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Date: Mon, 28 Jul 2008 13:38:59 -0400
From: Matthew Wilcox <matthew@....cx>
To: jbarnes@...tuousgeek.org
Cc: linux-kernel@...r.kernel.org, eric@...olt.net,
Matthew Wilcox <matthew@....cx>,
Matthew Wilcox <willy@...ux.intel.com>
Subject: [PATCH 1/3] Rewrite PCI BAR reading code
Factor out the code to read one BAR from the loop in pci_read_bases into
a new function, __pci_read_base. The new code is slightly more
readable, better commented and removes the ifdef.
Signed-off-by: Matthew Wilcox <willy@...ux.intel.com>
---
drivers/pci/probe.c | 242 ++++++++++++++++++++++++++-------------------------
1 files changed, 123 insertions(+), 119 deletions(-)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b1724cf..3b690c3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -163,12 +163,9 @@ static inline unsigned int pci_calc_resource_flags(unsigned int flags)
return IORESOURCE_MEM;
}
-/*
- * Find the extent of a PCI decode..
- */
-static u32 pci_size(u32 base, u32 maxbase, u32 mask)
+static u64 pci_size(u64 base, u64 maxbase, u64 mask)
{
- u32 size = mask & maxbase; /* Find the significant bits */
+ u64 size = mask & maxbase; /* Find the significant bits */
if (!size)
return 0;
@@ -184,135 +181,142 @@ static u32 pci_size(u32 base, u32 maxbase, u32 mask)
return size;
}
-static u64 pci_size64(u64 base, u64 maxbase, u64 mask)
-{
- u64 size = mask & maxbase; /* Find the significant bits */
- if (!size)
- return 0;
+enum pci_bar_type {
+ pci_bar_unknown, /* Standard PCI BAR probe */
+ pci_bar_io, /* An io port BAR */
+ pci_bar_mem32, /* A 32-bit memory BAR */
+ pci_bar_mem64, /* A 64-bit memory BAR */
+};
- /* Get the lowest of them to find the decode size, and
- from that the extent. */
- size = (size & ~(size-1)) - 1;
+static inline enum pci_bar_type decode_bar(struct resource *res, u32 bar)
+{
+ if ((bar & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
+ res->flags = bar & ~PCI_BASE_ADDRESS_IO_MASK;
+ return pci_bar_io;
+ }
- /* base == maxbase can be valid only if the BAR has
- already been programmed with all 1s. */
- if (base == maxbase && ((base | size) & mask) != mask)
- return 0;
+ res->flags = bar & ~PCI_BASE_ADDRESS_MEM_MASK;
- return size;
+ if (res->flags == PCI_BASE_ADDRESS_MEM_TYPE_64)
+ return pci_bar_mem64;
+ return pci_bar_mem32;
}
-static inline int is_64bit_memory(u32 mask)
+/*
+ * If the type is not unknown, we assume that the lowest bit is 'enable'.
+ * Returns 1 if the BAR was 64-bit and 0 if it was 32-bit.
+ */
+static int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
+ struct resource *res, unsigned int pos)
{
- if ((mask & (PCI_BASE_ADDRESS_SPACE|PCI_BASE_ADDRESS_MEM_TYPE_MASK)) ==
- (PCI_BASE_ADDRESS_SPACE_MEMORY|PCI_BASE_ADDRESS_MEM_TYPE_64))
- return 1;
- return 0;
-}
+ u32 l, sz, mask;
-static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
-{
- unsigned int pos, reg, next;
- u32 l, sz;
- struct resource *res;
+ mask = type ? ~PCI_ROM_ADDRESS_ENABLE : ~0;
- for(pos=0; pos<howmany; pos = next) {
- u64 l64;
- u64 sz64;
- u32 raw_sz;
+ res->name = pci_name(dev);
- next = pos+1;
- res = &dev->resource[pos];
- res->name = pci_name(dev);
- reg = PCI_BASE_ADDRESS_0 + (pos << 2);
- pci_read_config_dword(dev, reg, &l);
- pci_write_config_dword(dev, reg, ~0);
- pci_read_config_dword(dev, reg, &sz);
- pci_write_config_dword(dev, reg, l);
- if (!sz || sz == 0xffffffff)
- continue;
- if (l == 0xffffffff)
- l = 0;
- raw_sz = sz;
- if ((l & PCI_BASE_ADDRESS_SPACE) ==
- PCI_BASE_ADDRESS_SPACE_MEMORY) {
- sz = pci_size(l, sz, (u32)PCI_BASE_ADDRESS_MEM_MASK);
- /*
- * For 64bit prefetchable memory sz could be 0, if the
- * real size is bigger than 4G, so we need to check
- * szhi for that.
- */
- if (!is_64bit_memory(l) && !sz)
- continue;
- res->start = l & PCI_BASE_ADDRESS_MEM_MASK;
- res->flags |= l & ~PCI_BASE_ADDRESS_MEM_MASK;
+ pci_read_config_dword(dev, pos, &l);
+ pci_write_config_dword(dev, pos, mask);
+ pci_read_config_dword(dev, pos, &sz);
+ pci_write_config_dword(dev, pos, l);
+
+ /*
+ * All bits set in sz means the device isn't working properly.
+ * If the BAR isn't implemented, all bits must be 0. If it's a
+ * memory BAR or a ROM, bit 0 must be clear; if it's an io BAR, bit
+ * 1 must be clear.
+ */
+ if (!sz || sz == 0xffffffff)
+ goto fail;
+
+ /*
+ * I don't know how l can have all bits set. Copied from old code.
+ * Maybe it fixes a bug on some ancient platform.
+ */
+ if (l == 0xffffffff)
+ l = 0;
+
+ if (type == pci_bar_unknown) {
+ type = decode_bar(res, l);
+ res->flags |= pci_calc_resource_flags(l) | IORESOURCE_SIZEALIGN;
+ if (type == pci_bar_io) {
+ l &= PCI_BASE_ADDRESS_IO_MASK;
+ mask = PCI_BASE_ADDRESS_IO_MASK & 0xffff;
} else {
- sz = pci_size(l, sz, PCI_BASE_ADDRESS_IO_MASK & 0xffff);
- if (!sz)
- continue;
- res->start = l & PCI_BASE_ADDRESS_IO_MASK;
- res->flags |= l & ~PCI_BASE_ADDRESS_IO_MASK;
+ l &= PCI_BASE_ADDRESS_MEM_MASK;
+ mask = (u32)PCI_BASE_ADDRESS_MEM_MASK;
}
- res->end = res->start + (unsigned long) sz;
- res->flags |= pci_calc_resource_flags(l) | IORESOURCE_SIZEALIGN;
- if (is_64bit_memory(l)) {
- u32 szhi, lhi;
-
- pci_read_config_dword(dev, reg+4, &lhi);
- pci_write_config_dword(dev, reg+4, ~0);
- pci_read_config_dword(dev, reg+4, &szhi);
- pci_write_config_dword(dev, reg+4, lhi);
- sz64 = ((u64)szhi << 32) | raw_sz;
- l64 = ((u64)lhi << 32) | l;
- sz64 = pci_size64(l64, sz64, PCI_BASE_ADDRESS_MEM_MASK);
- next++;
-#if BITS_PER_LONG == 64
- if (!sz64) {
- res->start = 0;
- res->end = 0;
- res->flags = 0;
- continue;
- }
- res->start = l64 & PCI_BASE_ADDRESS_MEM_MASK;
- res->end = res->start + sz64;
-#else
- if (sz64 > 0x100000000ULL) {
- dev_err(&dev->dev, "BAR %d: can't handle 64-bit"
- " BAR\n", pos);
- res->start = 0;
- res->flags = 0;
- } else if (lhi) {
- /* 64-bit wide address, treat as disabled */
- pci_write_config_dword(dev, reg,
- l & ~(u32)PCI_BASE_ADDRESS_MEM_MASK);
- pci_write_config_dword(dev, reg+4, 0);
- res->start = 0;
- res->end = sz;
- }
-#endif
+ } else {
+ res->flags |= (l & IORESOURCE_ROM_ENABLE);
+ l &= PCI_ROM_ADDRESS_MASK;
+ mask = (u32)PCI_ROM_ADDRESS_MASK;
+ }
+
+ if (type == pci_bar_mem64) {
+ u64 l64 = l;
+ u64 sz64 = sz;
+ u64 mask64 = mask | (u64)~0 << 32;
+
+ pci_read_config_dword(dev, pos + 4, &l);
+ pci_write_config_dword(dev, pos + 4, ~0);
+ pci_read_config_dword(dev, pos + 4, &sz);
+ pci_write_config_dword(dev, pos + 4, l);
+
+ l64 |= ((u64)l << 32);
+ sz64 |= ((u64)sz << 32);
+
+ sz64 = pci_size(l64, sz64, mask64);
+
+ if (!sz64)
+ goto fail;
+
+ if ((BITS_PER_LONG < 64) && (sz64 > 0x100000000ULL)) {
+ dev_err(&dev->dev, "can't handle 64-bit BAR\n");
+ goto fail;
+ } else if ((BITS_PER_LONG < 64) && l) {
+ /* Address above 32-bit boundary; disable the BAR */
+ pci_write_config_dword(dev, pos, 0);
+ pci_write_config_dword(dev, pos + 4, 0);
+ res->start = 0;
+ res->end = sz64;
+ } else {
+ res->start = l64;
+ res->end = l64 + sz64;
}
+ } else {
+ sz = pci_size(l, sz, mask);
+
+ if (!sz)
+ goto fail;
+
+ res->start = l;
+ res->end = l + sz;
}
+
+ out:
+ return (type == pci_bar_mem64) ? 1 : 0;
+ fail:
+ res->flags = 0;
+ goto out;
+}
+
+static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
+{
+ unsigned int pos, reg;
+
+ for (pos = 0; pos < howmany; pos++) {
+ struct resource *res = &dev->resource[pos];
+ reg = PCI_BASE_ADDRESS_0 + (pos << 2);
+ pos += __pci_read_base(dev, pci_bar_unknown, res, reg);
+ }
+
if (rom) {
+ struct resource *res = &dev->resource[PCI_ROM_RESOURCE];
dev->rom_base_reg = rom;
- res = &dev->resource[PCI_ROM_RESOURCE];
- res->name = pci_name(dev);
- pci_read_config_dword(dev, rom, &l);
- pci_write_config_dword(dev, rom, ~PCI_ROM_ADDRESS_ENABLE);
- pci_read_config_dword(dev, rom, &sz);
- pci_write_config_dword(dev, rom, l);
- if (l == 0xffffffff)
- l = 0;
- if (sz && sz != 0xffffffff) {
- sz = pci_size(l, sz, (u32)PCI_ROM_ADDRESS_MASK);
- if (sz) {
- res->flags = (l & IORESOURCE_ROM_ENABLE) |
- IORESOURCE_MEM | IORESOURCE_PREFETCH |
- IORESOURCE_READONLY | IORESOURCE_CACHEABLE |
- IORESOURCE_SIZEALIGN;
- res->start = l & PCI_ROM_ADDRESS_MASK;
- res->end = res->start + (unsigned long) sz;
- }
- }
+ res->flags = IORESOURCE_MEM | IORESOURCE_PREFETCH |
+ IORESOURCE_READONLY | IORESOURCE_CACHEABLE |
+ IORESOURCE_SIZEALIGN;
+ __pci_read_base(dev, pci_bar_mem32, res, rom);
}
}
--
1.5.5.4
--
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