[2/2] PCI/DPC: Use defines with register fields
Commit Message
Use defines instead of literals and replace custom masking and shifts
with FIELD_GET() where it makes sense.
While at it, group PCI_EXP_DPC_CTL RMW and pci_info() lines together
as it makes the code intent slightly easier to follow.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/pci/pcie/dpc.c | 39 ++++++++++++++++++++++++---------------
1 file changed, 24 insertions(+), 15 deletions(-)
Comments
On Fri, Oct 13, 2023 at 02:20:04PM +0300, Ilpo Järvinen wrote:
> Use defines instead of literals and replace custom masking and shifts
> with FIELD_GET() where it makes sense.
> ...
> pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
> - pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
>
> - ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
> + pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
> + ctl |= PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
> + ctl &= ~PCI_EXP_DPC_CTL_EN_NONFATAL;
This has been a little obtuse from the beginning.
The original clears bits 0, 1, 3, then sets bits 0 and 3.
The new code sets bits 0, 3, then clears bit 1.
These are equivalent, but it's definitely some work to verify it.
I think the point is to enable DPC on ERR_FATAL (but not ERR_NONFATAL)
and to enable DPC interrupts. What about something like this?
#define PCI_EXP_DPC_CTL_EN_MASK 0x0003
ctl &= ~PCI_EXP_DPC_CTL_EN_MASK;
ctl |= PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
> pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl);
> - pci_info(pdev, "enabled with IRQ %d\n", dev->irq);
>
> + pci_info(pdev, "enabled with IRQ %d\n", dev->irq);
> pci_info(pdev, "error containment capabilities: Int Msg #%d, RPExt%c PoisonedTLP%c SwTrigger%c RP PIO Log %d, DL_ActiveErr%c\n",
> cap & PCI_EXP_DPC_IRQ, FLAG(cap, PCI_EXP_DPC_CAP_RP_EXT),
> FLAG(cap, PCI_EXP_DPC_CAP_POISONED_TLP),
> --
> 2.30.2
>
On Fri, 13 Oct 2023, Bjorn Helgaas wrote:
> On Fri, Oct 13, 2023 at 02:20:04PM +0300, Ilpo Järvinen wrote:
> > Use defines instead of literals and replace custom masking and shifts
> > with FIELD_GET() where it makes sense.
> > ...
>
> > pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
> > - pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
> >
> > - ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
> > + pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
> > + ctl |= PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
> > + ctl &= ~PCI_EXP_DPC_CTL_EN_NONFATAL;
>
> This has been a little obtuse from the beginning.
>
> The original clears bits 0, 1, 3, then sets bits 0 and 3.
> The new code sets bits 0, 3, then clears bit 1.
>
> These are equivalent, but it's definitely some work to verify it.
>
> I think the point is to enable DPC on ERR_FATAL (but not ERR_NONFATAL)
> and to enable DPC interrupts. What about something like this?
> #define PCI_EXP_DPC_CTL_EN_MASK 0x0003
>
> ctl &= ~PCI_EXP_DPC_CTL_EN_MASK;
> ctl |= PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
Thanks for the suggestion, it looks cleaner, yes. I realized the bit
changes weren't as obvious as they could be but I failed to see I could
add such a combined mask to make the intent dead obvious.
With a small change replacing the 0x0003 literal with the combined defines
of the actual bits it seems very clear what's going on. I'll go for that.
I'll place my non-FIELD_GET() changes on DPC top of your
FIELD_GET/PREP()-only change so each patch can be smaller and more
focused.
@@ -9,6 +9,7 @@
#define dev_fmt(fmt) "DPC: " fmt
#include <linux/aer.h>
+#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/init.h>
@@ -202,7 +203,7 @@ static void dpc_process_rp_pio_error(struct pci_dev *pdev)
/* Get First Error Pointer */
pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &dpc_status);
- first_error = (dpc_status & 0x1f00) >> 8;
+ first_error = FIELD_GET(PCI_EXP_DPC_RP_PIO_FEP, dpc_status);
for (i = 0; i < ARRAY_SIZE(rp_pio_error_string); i++) {
if ((status & ~mask) & (1 << i))
@@ -270,20 +271,27 @@ void dpc_process_error(struct pci_dev *pdev)
pci_info(pdev, "containment event, status:%#06x source:%#06x\n",
status, source);
- reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN) >> 1;
- ext_reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT) >> 5;
+ reason = status & PCI_EXP_DPC_STATUS_TRIGGER_RSN;
+ ext_reason = status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT;
pci_warn(pdev, "%s detected\n",
- (reason == 0) ? "unmasked uncorrectable error" :
- (reason == 1) ? "ERR_NONFATAL" :
- (reason == 2) ? "ERR_FATAL" :
- (ext_reason == 0) ? "RP PIO error" :
- (ext_reason == 1) ? "software trigger" :
- "reserved error");
+ (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR) ?
+ "unmasked uncorrectable error" :
+ (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_NFE) ?
+ "ERR_NONFATAL" :
+ (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_FE) ?
+ "ERR_FATAL" :
+ (ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_RP_PIO) ?
+ "RP PIO error" :
+ (ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_SW_TRIGGER) ?
+ "software trigger" :
+ "reserved error");
/* show RP PIO error detail information */
- if (pdev->dpc_rp_extensions && reason == 3 && ext_reason == 0)
+ if (pdev->dpc_rp_extensions &&
+ reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_IN_EXT &&
+ ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_RP_PIO)
dpc_process_rp_pio_error(pdev);
- else if (reason == 0 &&
+ else if (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR &&
dpc_get_aer_uncorrect_severity(pdev, &info) &&
aer_get_device_error_info(pdev, &info)) {
aer_print_error(pdev, &info);
@@ -338,7 +346,7 @@ void pci_dpc_init(struct pci_dev *pdev)
/* Quirks may set dpc_rp_log_size if device or firmware is buggy */
if (!pdev->dpc_rp_log_size) {
pdev->dpc_rp_log_size =
- (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
+ FIELD_GET(PCI_EXP_DPC_RP_PIO_LOG_SIZE, cap);
if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
pci_err(pdev, "RP PIO log size %u is invalid\n",
pdev->dpc_rp_log_size);
@@ -368,12 +376,13 @@ static int dpc_probe(struct pcie_device *dev)
}
pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
- pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
- ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
+ pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
+ ctl |= PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
+ ctl &= ~PCI_EXP_DPC_CTL_EN_NONFATAL;
pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl);
- pci_info(pdev, "enabled with IRQ %d\n", dev->irq);
+ pci_info(pdev, "enabled with IRQ %d\n", dev->irq);
pci_info(pdev, "error containment capabilities: Int Msg #%d, RPExt%c PoisonedTLP%c SwTrigger%c RP PIO Log %d, DL_ActiveErr%c\n",
cap & PCI_EXP_DPC_IRQ, FLAG(cap, PCI_EXP_DPC_CAP_RP_EXT),
FLAG(cap, PCI_EXP_DPC_CAP_POISONED_TLP),