[U-Boot] [PATCH v2] board/linkstation/ide.c: Fix compile warning

[Guennadi Liakhovetski]

On Tue, 15 Sep 2009, Wolfgang Denk wrote:

> Fix warning: ide.c:60: warning: dereferencing type-punned pointer will
> break strict-aliasing rules
> 
> Signed-off-by: Wolfgang Denk <wd at denx.de>
> Cc: Guennadi Liakhovetski <lg at denx.de>
> 
> ---
> v2: Better implementation as suggested by Scott Wood in
>     http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/67840/focus=67891
> 
>  board/linkstation/ide.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/board/linkstation/ide.c b/board/linkstation/ide.c
> index 2c89d62..568fdf5 100644
> --- a/board/linkstation/ide.c
> +++ b/board/linkstation/ide.c
> @@ -54,11 +54,13 @@ int ide_preinit (void)
>  	if (devbusfn == -1)
>  		devbusfn = pci_find_device(PCI_VENDOR_ID_ITE,PCI_DEVICE_ID_ITE_8212,0);
>  	if (devbusfn != -1) {
> +		u32 ide_bus_offset32;
> +
>  		status = 0;
>  
>  		pci_read_config_dword (devbusfn, PCI_BASE_ADDRESS_0,
> -							   (u32 *) &ide_bus_offset[0]);
> -		ide_bus_offset[0] &= 0xfffffffe;
> +							   &ide_bus_offset32);
> +		ide_bus_offset[0] = ide_bus_offset32 & 0xfffffffe;
>  		ide_bus_offset[0] = pci_hose_bus_to_phys(&hose,
>  							 ide_bus_offset[0] & 0xfffffffe,
>  							 PCI_REGION_IO);

Ok, yes, this looks much better now without casts, but - the double " & 
0xfffffffe" above seems completely redundant to me. I understand, that 
that's not the problem you're fixing with this patch, and I will perfectly 
understand if you refuse to mix these two fixes, but... Another thing - 
why doesn't the compiler complain about exactly identical cast (ok, 
almost) a couple of lines down for ide_bus_offset[1]? So, how about this 
diff instead (only compile-tested) (not for submission yet, so, no Sob's, 
no patch header):

diff --git a/board/linkstation/ide.c b/board/linkstation/ide.c
index 2c89d62..f96af74 100644
--- a/board/linkstation/ide.c
+++ b/board/linkstation/ide.c
@@ -54,20 +54,23 @@ int ide_preinit (void)
 	if (devbusfn == -1)
 		devbusfn = pci_find_device(PCI_VENDOR_ID_ITE,PCI_DEVICE_ID_ITE_8212,0);
 	if (devbusfn != -1) {
+		u32 ide_bus_offset32;
+
 		status = 0;
 
-		pci_read_config_dword (devbusfn, PCI_BASE_ADDRESS_0,
-							   (u32 *) &ide_bus_offset[0]);
-		ide_bus_offset[0] &= 0xfffffffe;
+		pci_read_config_dword(devbusfn, PCI_BASE_ADDRESS_0,
+				      &ide_bus_offset32);
+		ide_bus_offset[0] = ide_bus_offset32 & 0xfffffffe;
 		ide_bus_offset[0] = pci_hose_bus_to_phys(&hose,
-							 ide_bus_offset[0] & 0xfffffffe,
-							 PCI_REGION_IO);
-		pci_read_config_dword(devbusfn, PCI_BASE_ADDRESS_2,
-				      (u32 *) &ide_bus_offset[1]);
-		ide_bus_offset[1] &= 0xfffffffe;
-		ide_bus_offset[1] = pci_hose_bus_to_phys(&hose,
-							 ide_bus_offset[1] & 0xfffffffe,
-							 PCI_REGION_IO);
+					ide_bus_offset[0], PCI_REGION_IO);
+
+		if (CONFIG_SYS_IDE_MAXBUS > 1) {
+			pci_read_config_dword(devbusfn, PCI_BASE_ADDRESS_2,
+					      &ide_bus_offset32);
+			ide_bus_offset[1] = ide_bus_offset32 & 0xfffffffe;
+			ide_bus_offset[1] = pci_hose_bus_to_phys(&hose,
+					ide_bus_offset[1], PCI_REGION_IO);
+		}
 	}
 
 	if (pci_find_device (PCI_VENDOR_ID_ITE, PCI_DEVICE_ID_ITE_8212, 0) != -1) {

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/