The PPC476GTR SoC supports message signalled interrupts (MSI) by writing
to special addresses within the High Speed Transfer Assist (HSTA) module.

This patch adds support for PCI MSI with a new system device. The DMA
window is also updated to allow access to the entire 42-bit address range
to allow PCI devices write access to the HSTA module.

Signed-off-by: Alistair Popple <alist...@popple.id.au>
---
 .../devicetree/bindings/powerpc/4xx/hsta.txt       |  19 ++
 arch/powerpc/boot/dts/akebono.dts                  |  46 ++++-
 arch/powerpc/boot/treeboot-akebono.c               |  15 --
 arch/powerpc/platforms/44x/Kconfig                 |   2 +
 arch/powerpc/sysdev/Kconfig                        |   6 +
 arch/powerpc/sysdev/Makefile                       |   1 +
 arch/powerpc/sysdev/ppc4xx_hsta_msi.c              | 215 +++++++++++++++++++++
 arch/powerpc/sysdev/ppc4xx_pci.c                   |   8 +-
 8 files changed, 287 insertions(+), 25 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/powerpc/4xx/hsta.txt
 create mode 100644 arch/powerpc/sysdev/ppc4xx_hsta_msi.c

diff --git a/Documentation/devicetree/bindings/powerpc/4xx/hsta.txt 
b/Documentation/devicetree/bindings/powerpc/4xx/hsta.txt
new file mode 100644
index 0000000..c737c83
--- /dev/null
+++ b/Documentation/devicetree/bindings/powerpc/4xx/hsta.txt
@@ -0,0 +1,19 @@
+
+ppc476gtr High Speed Serial Assist (HSTA) node
+==============================================
+
+The 476gtr SoC contains a high speed serial assist module attached
+between the plb4 and plb6 system buses to provide high speed data
+transfer between memory and system peripherals as well as support for
+PCI message signalled interrupts.
+
+Currently only the MSI support is used by Linux using the following
+device tree entries:
+
+Require properties:
+- compatible           : "ibm,476gtr-hsta-msi", "ibm,hsta-msi"
+- reg                  : register mapping for the HSTA MSI space
+- interrupt-parent     : parent controller for mapping interrupts
+- interrupts           : ordered interrupt mapping for each MSI in the register
+                         space. The first interrupt should be associated with a
+                         register offset of 0x00, the second to 0x10, etc.
diff --git a/arch/powerpc/boot/dts/akebono.dts 
b/arch/powerpc/boot/dts/akebono.dts
index 96ac13b..f92ecfe 100644
--- a/arch/powerpc/boot/dts/akebono.dts
+++ b/arch/powerpc/boot/dts/akebono.dts
@@ -82,6 +82,28 @@
                ranges;
                clock-frequency = <200000000>; // 200Mhz
 
+               HSTA0: hsta@310000e0000 {
+                       compatible = "ibm,476gtr-hsta-msi", "ibm,hsta-msi";
+                       reg = <0x310 0x000e0000 0x0 0xf0>;
+                       interrupt-parent = <&MPIC>;
+                       interrupts = <108 0
+                                     109 0
+                                     110 0
+                                     111 0
+                                     112 0
+                                     113 0
+                                     114 0
+                                     115 0
+                                     116 0
+                                     117 0
+                                     118 0
+                                     119 0
+                                     120 0
+                                     121 0
+                                     122 0
+                                     123 0>;
+               };
+
                MAL0: mcmal {
                        compatible = "ibm,mcmal-476gtr", "ibm,mcmal2";
                        dcr-reg = <0xc0000000 0x062>;
@@ -242,8 +264,10 @@
                        ranges = <0x02000000 0x00000000 0x80000000 0x00000110 
0x80000000 0x0 0x80000000
                                  0x01000000 0x0        0x0        0x00000140 
0x0        0x0 0x00010000>;
 
-                       /* Inbound starting at 0 to memsize filled in by zImage 
*/
-                       dma-ranges = <0x42000000 0x0 0x0 0x0 0x0 0x0 0x0>;
+                       /* Inbound starting at 0x0 to 0x40000000000. In order 
to use MSI
+                        * PCI devices must be able to write to the HSTA module.
+                        */
+                       dma-ranges = <0x42000000 0x0 0x0 0x0 0x0 0x400 0x0>;
 
                        /* This drives busses 0 to 0xf */
                        bus-range = <0x0 0xf>;
@@ -280,8 +304,10 @@
                        ranges = <0x02000000 0x00000000 0x80000000 0x00000210 
0x80000000 0x0 0x80000000
                                  0x01000000 0x0        0x0        0x00000240 
0x0        0x0 0x00010000>;
 
-                       /* Inbound starting at 0 to memsize filled in by zImage 
*/
-                       dma-ranges = <0x42000000 0x0 0x0 0x0 0x0 0x0 0x0>;
+                       /* Inbound starting at 0x0 to 0x40000000000. In order 
to use MSI
+                        * PCI devices must be able to write to the HSTA module.
+                        */
+                       dma-ranges = <0x42000000 0x0 0x0 0x0 0x0 0x400 0x0>;
 
                        /* This drives busses 0 to 0xf */
                        bus-range = <0x0 0xf>;
@@ -318,8 +344,10 @@
                        ranges = <0x02000000 0x00000000 0x80000000 0x00000190 
0x80000000 0x0 0x80000000
                                  0x01000000 0x0        0x0        0x000001c0 
0x0        0x0 0x00010000>;
 
-                       /* Inbound starting at 0 to memsize filled in by zImage 
*/
-                       dma-ranges = <0x42000000 0x0 0x0 0x0 0x0 0x0 0x0>;
+                       /* Inbound starting at 0x0 to 0x40000000000. In order 
to use MSI
+                        * PCI devices must be able to write to the HSTA module.
+                        */
+                       dma-ranges = <0x42000000 0x0 0x0 0x0 0x0 0x400 0x0>;
 
                        /* This drives busses 0 to 0xf */
                        bus-range = <0x0 0xf>;
@@ -356,8 +384,10 @@
                        ranges = <0x02000000 0x00000000 0x80000000 0x00000290 
0x80000000 0x0 0x80000000
                                  0x01000000 0x0        0x0        0x000002c0 
0x0        0x0 0x00010000>;
 
-                       /* Inbound starting at 0 to memsize filled in by zImage 
*/
-                       dma-ranges = <0x42000000 0x0 0x0 0x0 0x0 0x0 0x0>;
+                       /* Inbound starting at 0x0 to 0x40000000000. In order 
to use MSI
+                        * PCI devices must be able to write to the HSTA module.
+                        */
+                       dma-ranges = <0x42000000 0x0 0x0 0x0 0x0 0x400 0x0>;
 
                        /* This drives busses 0 to 0xf */
                        bus-range = <0x0 0xf>;
diff --git a/arch/powerpc/boot/treeboot-akebono.c 
b/arch/powerpc/boot/treeboot-akebono.c
index 070a20f..b73174c 100644
--- a/arch/powerpc/boot/treeboot-akebono.c
+++ b/arch/powerpc/boot/treeboot-akebono.c
@@ -75,24 +75,9 @@ static void ibm_akebono_fixups(void)
 {
        void *emac;
        u32 reg;
-       void *devp = finddevice("/");
-       u32 dma_ranges[7];
 
        dt_fixup_memory(0x0ULL,  ibm_akebono_memsize);
 
-       while ((devp = find_node_by_devtype(devp, "pci"))) {
-               if (getprop(devp, "dma-ranges", dma_ranges,
-                           sizeof(dma_ranges)) < 0) {
-                       printf("%s: Failed to get dma-ranges\r\n", __func__);
-                       continue;
-               }
-
-               dma_ranges[5] = ibm_akebono_memsize >> 32;
-               dma_ranges[6] = ibm_akebono_memsize & 0xffffffffUL;
-
-               setprop(devp, "dma-ranges", dma_ranges, sizeof(dma_ranges));
-       }
-
        /* Fixup the SD timeout frequency */
        mtdcrx(CCTL0_MCO4, 0x1);
 
diff --git a/arch/powerpc/platforms/44x/Kconfig 
b/arch/powerpc/platforms/44x/Kconfig
index b0202d8..8beec7d 100644
--- a/arch/powerpc/platforms/44x/Kconfig
+++ b/arch/powerpc/platforms/44x/Kconfig
@@ -206,6 +206,8 @@ config AKEBONO
        select SWIOTLB
        select 476FPE
        select PPC4xx_PCI_EXPRESS
+       select PCI_MSI
+       select PPC4xx_HSTA_MSI
        select I2C
        select I2C_IBM_IIC
        select NETDEVICES
diff --git a/arch/powerpc/sysdev/Kconfig b/arch/powerpc/sysdev/Kconfig
index 7baa70d..a19332a 100644
--- a/arch/powerpc/sysdev/Kconfig
+++ b/arch/powerpc/sysdev/Kconfig
@@ -7,6 +7,12 @@ config PPC4xx_PCI_EXPRESS
        depends on PCI && 4xx
        default n
 
+config PPC4xx_HSTA_MSI
+       bool
+       depends on PCI_MSI
+       depends on PCI && 4xx
+       default n
+
 config PPC4xx_MSI
        bool
        depends on PCI_MSI
diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index afbcc37..f7cb2a1 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -45,6 +45,7 @@ obj-$(CONFIG_OF_RTC)          += of_rtc.o
 ifeq ($(CONFIG_PCI),y)
 obj-$(CONFIG_4xx)              += ppc4xx_pci.o
 endif
+obj-$(CONFIG_PPC4xx_HSTA_MSI)  += ppc4xx_hsta_msi.o
 obj-$(CONFIG_PPC4xx_MSI)       += ppc4xx_msi.o
 obj-$(CONFIG_PPC4xx_CPM)       += ppc4xx_cpm.o
 obj-$(CONFIG_PPC4xx_GPIO)      += ppc4xx_gpio.o
diff --git a/arch/powerpc/sysdev/ppc4xx_hsta_msi.c 
b/arch/powerpc/sysdev/ppc4xx_hsta_msi.c
new file mode 100644
index 0000000..11c8884
--- /dev/null
+++ b/arch/powerpc/sysdev/ppc4xx_hsta_msi.c
@@ -0,0 +1,215 @@
+/*
+ * MSI support for PPC4xx SoCs using High Speed Transfer Assist (HSTA) for
+ * generation of the interrupt.
+ *
+ * Copyright © 2013 Alistair Popple <alist...@popple.id.au> IBM Corporation
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/msi.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/pci.h>
+#include <linux/semaphore.h>
+#include <asm/msi_bitmap.h>
+
+struct ppc4xx_hsta_msi {
+       struct device *dev;
+
+       /* The ioremapped HSTA MSI IO space */
+       u32 __iomem *data;
+
+       /* Physical address of HSTA MSI IO space */
+       u64 address;
+       struct msi_bitmap bmp;
+
+       /* An array mapping offsets to hardware IRQs */
+       int *irq_map;
+
+       /* Number of hwirqs supported */
+       int irq_count;
+};
+static struct ppc4xx_hsta_msi ppc4xx_hsta_msi;
+
+static int hsta_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
+{
+       struct msi_msg msg;
+       struct msi_desc *entry;
+       int irq, hwirq;
+       u64 addr;
+
+       list_for_each_entry(entry, &dev->msi_list, list) {
+               irq = msi_bitmap_alloc_hwirqs(&ppc4xx_hsta_msi.bmp, 1);
+               if (irq < 0) {
+                       pr_debug("%s: Failed to allocate msi interrupt\n",
+                                __func__);
+                       return irq;
+               }
+
+               hwirq = ppc4xx_hsta_msi.irq_map[irq];
+               if (hwirq == NO_IRQ) {
+                       pr_err("%s: Failed mapping irq %d\n", __func__, irq);
+                       return -EINVAL;
+               }
+
+               /*
+                * HSTA generates interrupts on writes to 128-bit aligned
+                * addresses.
+                */
+               addr = ppc4xx_hsta_msi.address + irq*0x10;
+               msg.address_hi = upper_32_bits(addr);
+               msg.address_lo = lower_32_bits(addr);
+
+               /* Data is not used by the HSTA. */
+               msg.data = 0;
+
+               pr_debug("%s: Setup irq %d (0x%0llx)\n", __func__, hwirq,
+                        (((u64) msg.address_hi) << 32) | msg.address_lo);
+
+               if (irq_set_msi_desc(hwirq, entry)) {
+                       pr_err(
+                       "%s: Invalid hwirq %d specified in device tree\n",
+                       __func__, hwirq);
+                       msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
+                       return -EINVAL;
+               }
+               write_msi_msg(hwirq, &msg);
+       }
+
+       return 0;
+}
+
+static int hsta_find_hwirq_offset(int hwirq)
+{
+       int irq;
+
+       /* Find the offset given the hwirq */
+       for (irq = 0; irq < ppc4xx_hsta_msi.irq_count; irq++)
+               if (ppc4xx_hsta_msi.irq_map[irq] == hwirq)
+                       return irq;
+
+       return -EINVAL;
+}
+
+static void hsta_teardown_msi_irqs(struct pci_dev *dev)
+{
+       struct msi_desc *entry;
+       int irq;
+
+       list_for_each_entry(entry, &dev->msi_list, list) {
+               if (entry->irq == NO_IRQ)
+                       continue;
+
+               irq = hsta_find_hwirq_offset(entry->irq);
+
+               /* entry->irq should always be in irq_map */
+               BUG_ON(irq < 0);
+               irq_set_msi_desc(entry->irq, NULL);
+               msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
+               pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__,
+                        entry->irq, irq);
+       }
+}
+
+static int hsta_msi_check_device(struct pci_dev *pdev, int nvec, int type)
+{
+       /* We don't support MSI-X */
+       if (type == PCI_CAP_ID_MSIX) {
+               pr_debug("%s: MSI-X not supported.\n", __func__);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static int hsta_msi_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct resource *mem;
+       int irq, ret, irq_count;
+
+       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (IS_ERR(mem)) {
+               dev_err(dev, "Unable to get mmio space\n");
+               return -EINVAL;
+       }
+
+       irq_count = of_irq_count(dev->of_node);
+       if (!irq_count) {
+               dev_err(dev, "Unable to find IRQ range\n");
+               return -EINVAL;
+       }
+
+       ppc4xx_hsta_msi.dev = dev;
+       ppc4xx_hsta_msi.address = mem->start;
+       ppc4xx_hsta_msi.data = ioremap(mem->start, resource_size(mem));
+       ppc4xx_hsta_msi.irq_count = irq_count;
+       if (IS_ERR(ppc4xx_hsta_msi.data)) {
+               dev_err(dev, "Unable to map memory\n");
+               return -ENOMEM;
+       }
+
+       ret = msi_bitmap_alloc(&ppc4xx_hsta_msi.bmp, irq_count, dev->of_node);
+       if (ret)
+               goto out;
+
+       ppc4xx_hsta_msi.irq_map = kmalloc(sizeof(int) * irq_count, GFP_KERNEL);
+       if (IS_ERR(ppc4xx_hsta_msi.irq_map)) {
+               ret = -ENOMEM;
+               goto out1;
+       }
+
+       /* Setup a mapping from irq offsets to hardware irq numbers */
+       for (irq = 0; irq < irq_count; irq++) {
+               ppc4xx_hsta_msi.irq_map[irq] =
+                       irq_of_parse_and_map(dev->of_node, irq);
+               if (ppc4xx_hsta_msi.irq_map[irq] == NO_IRQ) {
+                       dev_err(dev, "Unable to map IRQ\n");
+                       ret = -EINVAL;
+                       goto out2;
+               }
+       }
+
+       ppc_md.setup_msi_irqs = hsta_setup_msi_irqs;
+       ppc_md.teardown_msi_irqs = hsta_teardown_msi_irqs;
+       ppc_md.msi_check_device = hsta_msi_check_device;
+       return 0;
+
+out2:
+       kfree(ppc4xx_hsta_msi.irq_map);
+
+out1:
+       msi_bitmap_free(&ppc4xx_hsta_msi.bmp);
+
+out:
+       iounmap(ppc4xx_hsta_msi.data);
+       return ret;
+}
+
+static const struct of_device_id hsta_msi_ids[] = {
+       {
+               .compatible = "ibm,hsta-msi",
+       },
+       {}
+};
+
+static struct platform_driver hsta_msi_driver = {
+       .probe = hsta_msi_probe,
+       .driver = {
+               .name = "hsta-msi",
+               .owner = THIS_MODULE,
+               .of_match_table = hsta_msi_ids,
+       },
+};
+
+static int hsta_msi_init(void)
+{
+       return platform_driver_register(&hsta_msi_driver);
+}
+subsys_initcall(hsta_msi_init);
diff --git a/arch/powerpc/sysdev/ppc4xx_pci.c b/arch/powerpc/sysdev/ppc4xx_pci.c
index 54ec1d5..7cc3acc 100644
--- a/arch/powerpc/sysdev/ppc4xx_pci.c
+++ b/arch/powerpc/sysdev/ppc4xx_pci.c
@@ -176,8 +176,12 @@ static int __init ppc4xx_parse_dma_ranges(struct 
pci_controller *hose,
                return -ENXIO;
        }
 
-       /* Check that we are fully contained within 32 bits space */
-       if (res->end > 0xffffffff) {
+       /* Check that we are fully contained within 32 bits space if we are not
+        * running on a 460sx or 476fpe which have 64 bit bus addresses.
+        */
+       if (res->end > 0xffffffff &&
+           !(of_device_is_compatible(hose->dn, "ibm,plb-pciex-460sx")
+             || of_device_is_compatible(hose->dn, "ibm,plb-pciex-476fpe"))) {
                printk(KERN_ERR "%s: dma-ranges outside of 32 bits space\n",
                       hose->dn->full_name);
                return -ENXIO;
-- 
1.8.3.2

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