From: Dongdong Liu <liudongdong3@huawei.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: <helgaas@kernel.org>, <rafael@kernel.org>,
<Lorenzo.Pieralisi@arm.com>, <tn@semihalf.com>,
<wangzhou1@hisilicon.com>, <pratyush.anand@gmail.com>,
<linux-pci@vger.kernel.org>, <linux-acpi@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <jcm@redhat.com>,
<gabriele.paoloni@huawei.com>, <charles.chenxin@huawei.com>,
<hanjun.guo@linaro.org>, <linuxarm@huawei.com>
Subject: Re: [RFC PATCH V2 1/3] PCI: hisi: re-architect Hip05/Hip06 controllers driver to preapare for ACPI
Date: Thu, 1 Sep 2016 10:05:29 +0800 [thread overview]
Message-ID: <57C78CE9.3010707@huawei.com> (raw)
In-Reply-To: <4925807.5nZM1s8II1@wuerfel>
在 2016/8/31 19:45, Arnd Bergmann 写道:
> On Wednesday, August 31, 2016 7:48:12 PM CEST Dongdong Liu wrote:
>> +
>> +/* HipXX PCIe host only supports 32-bit config access */
>> +int hisi_pcie_common_cfg_read(void __iomem *reg_base, int where, int size,
>> + u32 *val)
>> +{
>> + u32 reg;
>> + u32 reg_val;
>> + void *walker = ®_val;
>> +
>> + walker += (where & 0x3);
>> + reg = where & ~0x3;
>> + reg_val = readl(reg_base + reg);
>> +
>> + if (size == 1)
>> + *val = *(u8 __force *) walker;
>> + else if (size == 2)
>> + *val = *(u16 __force *) walker;
>
> What is the __force for?
Hi Arnd, thanks for replying.
__force is used to, well, force a conversion, like casting from or to a bitwise type, else the Sparse checker will throw a warning.
>
>> + else if (size == 4)
>> + *val = reg_val;
>> + else
>> + return PCIBIOS_BAD_REGISTER_NUMBER;
>> +
>> + return PCIBIOS_SUCCESSFUL;
>
> It looks like you are reimplementing pci_generic_config_read32/pci_generic_config_write32
> read here, better use them directly.
>
For our host bridge, access RC and EP config space are not the same way.
Our host bridge is non ECAM only for the RC bus config space;
for any other bus underneath the root bus we support ECAM access.
hisi_pcie_common_cfg_read is used to read RC config space, only supports 32-bit config access.
hisi_pcie_common_cfg_read/hisi_pcie_common_cfg_write may change as below will be better.
/* HipXX PCIe host only supports 32-bit config access */
int hisi_pcie_common_cfg_read(void __iomem *reg_base, int where, int size,
u32 *val)
{
void __iomem *addr;
addr = reg_base + (where & ~0x3);
*val = readl(addr);
if (size <= 2)
*val = (*val >> (8 * (where & 3))) & ((1 << (size * 8)) - 1);
return PCIBIOS_SUCCESSFUL;
}
/* HipXX PCIe host only supports 32-bit config access */
int hisi_pcie_common_cfg_write(void __iomem *reg_base, int where, int size,
u32 val)
{
void __iomem *addr;
u32 mask, tmp;
addr = reg_base + (where & ~0x3);
if (size == 4) {
writel(val, addr);
return PCIBIOS_SUCCESSFUL;
} else {
mask = ~(((1 << (size * 8)) - 1) << ((where & 0x3) * 8));
}
tmp = readl(addr) & mask;
tmp |= val << ((where & 0x3) * 8);
writel(tmp, addr);
return PCIBIOS_SUCCESSFUL;
}
Thanks
Dongdong
> Arnd
>
> .
>
next prev parent reply other threads:[~2016-09-01 2:06 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-31 11:48 [RFC PATCH V2 0/3] Add ACPI support for Hisilicon PCIe Host Controller Dongdong Liu
2016-08-31 11:48 ` [RFC PATCH V2 1/3] PCI: hisi: re-architect Hip05/Hip06 controllers driver to preapare for ACPI Dongdong Liu
2016-08-31 11:45 ` Arnd Bergmann
2016-09-01 2:05 ` Dongdong Liu [this message]
2016-09-01 7:41 ` Arnd Bergmann
2016-09-01 12:44 ` Dongdong Liu
2016-09-01 14:02 ` Arnd Bergmann
2016-09-02 2:02 ` Dongdong Liu
2016-09-20 9:45 ` Gabriele Paoloni
2016-09-20 13:22 ` Arnd Bergmann
2016-08-31 11:48 ` [RFC PATCH V2 2/3] PCI: hisi: Add ECAM support for devices that are not RC Dongdong Liu
2016-08-31 11:48 ` [RFC PATCH V2 3/3] PCI/ACPI: hisi: Add ACPI support for HiSilicon SoCs Host Controllers Dongdong Liu
2016-08-31 11:48 ` Arnd Bergmann
2016-09-01 2:16 ` Dongdong Liu
2016-08-31 22:56 ` Rafael J. Wysocki
2016-09-01 3:23 ` Dongdong Liu
2016-09-01 23:38 ` Rafael J. Wysocki
2016-09-02 3:49 ` Dongdong Liu
-- strict thread matches above, loose matches on Subject: below --
2016-02-08 12:41 [RFC PATCH v2 0/3] Add ACPI support for HiSilicon PCIe " Gabriele Paoloni
2016-02-08 12:41 ` [RFC PATCH v2 1/3] PCI: hisi: re-architect Hip05/Hip06 controllers driver to preapare for ACPI Gabriele Paoloni
2016-02-08 13:50 ` Arnd Bergmann
2016-02-08 16:06 ` Gabriele Paoloni
2016-02-08 16:32 ` Arnd Bergmann
2016-02-08 16:51 ` Gabriele Paoloni
2016-02-09 16:27 ` Arnd Bergmann
2016-02-09 16:52 ` Gabriele Paoloni
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