sh: Enable PCI66 support for SH7780 host controller.

This adds some helper glue for scanning the bus and determining if all
of the devices are 66MHz capable or not before flipping on 66MHz mode.
This isn't quite to spec, but it's fairly consistent with what other
embedded controllers end up having to do.

Scanning code cribbed from the MIPS txx9 PCI code.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

diff --git a/arch/sh/drivers/pci/Makefile b/arch/sh/drivers/pci/Makefile
index 2c458b602beb95c911d7dc5db139b93daa2dbd82..4a59e6890876cd2d1546e991011c887c4a230983 100644 (file)
--- a/arch/sh/drivers/pci/Makefile
+++ b/arch/sh/drivers/pci/Makefile
@@ -1,7 +1,7 @@
 #
 # Makefile for the PCI specific kernel interface routines under Linux.
 #
-obj-y                                  += pci.o
+obj-y                                  += common.o pci.o
 
 obj-$(CONFIG_CPU_SUBTYPE_SH7751)       += pci-sh7751.o ops-sh4.o
 obj-$(CONFIG_CPU_SUBTYPE_SH7751R)      += pci-sh7751.o ops-sh4.o

diff --git a/arch/sh/drivers/pci/common.c b/arch/sh/drivers/pci/common.c
new file mode 100644 (file)
index 0000000..f67c946
--- /dev/null
+++ b/arch/sh/drivers/pci/common.c
@@ -0,0 +1,64 @@
+#include <linux/pci.h>
+#include <linux/kernel.h>
+
+static int __init
+early_read_config_word(struct pci_channel *hose,
+                      int top_bus, int bus, int devfn, int offset, u16 *value)
+{
+       struct pci_dev fake_dev;
+       struct pci_bus fake_bus;
+
+       fake_dev.bus = &fake_bus;
+       fake_dev.sysdata = hose;
+       fake_dev.devfn = devfn;
+       fake_bus.number = bus;
+       fake_bus.sysdata = hose;
+       fake_bus.ops = hose->pci_ops;
+
+       if (bus != top_bus)
+               /* Fake a parent bus structure. */
+               fake_bus.parent = &fake_bus;
+       else
+               fake_bus.parent = NULL;
+
+       return pci_read_config_word(&fake_dev, offset, value);
+}
+
+int __init pci_is_66mhz_capable(struct pci_channel *hose,
+                               int top_bus, int current_bus)
+{
+       u32 pci_devfn;
+       unsigned short vid;
+       int cap66 = -1;
+       u16 stat;
+
+       printk(KERN_INFO "PCI: Checking 66MHz capabilities...\n");
+
+       for (pci_devfn = 0; pci_devfn < 0xff; pci_devfn++) {
+               if (PCI_FUNC(pci_devfn))
+                       continue;
+               if (early_read_config_word(hose, top_bus, current_bus,
+                                          pci_devfn, PCI_VENDOR_ID, &vid) !=
+                   PCIBIOS_SUCCESSFUL)
+                       continue;
+               if (vid == 0xffff)
+                       continue;
+
+               /* check 66MHz capability */
+               if (cap66 < 0)
+                       cap66 = 1;
+               if (cap66) {
+                       early_read_config_word(hose, top_bus, current_bus,
+                                              pci_devfn, PCI_STATUS, &stat);
+                       if (!(stat & PCI_STATUS_66MHZ)) {
+                               printk(KERN_DEBUG
+                                      "PCI: %02x:%02x not 66MHz capable.\n",
+                                      current_bus, pci_devfn);
+                               cap66 = 0;
+                               break;
+                       }
+               }
+       }
+
+       return cap66 > 0;
+}

diff --git a/arch/sh/drivers/pci/pci-sh7780.c b/arch/sh/drivers/pci/pci-sh7780.c
index 8405c8fded6f9cb891a14813550ad672159721a7..b68f45b6451a3ad7478b6ac402cc9f13539c0ac2 100644 (file)
--- a/arch/sh/drivers/pci/pci-sh7780.c
+++ b/arch/sh/drivers/pci/pci-sh7780.c
@@ -41,6 +41,29 @@ static struct pci_channel sh7780_pci_controller = {
        .io_map_base    = SH7780_PCI_IO_BASE,
 };
 
+static void __init sh7780_pci66_init(struct pci_channel *hose)
+{
+       unsigned int tmp;
+
+       if (!pci_is_66mhz_capable(hose, 0, 0))
+               return;
+
+       /* Enable register access */
+       tmp = __raw_readl(hose->reg_base + SH4_PCICR);
+       tmp |= SH4_PCICR_PREFIX;
+       __raw_writel(tmp, hose->reg_base + SH4_PCICR);
+
+       /* Enable 66MHz operation */
+       tmp = __raw_readw(hose->reg_base + PCI_STATUS);
+       tmp |= PCI_STATUS_66MHZ;
+       __raw_writew(tmp, hose->reg_base + PCI_STATUS);
+
+       /* Done */
+       tmp = __raw_readl(hose->reg_base + SH4_PCICR);
+       tmp |= SH4_PCICR_PREFIX | SH4_PCICR_CFIN;
+       __raw_writel(tmp, hose->reg_base + SH4_PCICR);
+}
+
 static int __init sh7780_pci_init(void)
 {
        struct pci_channel *chan = &sh7780_pci_controller;
@@ -176,6 +199,12 @@ static int __init sh7780_pci_init(void)
 
        register_pci_controller(chan);
 
+       sh7780_pci66_init(chan);
+
+       printk(KERN_NOTICE "PCI: Running at %dMHz.\n",
+              (__raw_readw(chan->reg_base + PCI_STATUS) & PCI_STATUS_66MHZ) ?
+              66 : 33);
+
        return 0;
 }
 arch_initcall(sh7780_pci_init);

diff --git a/arch/sh/drivers/pci/pci.c b/arch/sh/drivers/pci/pci.c
index 45a15cab01df0b0d92225a33c0424b7b90960c8b..63b11fddffecdda25145d749043cc23773122c07 100644 (file)
--- a/arch/sh/drivers/pci/pci.c
+++ b/arch/sh/drivers/pci/pci.c
@@ -88,6 +88,8 @@ void __devinit register_pci_controller(struct pci_channel *hose)
                mutex_unlock(&pci_scan_mutex);
        }
 
+       return;
+
 out:
        printk(KERN_WARNING "Skipping PCI bus scan due to resource conflict\n");
 }

diff --git a/arch/sh/include/asm/pci.h b/arch/sh/include/asm/pci.h
index d124a009889f670cd6d2c2e50373e6e092ef7bf2..5849d435c441968f3873ffea6575989b5869d5d7 100644 (file)
--- a/arch/sh/include/asm/pci.h
+++ b/arch/sh/include/asm/pci.h
@@ -32,6 +32,8 @@ struct pci_channel {
 };
 
 extern void register_pci_controller(struct pci_channel *hose);
+extern int pci_is_66mhz_capable(struct pci_channel *hose,
+                               int top_bus, int current_bus);
 
 extern unsigned long PCIBIOS_MIN_IO, PCIBIOS_MIN_MEM;