}
+
+/*
+ * Get some basic info from GTDT table, and init the global variables above
+ * for all timers initialization of Generic Timer.
+ * This function does some validation on GTDT table.
+ */
+static int __init acpi_gtdt_desc_init(struct acpi_table_header *table)
+{
+       struct acpi_table_gtdt *gtdt = container_of(table,
+                                                   struct acpi_table_gtdt,
+                                                   header);
+
+       acpi_gtdt_desc.gtdt = gtdt;
+       acpi_gtdt_desc.gtdt_end = (void *)table + table->length;
+
+       if (table->revision < 2) {
+               pr_info("Revision:%d doesn't support Platform Timers.\n",
+                       table->revision);

Is it really useful to print this message (and the one below) at the
"info" level?  What about changing them to pr_debug()?

+               return 0;
+       }
+
+       if (!gtdt->platform_timer_count) {
+               pr_info("No Platform Timer.\n");
+               return 0;
+       }
+
+       acpi_gtdt_desc.platform_timer_start = (void *)gtdt +
+                                             gtdt->platform_timer_offset;
+       if (acpi_gtdt_desc.platform_timer_start <
+           (void *)table + sizeof(struct acpi_table_gtdt)) {
+               pr_err(FW_BUG "Platform Timer pointer error.\n");

Why pr_err()?

+               acpi_gtdt_desc.platform_timer_start = NULL;
+               return -EINVAL;
+       }
+
+       return gtdt->platform_timer_count;
+}
+
+static int __init map_generic_timer_interrupt(u32 interrupt, u32 flags)
+{
+       int trigger, polarity;
+
+       if (!interrupt)
+               return 0;
+
+       trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
+                       : ACPI_LEVEL_SENSITIVE;
+
+       polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
+                       : ACPI_ACTIVE_HIGH;
+
+       return acpi_register_gsi(NULL, interrupt, trigger, polarity);
+}
+
+/*
+ * Map the PPIs of per-cpu arch_timer.
+ * @type: the type of PPI
+ * Returns 0 if error.
+ */
+int __init acpi_gtdt_map_ppi(int type)
+{
+       struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
+
+       switch (type) {
+       case PHYS_SECURE_PPI:
+               return map_generic_timer_interrupt(gtdt->secure_el1_interrupt,
+                                                  gtdt->secure_el1_flags);
+       case PHYS_NONSECURE_PPI:
+               return map_generic_timer_interrupt(gtdt->non_secure_el1_interrupt,
+                                                  gtdt->non_secure_el1_flags);
+       case VIRT_PPI:
+               return map_generic_timer_interrupt(gtdt->virtual_timer_interrupt,
+                                                  gtdt->virtual_timer_flags);
+
+       case HYP_PPI:
+               return map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt,
+                                                  gtdt->non_secure_el2_flags);
+       default:
+               pr_err("ppi type error.\n");
+       }
+
+       return 0;
+}
+
+/*
+ * acpi_gtdt_c3stop - got c3stop info from GTDT
+ *
+ * Returns 1 if the timer is powered in deep idle state, 0 otherwise.
+ */
+int __init acpi_gtdt_c3stop(void)

Why not bool?

+{
+       struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
+
+       return !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
+}
+
+int __init gtdt_arch_timer_init(struct acpi_table_header *table)
+{
+       if (table)
+               return acpi_gtdt_desc_init(table);
+
+       pr_err("table pointer error.\n");

This message is totally unuseful.

+
+       return -EINVAL;
+}

What is supposed to be calling this function?

The __init thing is not necessary here.

+#endif
+
 #else  /* !CONFIG_ACPI */

 #define acpi_disabled 1
--

Thanks,
Rafael