From: Bjorn Helgaas <helgaas@kernel.org>
To: Geliang Tang <geliangtang@163.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/PCI: simplify pci_bios_{read,write}
Date: Wed, 9 Dec 2015 10:50:46 -0600 [thread overview]
Message-ID: <20151209165046.GF31930@localhost> (raw)
In-Reply-To: <0ed29e57b699af22a8759f1b1c0d59d79664dee5.1449495573.git.geliangtang@163.com>
On Mon, Dec 07, 2015 at 10:24:24PM +0800, Geliang Tang wrote:
> There are some repetitive code in the switch/case statement in
> pci_bios_read() and pci_bios_write(). I drop it to simplify the
> code.
>
> Signed-off-by: Geliang Tang <geliangtang@163.com>
Applied to pci/misc for v4.5 with Thomas' Reviewed-by, thanks!
> ---
> arch/x86/pci/pcbios.c | 108 ++++++++++++++++++--------------------------------
> 1 file changed, 38 insertions(+), 70 deletions(-)
>
> diff --git a/arch/x86/pci/pcbios.c b/arch/x86/pci/pcbios.c
> index 9b83b90..9770e55 100644
> --- a/arch/x86/pci/pcbios.c
> +++ b/arch/x86/pci/pcbios.c
> @@ -180,6 +180,7 @@ static int pci_bios_read(unsigned int seg, unsigned int bus,
> unsigned long result = 0;
> unsigned long flags;
> unsigned long bx = (bus << 8) | devfn;
> + u16 number = 0, mask = 0;
>
> WARN_ON(seg);
> if (!value || (bus > 255) || (devfn > 255) || (reg > 255))
> @@ -189,53 +190,35 @@ static int pci_bios_read(unsigned int seg, unsigned int bus,
>
> switch (len) {
> case 1:
> - __asm__("lcall *(%%esi); cld\n\t"
> - "jc 1f\n\t"
> - "xor %%ah, %%ah\n"
> - "1:"
> - : "=c" (*value),
> - "=a" (result)
> - : "1" (PCIBIOS_READ_CONFIG_BYTE),
> - "b" (bx),
> - "D" ((long)reg),
> - "S" (&pci_indirect));
> - /*
> - * Zero-extend the result beyond 8 bits, do not trust the
> - * BIOS having done it:
> - */
> - *value &= 0xff;
> + number = PCIBIOS_READ_CONFIG_BYTE;
> + mask = 0xff;
> break;
> case 2:
> - __asm__("lcall *(%%esi); cld\n\t"
> - "jc 1f\n\t"
> - "xor %%ah, %%ah\n"
> - "1:"
> - : "=c" (*value),
> - "=a" (result)
> - : "1" (PCIBIOS_READ_CONFIG_WORD),
> - "b" (bx),
> - "D" ((long)reg),
> - "S" (&pci_indirect));
> - /*
> - * Zero-extend the result beyond 16 bits, do not trust the
> - * BIOS having done it:
> - */
> - *value &= 0xffff;
> + number = PCIBIOS_READ_CONFIG_WORD;
> + mask = 0xffff;
> break;
> case 4:
> - __asm__("lcall *(%%esi); cld\n\t"
> - "jc 1f\n\t"
> - "xor %%ah, %%ah\n"
> - "1:"
> - : "=c" (*value),
> - "=a" (result)
> - : "1" (PCIBIOS_READ_CONFIG_DWORD),
> - "b" (bx),
> - "D" ((long)reg),
> - "S" (&pci_indirect));
> + number = PCIBIOS_READ_CONFIG_DWORD;
> break;
> }
>
> + __asm__("lcall *(%%esi); cld\n\t"
> + "jc 1f\n\t"
> + "xor %%ah, %%ah\n"
> + "1:"
> + : "=c" (*value),
> + "=a" (result)
> + : "1" (number),
> + "b" (bx),
> + "D" ((long)reg),
> + "S" (&pci_indirect));
> + /*
> + * Zero-extend the result beyond 8 or 16 bits, do not trust the
> + * BIOS having done it:
> + */
> + if (mask)
> + *value &= mask;
> +
> raw_spin_unlock_irqrestore(&pci_config_lock, flags);
>
> return (int)((result & 0xff00) >> 8);
> @@ -247,6 +230,7 @@ static int pci_bios_write(unsigned int seg, unsigned int bus,
> unsigned long result = 0;
> unsigned long flags;
> unsigned long bx = (bus << 8) | devfn;
> + u16 number = 0;
>
> WARN_ON(seg);
> if ((bus > 255) || (devfn > 255) || (reg > 255))
> @@ -256,43 +240,27 @@ static int pci_bios_write(unsigned int seg, unsigned int bus,
>
> switch (len) {
> case 1:
> - __asm__("lcall *(%%esi); cld\n\t"
> - "jc 1f\n\t"
> - "xor %%ah, %%ah\n"
> - "1:"
> - : "=a" (result)
> - : "0" (PCIBIOS_WRITE_CONFIG_BYTE),
> - "c" (value),
> - "b" (bx),
> - "D" ((long)reg),
> - "S" (&pci_indirect));
> + number = PCIBIOS_WRITE_CONFIG_BYTE;
> break;
> case 2:
> - __asm__("lcall *(%%esi); cld\n\t"
> - "jc 1f\n\t"
> - "xor %%ah, %%ah\n"
> - "1:"
> - : "=a" (result)
> - : "0" (PCIBIOS_WRITE_CONFIG_WORD),
> - "c" (value),
> - "b" (bx),
> - "D" ((long)reg),
> - "S" (&pci_indirect));
> + number = PCIBIOS_WRITE_CONFIG_WORD;
> break;
> case 4:
> - __asm__("lcall *(%%esi); cld\n\t"
> - "jc 1f\n\t"
> - "xor %%ah, %%ah\n"
> - "1:"
> - : "=a" (result)
> - : "0" (PCIBIOS_WRITE_CONFIG_DWORD),
> - "c" (value),
> - "b" (bx),
> - "D" ((long)reg),
> - "S" (&pci_indirect));
> + number = PCIBIOS_WRITE_CONFIG_DWORD;
> break;
> }
>
> + __asm__("lcall *(%%esi); cld\n\t"
> + "jc 1f\n\t"
> + "xor %%ah, %%ah\n"
> + "1:"
> + : "=a" (result)
> + : "0" (number),
> + "c" (value),
> + "b" (bx),
> + "D" ((long)reg),
> + "S" (&pci_indirect));
> +
> raw_spin_unlock_irqrestore(&pci_config_lock, flags);
>
> return (int)((result & 0xff00) >> 8);
> --
> 2.5.0
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
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prev parent reply other threads:[~2015-12-09 16:50 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-07 13:42 [PATCH] x86/PCI: simplify pci_bios_{read,write} Geliang Tang
2015-12-08 12:16 ` Thomas Gleixner
2015-12-09 16:50 ` Bjorn Helgaas [this message]
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