Re: [RFC 01/10] PCI: dwc: Add MSI-X callbacks handler

From: Gustavo Pimentel
Date: Tue Apr 24 2018 - 07:45:03 EST


On 24/04/2018 10:15, Alan Douglas wrote:
> Hi,
>
> On 10 April 2018 18:15 Gustavo Pimentel wrote:
>> Changes the pcie_raise_irq function signature, namely the interrupt_num
>> variable type from u8 to u16 to accommodate the MSI-X maximum interrupts
>> of 2048.
>>
>> Implements a PCIe config space capability iterator function to search and save
>> the MSI and MSI-X pointers. With this method the code becomes more
>> generic and flexible.
>>
>> Implements MSI-X set/get functions for sysfs interface in order to change the
>> EP entries number.
>>
>> Implements EP MSI-X interface for triggering interruptions.
>>
>> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@xxxxxxxxxxxx>
>> ---
>> drivers/pci/dwc/pci-dra7xx.c | 2 +-
>> drivers/pci/dwc/pcie-artpec6.c | 2 +-
>> drivers/pci/dwc/pcie-designware-ep.c | 145
>> ++++++++++++++++++++++++++++++++-
>> drivers/pci/dwc/pcie-designware-plat.c | 6 +-
>> drivers/pci/dwc/pcie-designware.h | 23 +++++-
>> 5 files changed, 173 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/pci/dwc/pci-dra7xx.c b/drivers/pci/dwc/pci-dra7xx.c index
>> ed8558d..5265725 100644
>> --- a/drivers/pci/dwc/pci-dra7xx.c
>> +++ b/drivers/pci/dwc/pci-dra7xx.c
>> @@ -369,7 +369,7 @@ static void dra7xx_pcie_raise_msi_irq(struct
>> dra7xx_pcie *dra7xx, }
>>
>> static int dra7xx_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
>> - enum pci_epc_irq_type type, u8
>> interrupt_num)
>> + enum pci_epc_irq_type type, u16
>> interrupt_num)
>> {
>> struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> struct dra7xx_pcie *dra7xx = to_dra7xx_pcie(pci); diff --git
>> a/drivers/pci/dwc/pcie-artpec6.c b/drivers/pci/dwc/pcie-artpec6.c index
>> e66cede..96dc259 100644
>> --- a/drivers/pci/dwc/pcie-artpec6.c
>> +++ b/drivers/pci/dwc/pcie-artpec6.c
>> @@ -428,7 +428,7 @@ static void artpec6_pcie_ep_init(struct dw_pcie_ep
>> *ep) }
>>
>> static int artpec6_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
>> - enum pci_epc_irq_type type, u8
>> interrupt_num)
>> + enum pci_epc_irq_type type, u16
>> interrupt_num)
>> {
>> struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>>
>> diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-
>> designware-ep.c
>> index 15b22a6..874d4c2 100644
>> --- a/drivers/pci/dwc/pcie-designware-ep.c
>> +++ b/drivers/pci/dwc/pcie-designware-ep.c
>> @@ -40,6 +40,44 @@ void dw_pcie_ep_reset_bar(struct dw_pcie *pci,
>> enum pci_barno bar)
>> __dw_pcie_ep_reset_bar(pci, bar, 0);
>> }
>>
>> +void dw_pcie_ep_find_cap_addr(struct dw_pcie_ep *ep) {
>> + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> + u8 next_ptr, curr_ptr, cap_id;
>> + u16 reg;
>> +
>> + memset(&ep->cap_addr, 0, sizeof(ep->cap_addr));
>> +
>> + reg = dw_pcie_readw_dbi(pci, PCI_STATUS);
>> + if (!(reg & PCI_STATUS_CAP_LIST))
>> + return;
>> +
>> + reg = dw_pcie_readw_dbi(pci, PCI_CAPABILITY_LIST);
>> + next_ptr = (reg & 0x00ff);
>> + if (!next_ptr)
>> + return;
>> +
>> + reg = dw_pcie_readw_dbi(pci, next_ptr);
>> + curr_ptr = next_ptr;
>> + next_ptr = (reg & 0xff00) >> 8;
>> + cap_id = (reg & 0x00ff);
>> +
>> + while (next_ptr && (cap_id <= PCI_CAP_ID_MAX)) {
>> + switch (cap_id) {
>> + case PCI_CAP_ID_MSI:
>> + ep->cap_addr.msi_addr = curr_ptr;
>> + break;
>> + case PCI_CAP_ID_MSIX:
>> + ep->cap_addr.msix_addr = curr_ptr;
>> + break;
>> + }
>> + reg = dw_pcie_readw_dbi(pci, next_ptr);
>> + curr_ptr = next_ptr;
>> + next_ptr = (reg & 0xff00) >> 8;
>> + cap_id = (reg & 0x00ff);
>> + }
>> +}
>> +
>> static int dw_pcie_ep_write_header(struct pci_epc *epc, u8 func_no,
>> struct pci_epf_header *hdr)
>> {
>> @@ -241,8 +279,47 @@ static int dw_pcie_ep_set_msi(struct pci_epc *epc,
>> u8 func_no, u8 encode_int)
>> return 0;
>> }
>>
>> +static int dw_pcie_ep_get_msix(struct pci_epc *epc, u8 func_no) {
>> + struct dw_pcie_ep *ep = epc_get_drvdata(epc);
>> + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> + u32 val, reg;
>> +
>> + if (ep->cap_addr.msix_addr == 0)
>> + return 0;
>> +
>> + reg = ep->cap_addr.msix_addr + PCI_MSIX_FLAGS;
>> + val = dw_pcie_readw_dbi(pci, reg);
>> + if (!(val & PCI_MSIX_FLAGS_ENABLE))
>> + return -EINVAL;
>> +
>> + val &= PCI_MSIX_FLAGS_QSIZE;
>> +
>> + return val;
>> +}
>> +
>> +static int dw_pcie_ep_set_msix(struct pci_epc *epc, u8 func_no, u16
>> +interrupts) {
>> + struct dw_pcie_ep *ep = epc_get_drvdata(epc);
>> + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> + u32 val, reg;
>> +
>> + if (ep->cap_addr.msix_addr == 0)
>> + return 0;
>> +
>> + reg = ep->cap_addr.msix_addr + PCI_MSIX_FLAGS;
>> + val = dw_pcie_readw_dbi(pci, reg);
>> + val &= ~PCI_MSIX_FLAGS_QSIZE;
>> + val |= interrupts;
>> + dw_pcie_dbi_ro_wr_en(pci);
>> + dw_pcie_writew_dbi(pci, reg, val);
>> + dw_pcie_dbi_ro_wr_dis(pci);
>> +
>> + return 0;
>> +}
>> +
>> static int dw_pcie_ep_raise_irq(struct pci_epc *epc, u8 func_no,
>> - enum pci_epc_irq_type type, u8
>> interrupt_num)
>> + enum pci_epc_irq_type type, u16
>> interrupt_num)
>> {
>> struct dw_pcie_ep *ep = epc_get_drvdata(epc);
>>
>> @@ -282,6 +359,8 @@ static const struct pci_epc_ops epc_ops = {
>> .unmap_addr = dw_pcie_ep_unmap_addr,
>> .set_msi = dw_pcie_ep_set_msi,
>> .get_msi = dw_pcie_ep_get_msi,
>> + .set_msix = dw_pcie_ep_set_msix,
>> + .get_msix = dw_pcie_ep_get_msix,
>> .raise_irq = dw_pcie_ep_raise_irq,
>> .start = dw_pcie_ep_start,
>> .stop = dw_pcie_ep_stop,
>> @@ -322,6 +401,60 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep
>> *ep, u8 func_no,
>> return 0;
>> }
>>
>> +int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>> + u16 interrupt_num)
>> +{
>> + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> + struct pci_epc *epc = ep->epc;
>> + u16 tbl_offset, bir;
>> + u32 bar_addr_upper, bar_addr_lower;
>> + u32 msg_addr_upper, msg_addr_lower;
>> + u32 reg, msg_data;
>> + u64 tbl_addr, msg_addr, reg_u64;
>> + void __iomem *msix_tbl;
>> + int ret;
>> +
>> + reg = ep->cap_addr.msix_addr + PCI_MSIX_TABLE;
>> + tbl_offset = dw_pcie_readl_dbi(pci, reg);
>> + bir = (tbl_offset & PCI_MSIX_TABLE_BIR);
>> + tbl_offset &= PCI_MSIX_TABLE_OFFSET;
>> + tbl_offset >>= 3;
>> +
>> + reg = PCI_BASE_ADDRESS_0 + (4 * bir);
>> + bar_addr_lower = dw_pcie_readl_dbi(pci, reg);
>> + reg_u64 = (bar_addr_lower & PCI_BASE_ADDRESS_MEM_TYPE_MASK);
>> + if (reg_u64 == PCI_BASE_ADDRESS_MEM_TYPE_64)
>> + bar_addr_upper = dw_pcie_readl_dbi(pci, reg + 4);
>> + else
>> + bar_addr_upper = 0;
>> +
>> + tbl_addr = ((u64) bar_addr_upper) << 32 | bar_addr_lower;
>> + tbl_addr += (tbl_offset + ((interrupt_num - 1) * PCI_MSIX_ENTRY_SIZE));
>> + tbl_addr &= PCI_BASE_ADDRESS_MEM_MASK;
>> +
>> + msix_tbl = ioremap_nocache(ep->phys_base + tbl_addr, ep->addr_size);
>> + if (!msix_tbl)
>> + return -EINVAL;
>> +
> I think you need to check the mask bit in vector control for the requested IRQ.
> You could set the pending bit if masked, but would then need some output
> signal to inform when the mask bit is cleared (or poll it) so the message can be sent
> later.

I have to analyze this careful and with detail to provide you a valid and good
feedback as soon as possible.

>
> Also, do you need to check PCI_MSIX_FLAGS_ENABLE here as well, or is it checked earlier?

I applied the same logic for MSI-X already implemented before for the MSI.

Before calling the pci_epc_raise_irq(), the number of interrupts is checked by
calling the pci_epc_get_msi() first, which leads to one of
dw_pcie_ep_get_msi()/cdns_pcie_ep_get_msi().

>From what I could see the PCI_MSI_FLAGS_ENABLE/PCI_MSIX_FLAGS_ENABLE flags are
check on the dw_pcie_ep_get_msi()/dw_pcie_ep_get_msix() funcitons, the same
logic is applied on cdns_pcie_ep_get_msi().

>
> Regards,
> Alan
>