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SubjectRe: [RFC PATCH 1/3] PCI: endpoint: support an alignment aware map/unmaping
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On 2023/01/18 5:41, Bjorn Helgaas wrote:
> On Fri, Jan 13, 2023 at 06:03:48PM +0900, Shunsuke Mie wrote:
>> Add an align_mem operation to the EPC ops, which function is used to
>> pci_epc_map/unmap_addr(). These change to enable mapping for any alignment
>> restriction of EPC. The map function maps an aligned memory to include a
>> requested memory region.
> I think this does two things: 1) add the .align_mem() function
> pointer, and 2) move the pci_epc_mem_alloc_addr() call into
> pci_epc_map_addr(). For 2), I would expect to see
> pci_epc_mem_alloc_addr() being *removed* from somewhere else.
>
> Anyway, both are significant and should be mentioned in the commit
> log. Possibly they could even be separate commits: move the
> alloc/free first, then add .align_mem().
I understood. I attempt to arrange commits as your mention.
>
> Another question below.
>
>> Signed-off-by: Shunsuke Mie <mie@igel.co.jp>
>> ---
>> drivers/pci/endpoint/pci-epc-core.c | 57 ++++++++++++++++++++++++-----
>> include/linux/pci-epc.h | 10 +++--
>> 2 files changed, 53 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
>> index 2542196e8c3d..60d586e05e7d 100644
>> --- a/drivers/pci/endpoint/pci-epc-core.c
>> +++ b/drivers/pci/endpoint/pci-epc-core.c
>> @@ -430,8 +430,12 @@ EXPORT_SYMBOL_GPL(pci_epc_set_msix);
>> * Invoke to unmap the CPU address from PCI address.
>> */
>> void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> - phys_addr_t phys_addr)
>> + phys_addr_t phys_addr, void __iomem *virt_addr, size_t size)
>> {
>> + u64 aligned_phys;
>> + void __iomem *aligned_virt;
>> + size_t offset;
>> +
>> if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
>> return;
>>
>> @@ -441,9 +445,22 @@ void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> if (!epc->ops->unmap_addr)
>> return;
>>
>> + if (epc->ops->align_mem) {
>> + mutex_lock(&epc->lock);
>> + aligned_phys = epc->ops->align_mem(epc, phys_addr, &size);
>> + mutex_unlock(&epc->lock);
>> + } else {
>> + aligned_phys = phys_addr;
>> + }
>> +
>> + offset = phys_addr - aligned_phys;
>> + aligned_virt = virt_addr - offset;
>> +
>> mutex_lock(&epc->lock);
>> - epc->ops->unmap_addr(epc, func_no, vfunc_no, phys_addr);
>> + epc->ops->unmap_addr(epc, func_no, vfunc_no, aligned_phys);
>> mutex_unlock(&epc->lock);
>> +
>> + pci_epc_mem_free_addr(epc, aligned_phys, aligned_virt, size);
>> }
>> EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
>>
>> @@ -458,26 +475,46 @@ EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
>> *
>> * Invoke to map CPU address with PCI address.
>> */
>> -int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> - phys_addr_t phys_addr, u64 pci_addr, size_t size)
>> +void __iomem *pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> + u64 pci_addr, phys_addr_t *phys_addr, size_t size)
>> {
>> int ret;
>> + u64 aligned_addr;
>> + size_t offset;
>> + void __iomem *virt_addr;
>>
>> if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
>> - return -EINVAL;
>> + return ERR_PTR(-EINVAL);
>>
>> if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
>> - return -EINVAL;
>> + return ERR_PTR(-EINVAL);
>>
>> if (!epc->ops->map_addr)
>> - return 0;
>> + return ERR_PTR(-ENOPTSUPP);
>> +
>> + if (epc->ops->align_mem) {
>> + mutex_lock(&epc->lock);
>> + aligned_addr = epc->ops->align_mem(epc, pci_addr, &size);
>> + mutex_unlock(&epc->lock);
>> + } else {
>> + aligned_addr = pci_addr;
>> + }
>> +
>> + offset = pci_addr - aligned_addr;
>> +
>> + virt_addr = pci_epc_mem_alloc_addr(epc, phys_addr, size);
>> + if (!virt_addr)
>> + return ERR_PTR(-ENOMEM);
>>
>> mutex_lock(&epc->lock);
>> - ret = epc->ops->map_addr(epc, func_no, vfunc_no, phys_addr, pci_addr,
>> - size);
>> + ret = epc->ops->map_addr(epc, func_no, vfunc_no, *phys_addr, aligned_addr, size);
>> mutex_unlock(&epc->lock);
>> + if (ret)
>> + return ERR_PTR(ret);
>>
>> - return ret;
>> + *phys_addr += offset;
>> +
>> + return virt_addr + offset;
>> }
>> EXPORT_SYMBOL_GPL(pci_epc_map_addr);
>>
>> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
>> index a48778e1a4ee..8f29161bce80 100644
>> --- a/include/linux/pci-epc.h
>> +++ b/include/linux/pci-epc.h
>> @@ -84,6 +84,7 @@ struct pci_epc_ops {
>> phys_addr_t phys_addr, u8 interrupt_num,
>> u32 entry_size, u32 *msi_data,
>> u32 *msi_addr_offset);
>> + u64 (*align_mem)(struct pci_epc *epc, u64 addr, size_t *size);
> Is there a requirement for multiple implementations of .align_mem()?
> There's only one implementation in this series
> (dw_pcie_ep_align_mem()), and it only needs pci->region_align. That
> *value* might be DWC-specific, but the concept really isn't, so maybe
> there could be a generic function that uses the device-specific value.

That is the correct way, but some handlers require different implementation.

Sorry, this patch could have been misleading. it is my fault. I'll add
the other

handlers to a next version.

>
>> int (*start)(struct pci_epc *epc);
>> void (*stop)(struct pci_epc *epc);
>> const struct pci_epc_features* (*get_features)(struct pci_epc *epc,
>> @@ -218,11 +219,12 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> struct pci_epf_bar *epf_bar);
>> void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> struct pci_epf_bar *epf_bar);
>> -int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> - phys_addr_t phys_addr,
>> - u64 pci_addr, size_t size);
>> +void __iomem *pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> + u64 pci_addr, phys_addr_t *phys_addr,
>> + size_t size);
>> void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> - phys_addr_t phys_addr);
>> + phys_addr_t phys_addr, void __iomem *virt_addr,
>> + size_t size);
>> int pci_epc_set_msi(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> u8 interrupts);
>> int pci_epc_get_msi(struct pci_epc *epc, u8 func_no, u8 vfunc_no);
>> --
>> 2.25.1
>>
Best,

Shunsuke

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