Re: [PATCH V5 7/7] acpi, gicv3, its: Use MADT ITS subtable to do PCI/MSI domain initialization.

[Tomasz Nowicki]

On 04.06.2016 14:07, Marc Zyngier wrote:

On Tue, 31 May 2016 13:19:44 +0200
Tomasz Nowicki <t...@semihalf.com> wrote:

Let ACPI build ITS PCI MSI domain. ACPI is responsible for retrieving
inner domain token and passing it on to its_pci_msi_init_one generic
init call.

We have now full PCI MSI domain stack, thus we can enable ITS initialization
from GICv3 core driver for ACPI scenario.

Signed-off-by: Tomasz Nowicki <t...@semihalf.com>
---
  drivers/irqchip/irq-gic-v3-its-pci-msi.c | 42 +++++++++++++++++++++++++++++++-
  drivers/irqchip/irq-gic-v3.c             |  3 +--
  2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its-pci-msi.c 
b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
index 23679ae..985f5d9 100644
--- a/drivers/irqchip/irq-gic-v3-its-pci-msi.c
+++ b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
@@ -15,6 +15,7 @@
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */

+#include <linux/iort.h>
  #include <linux/msi.h>
  #include <linux/of.h>
  #include <linux/of_irq.h>
@@ -144,10 +145,49 @@ static int __init its_pci_of_msi_init(void)
        return 0;
  }

+#ifdef CONFIG_ACPI
+
+static int __init
+its_pci_msi_parse_madt(struct acpi_subtable_header *header,
+                      const unsigned long end)
+{
+       struct acpi_madt_generic_translator *its_entry;
+       struct fwnode_handle *dom_handle;
+       char node_name[6 + 16 + 1]; // ITS identification name

Jeezus... Where is that coming from? Is that the size of "ITS@0x"+16
hex digits and a final NUL? For the sake of keeping things
maintainable/readable, please use kasprintf/kfree.

kasprintf/kfree will be used here.

+
+       its_entry = (struct acpi_madt_generic_translator *)header;
+       snprintf(node_name, 23, "ITS@0x%lx", (long)its_entry->base_address);
+       dom_handle = iort_its_find_domain_token(its_entry->translation_id);
+       if (!dom_handle) {
+               pr_err("%s: Unable to locate ITS domain handle\n", node_name);
+               return 0;

return 0? not even a slap on the wrist? Hum...

+       }
+
+       if (its_pci_msi_init_one(dom_handle, node_name))
+               return 0;

Same here.

Yeah, decent error code are needed here.

+
+       pr_info("PCI/MSI: %s domain created\n", node_name);
+       return 0;
+}
+
+static int __init its_pci_acpi_msi_init(void)
+{
+       acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
+                             its_pci_msi_parse_madt, 0);
+       return 0;
+}
+#else
+inline static int __init its_pci_acpi_msi_init(void)

static only.

OK

+{
+       return 0;
+}
+#endif
+
  static int __init its_pci_msi_init(void)
  {
        its_pci_of_msi_init();
+       its_pci_acpi_msi_init();
+
        return 0;
  }
-
  early_initcall(its_pci_msi_init);
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index cee8296..41c1cda 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -951,8 +951,7 @@ static int __init gic_init_bases(void __iomem *dist_base,

        set_handle_irq(gic_handle_irq);

-       if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis() &&
-           to_of_node(handle)) /* Temp hack to prevent ITS init for ACPI */
+       if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis())
                its_init(handle, &gic_data.rdists, gic_data.domain);

        gic_smp_init();

Thanks for review.

Tomasz