[PATCH 06/14] pci: define some command constants

[David Marchand]

On Thu, Aug 3, 2023 at 1:51 PM David Marchand <david.marchand at redhat.com> wrote:
>
> On Thu, Aug 3, 2023 at 11:58 AM Bruce Richardson
> <bruce.richardson at intel.com> wrote:
> >
> > On Thu, Aug 03, 2023 at 09:50:29AM +0200, David Marchand wrote:
> > > Define some PCI command constants and use them in existing drivers.
> > >
> > > Signed-off-by: David Marchand <david.marchand at redhat.com>
> > > ---
> >
> > For the idea, all good, but for the implementation, one comment inline
> > below.
> >
> > With the below reworked:
> >
> > Acked-by: Bruce Richardson <bruce.richardson at intel.com>
> >
> > >  drivers/bus/pci/linux/pci_vfio.c  | 8 ++++----
> > >  drivers/event/dlb2/pf/dlb2_main.c | 8 +++-----
> > >  lib/pci/rte_pci.h                 | 4 +++-
> > >  3 files changed, 10 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/drivers/bus/pci/linux/pci_vfio.c b/drivers/bus/pci/linux/pci_vfio.c
> > > index 6d13cafdcf..f96b3ce7fb 100644
> > > --- a/drivers/bus/pci/linux/pci_vfio.c
> > > +++ b/drivers/bus/pci/linux/pci_vfio.c
> > > @@ -156,18 +156,18 @@ pci_vfio_enable_bus_memory(struct rte_pci_device *dev, int dev_fd)
> > >               return -1;
> > >       }
> > >
> > > -     ret = pread64(dev_fd, &cmd, sizeof(cmd), offset + PCI_COMMAND);
> > > +     ret = pread64(dev_fd, &cmd, sizeof(cmd), offset + RTE_PCI_COMMAND);
> > >
> > >       if (ret != sizeof(cmd)) {
> > >               RTE_LOG(ERR, EAL, "Cannot read command from PCI config space!\n");
> > >               return -1;
> > >       }
> > >
> > > -     if (cmd & PCI_COMMAND_MEMORY)
> > > +     if (cmd & RTE_PCI_COMMAND_MEMORY)
> > >               return 0;
> > >
> > > -     cmd |= PCI_COMMAND_MEMORY;
> > > -     ret = pwrite64(dev_fd, &cmd, sizeof(cmd), offset + PCI_COMMAND);
> > > +     cmd |= RTE_PCI_COMMAND_MEMORY;
> > > +     ret = pwrite64(dev_fd, &cmd, sizeof(cmd), offset + RTE_PCI_COMMAND);
> > >
> > >       if (ret != sizeof(cmd)) {
> > >               RTE_LOG(ERR, EAL, "Cannot write command to PCI config space!\n");
> > > diff --git a/drivers/event/dlb2/pf/dlb2_main.c b/drivers/event/dlb2/pf/dlb2_main.c
> > > index c6606a9bee..6dbaa2ff97 100644
> > > --- a/drivers/event/dlb2/pf/dlb2_main.c
> > > +++ b/drivers/event/dlb2/pf/dlb2_main.c
> > > @@ -33,7 +33,6 @@
> > >  #define DLB2_PCI_EXP_DEVCTL2 40
> > >  #define DLB2_PCI_LNKCTL2 48
> > >  #define DLB2_PCI_SLTCTL2 56
> > > -#define DLB2_PCI_CMD 4
> > >  #define DLB2_PCI_EXP_DEVSTA 10
> > >  #define DLB2_PCI_EXP_DEVSTA_TRPND 0x20
> > >  #define DLB2_PCI_EXP_DEVCTL_BCR_FLR 0x8000
> > > @@ -47,7 +46,6 @@
> > >  #define DLB2_PCI_ERR_ROOT_STATUS         0x30
> > >  #define DLB2_PCI_ERR_COR_STATUS          0x10
> > >  #define DLB2_PCI_ERR_UNCOR_STATUS        0x4
> > > -#define DLB2_PCI_COMMAND_INTX_DISABLE    0x400
> > >  #define DLB2_PCI_ACS_CAP                 0x4
> > >  #define DLB2_PCI_ACS_CTRL                0x6
> > >  #define DLB2_PCI_ACS_SV                  0x1
> > > @@ -286,7 +284,7 @@ dlb2_pf_reset(struct dlb2_dev *dlb2_dev)
> > >
> > >       /* clear the PCI command register before issuing the FLR */
> > >
> > > -     off = DLB2_PCI_CMD;
> > > +     off = RTE_PCI_COMMAND;
> > >       cmd = 0;
> > >       if (rte_pci_write_config(pdev, &cmd, 2, off) != 2) {
> > >               DLB2_LOG_ERR("[%s()] failed to write the pci command\n",
> > > @@ -468,9 +466,9 @@ dlb2_pf_reset(struct dlb2_dev *dlb2_dev)
> > >               }
> > >       }
> > >
> > > -     off = DLB2_PCI_CMD;
> > > +     off = RTE_PCI_COMMAND;
> > >       if (rte_pci_read_config(pdev, &cmd, 2, off) == 2) {
> > > -             cmd &= ~DLB2_PCI_COMMAND_INTX_DISABLE;
> > > +             cmd &= ~RTE_PCI_COMMAND_INTX_DISABLE;
> > >               if (rte_pci_write_config(pdev, &cmd, 2, off) != 2) {
> > >                       DLB2_LOG_ERR("[%s()] failed to write the pci command\n",
> > >                              __func__);
> > > diff --git a/lib/pci/rte_pci.h b/lib/pci/rte_pci.h
> > > index a055a28592..bf2b2639f4 100644
> > > --- a/lib/pci/rte_pci.h
> > > +++ b/lib/pci/rte_pci.h
> > > @@ -32,10 +32,12 @@ extern "C" {
> > >
> > >  #define RTE_PCI_VENDOR_ID    0x00    /* 16 bits */
> > >  #define RTE_PCI_DEVICE_ID    0x02    /* 16 bits */
> > > -#define RTE_PCI_COMMAND              0x04    /* 16 bits */
> > >
> > >  /* PCI Command Register */
> > > +#define RTE_PCI_COMMAND              0x04    /* 16 bits */
> > > +#define RTE_PCI_COMMAND_MEMORY       0x2     /* Enable response in Memory space */
> > >  #define RTE_PCI_COMMAND_MASTER       0x4     /* Bus Master Enable */
> > > +#define RTE_PCI_COMMAND_INTX_DISABLE 0x400 /* INTx Emulation Disable */
> > >
> >
> > It's weird here to have two defines in the same block with the same value -
> > even if one is 0x04 and the other is 0x4. That implies that the two values
> > don't belong in the same block of defines.
> >
> > Question - would enums make sense for defining any of these? It allows
> > the groups to be named?
>
> That's something I will look into, or at least better organise the defines..

At least, using enum would be a (minor) change in the API, as macros
were used so far and maybe some users were relying on them (#ifdef /
#ifndef).

I relooked at linux/pci_regs.h which organises those defines a bit as
I did, but with some kind of indentation (double space) to separate
the first offset of a block and the rest of the defines related to
said block of defines/registers.
Example:
#define PCI_COMMAND             0x04    /* 16 bits */
#define  PCI_COMMAND_IO         0x1     /* Enable response in I/O space */
#define  PCI_COMMAND_MEMORY     0x2     /* Enable response in Memory space */
#define  PCI_COMMAND_MASTER     0x4     /* Enable bus mastering */
#define  PCI_COMMAND_SPECIAL    0x8     /* Enable response to special cycles */


-- 
David Marchand