[v2,1/1] x86/PCI: Clean up open-coded return code mangling
Commit Message
PCI BIOS gives a return code in 8 bits of eax register which is
extracted by open-coded masks and shifting.
Name the return code bits with a define and introduce
pcibios_get_return_code() helper to extract the return code to improve
code readability. In addition, replace a zero test with
PCIBIOS_SUCCESSFUL.
No function changes intended.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
v2:
- Improve changelog
- Add helper to avoid repeating FIELD_GET()
- Reuse existing ret variable in pcibios_get_irq_routing_table()
arch/x86/pci/pcbios.c | 26 ++++++++++++++++++++------
1 file changed, 20 insertions(+), 6 deletions(-)
Comments
On Fri, Oct 27, 2023 at 12:31:58PM +0300, Ilpo Järvinen wrote:
> PCI BIOS gives a return code in 8 bits of eax register which is
> extracted by open-coded masks and shifting.
>
> Name the return code bits with a define and introduce
> pcibios_get_return_code() helper to extract the return code to improve
> code readability. In addition, replace a zero test with
> PCIBIOS_SUCCESSFUL.
>
> No function changes intended.
>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Applied to the PCI "enumeration" branch for v6.8. x86 folks, if you'd
prefer to take this, let me know.
> ---
>
> v2:
> - Improve changelog
> - Add helper to avoid repeating FIELD_GET()
> - Reuse existing ret variable in pcibios_get_irq_routing_table()
>
> arch/x86/pci/pcbios.c | 26 ++++++++++++++++++++------
> 1 file changed, 20 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/pci/pcbios.c b/arch/x86/pci/pcbios.c
> index 4f15280732ed..01c94ac2fb70 100644
> --- a/arch/x86/pci/pcbios.c
> +++ b/arch/x86/pci/pcbios.c
> @@ -3,6 +3,8 @@
> * BIOS32 and PCI BIOS handling.
> */
>
> +#include <linux/bits.h>
> +#include <linux/bitfield.h>
> #include <linux/pci.h>
> #include <linux/init.h>
> #include <linux/slab.h>
> @@ -29,8 +31,19 @@
> #define PCIBIOS_HW_TYPE1_SPEC 0x10
> #define PCIBIOS_HW_TYPE2_SPEC 0x20
>
> +/*
> + * Returned in EAX:
> + * - AH: return code
> + */
> +#define PCIBIOS_RETURN_CODE GENMASK(15, 8)
> +
> int pcibios_enabled;
>
> +static u8 pcibios_get_return_code(u32 eax)
> +{
> + return FIELD_GET(PCIBIOS_RETURN_CODE, eax);
> +}
> +
> /* According to the BIOS specification at:
> * http://members.datafast.net.au/dft0802/specs/bios21.pdf, we could
> * restrict the x zone to some pages and make it ro. But this may be
> @@ -154,7 +167,7 @@ static int __init check_pcibios(void)
> : "memory");
> local_irq_restore(flags);
>
> - status = (eax >> 8) & 0xff;
> + status = pcibios_get_return_code(eax);
> hw_mech = eax & 0xff;
> major_ver = (ebx >> 8) & 0xff;
> minor_ver = ebx & 0xff;
> @@ -227,7 +240,7 @@ static int pci_bios_read(unsigned int seg, unsigned int bus,
>
> raw_spin_unlock_irqrestore(&pci_config_lock, flags);
>
> - return (int)((result & 0xff00) >> 8);
> + return pcibios_get_return_code(result);
> }
>
> static int pci_bios_write(unsigned int seg, unsigned int bus,
> @@ -269,7 +282,7 @@ static int pci_bios_write(unsigned int seg, unsigned int bus,
>
> raw_spin_unlock_irqrestore(&pci_config_lock, flags);
>
> - return (int)((result & 0xff00) >> 8);
> + return pcibios_get_return_code(result);
> }
>
>
> @@ -385,8 +398,9 @@ struct irq_routing_table * pcibios_get_irq_routing_table(void)
> "m" (opt)
> : "memory");
> DBG("OK ret=%d, size=%d, map=%x\n", ret, opt.size, map);
> - if (ret & 0xff00)
> - printk(KERN_ERR "PCI: Error %02x when fetching IRQ routing table.\n", (ret >> 8) & 0xff);
> + ret = pcibios_get_return_code(ret);
> + if (ret)
> + printk(KERN_ERR "PCI: Error %02x when fetching IRQ routing table.\n", ret);
> else if (opt.size) {
> rt = kmalloc(sizeof(struct irq_routing_table) + opt.size, GFP_KERNEL);
> if (rt) {
> @@ -415,7 +429,7 @@ int pcibios_set_irq_routing(struct pci_dev *dev, int pin, int irq)
> "b" ((dev->bus->number << 8) | dev->devfn),
> "c" ((irq << 8) | (pin + 10)),
> "S" (&pci_indirect));
> - return !(ret & 0xff00);
> + return pcibios_get_return_code(ret) == PCIBIOS_SUCCESSFUL;
> }
> EXPORT_SYMBOL(pcibios_set_irq_routing);
>
> --
> 2.30.2
>
@@ -3,6 +3,8 @@
* BIOS32 and PCI BIOS handling.
*/
+#include <linux/bits.h>
+#include <linux/bitfield.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/slab.h>
@@ -29,8 +31,19 @@
#define PCIBIOS_HW_TYPE1_SPEC 0x10
#define PCIBIOS_HW_TYPE2_SPEC 0x20
+/*
+ * Returned in EAX:
+ * - AH: return code
+ */
+#define PCIBIOS_RETURN_CODE GENMASK(15, 8)
+
int pcibios_enabled;
+static u8 pcibios_get_return_code(u32 eax)
+{
+ return FIELD_GET(PCIBIOS_RETURN_CODE, eax);
+}
+
/* According to the BIOS specification at:
* http://members.datafast.net.au/dft0802/specs/bios21.pdf, we could
* restrict the x zone to some pages and make it ro. But this may be
@@ -154,7 +167,7 @@ static int __init check_pcibios(void)
: "memory");
local_irq_restore(flags);
- status = (eax >> 8) & 0xff;
+ status = pcibios_get_return_code(eax);
hw_mech = eax & 0xff;
major_ver = (ebx >> 8) & 0xff;
minor_ver = ebx & 0xff;
@@ -227,7 +240,7 @@ static int pci_bios_read(unsigned int seg, unsigned int bus,
raw_spin_unlock_irqrestore(&pci_config_lock, flags);
- return (int)((result & 0xff00) >> 8);
+ return pcibios_get_return_code(result);
}
static int pci_bios_write(unsigned int seg, unsigned int bus,
@@ -269,7 +282,7 @@ static int pci_bios_write(unsigned int seg, unsigned int bus,
raw_spin_unlock_irqrestore(&pci_config_lock, flags);
- return (int)((result & 0xff00) >> 8);
+ return pcibios_get_return_code(result);
}
@@ -385,8 +398,9 @@ struct irq_routing_table * pcibios_get_irq_routing_table(void)
"m" (opt)
: "memory");
DBG("OK ret=%d, size=%d, map=%x\n", ret, opt.size, map);
- if (ret & 0xff00)
- printk(KERN_ERR "PCI: Error %02x when fetching IRQ routing table.\n", (ret >> 8) & 0xff);
+ ret = pcibios_get_return_code(ret);
+ if (ret)
+ printk(KERN_ERR "PCI: Error %02x when fetching IRQ routing table.\n", ret);
else if (opt.size) {
rt = kmalloc(sizeof(struct irq_routing_table) + opt.size, GFP_KERNEL);
if (rt) {
@@ -415,7 +429,7 @@ int pcibios_set_irq_routing(struct pci_dev *dev, int pin, int irq)
"b" ((dev->bus->number << 8) | dev->devfn),
"c" ((irq << 8) | (pin + 10)),
"S" (&pci_indirect));
- return !(ret & 0xff00);
+ return pcibios_get_return_code(ret) == PCIBIOS_SUCCESSFUL;
}
EXPORT_SYMBOL(pcibios_set_irq_routing);