PCI: fix access of PCI_X_CMD by pcix get and set mmrbc functions

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From: Linux Kernel Mailing List
Date: Friday, March 26, 2010 - 4:59 pm

Gitweb:     http://git.kernel.org/linus/bdc2bda7c4dd253026cc1fce45fc939304749029
Commit:     bdc2bda7c4dd253026cc1fce45fc939304749029
Parent:     ded1d8f29b4d315a2093cafc3ee17ac870a87972
Author:     Dean Nelson <dnelson@redhat.com>
AuthorDate: Tue Mar 9 22:26:48 2010 -0500
Committer:  Jesse Barnes <jbarnes@virtuousgeek.org>
CommitDate: Fri Mar 19 12:40:22 2010 -0700

    PCI: fix access of PCI_X_CMD by pcix get and set mmrbc functions
    
    An e1000 driver on a system with a PCI-X bus was always being returned
    a value of 135 from both pcix_get_mmrbc() and pcix_set_mmrbc(). This
    value reflects an error return of PCIBIOS_BAD_REGISTER_NUMBER from
    pci_bus_read_config_dword(,, cap + PCI_X_CMD,).
    
    This is because for a dword, the following portion of the PCI_OP_READ()
    macro:
    
    	if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER;
    
    expands to:
    
    	if (pos & 3) return PCIBIOS_BAD_REGISTER_NUMBER;
    
    And is always true for 'cap + PCI_X_CMD', which is 0xe4 + 2 = 0xe6. ('cap' is
    the result of calling pci_find_capability(, PCI_CAP_ID_PCIX).)
    
    The same problem exists for pci_bus_write_config_dword(,, cap + PCI_X_CMD,).
    In both cases, instead of calling _dword(), _word() should be called.
    
    Cc: stable@kernel.org
    Signed-off-by: Dean Nelson <dnelson@redhat.com>
    Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
---
 drivers/pci/pci.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 9af9860..5c80b59 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2601,13 +2601,13 @@ EXPORT_SYMBOL(pcix_get_max_mmrbc);
 int pcix_get_mmrbc(struct pci_dev *dev)
 {
 	int ret, cap;
-	u32 cmd;
+	u16 cmd;
 
 	cap = pci_find_capability(dev, PCI_CAP_ID_PCIX);
 	if (!cap)
 		return -EINVAL;
 
-	ret = pci_read_config_dword(dev, cap + PCI_X_CMD, &cmd);
+	ret = pci_read_config_word(dev, cap + PCI_X_CMD, &cmd);
 	if (!ret)
 		ret = 512 << ((cmd & PCI_X_CMD_MAX_READ) >> 2);
 
@@ -2627,7 +2627,8 @@ EXPORT_SYMBOL(pcix_get_mmrbc);
 int pcix_set_mmrbc(struct pci_dev *dev, int mmrbc)
 {
 	int cap, err = -EINVAL;
-	u32 stat, cmd, v, o;
+	u32 stat, v, o;
+	u16 cmd;
 
 	if (mmrbc < 512 || mmrbc > 4096 || !is_power_of_2(mmrbc))
 		goto out;
@@ -2645,7 +2646,7 @@ int pcix_set_mmrbc(struct pci_dev *dev, int mmrbc)
 	if (v > (stat & PCI_X_STATUS_MAX_READ) >> 21)
 		return -E2BIG;
 
-	err = pci_read_config_dword(dev, cap + PCI_X_CMD, &cmd);
+	err = pci_read_config_word(dev, cap + PCI_X_CMD, &cmd);
 	if (err)
 		goto out;
 
@@ -2657,7 +2658,7 @@ int pcix_set_mmrbc(struct pci_dev *dev, int mmrbc)
 
 		cmd &= ~PCI_X_CMD_MAX_READ;
 		cmd |= v << 2;
-		err = pci_write_config_dword(dev, cap + PCI_X_CMD, cmd);
+		err = pci_write_config_word(dev, cap + PCI_X_CMD, cmd);
 	}
 out:
 	return err;
--
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PCI: fix access of PCI_X_CMD by pcix get and set mmrbc fun ..., Linux Kernel Mailing ..., (Fri Mar 26, 4:59 pm)