| Message ID | 20240313105804.100168-6-cassel@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | PCI: endpoint: set prefetchable bit for 64-bit BARs | expand |
On Wed, Mar 13, 2024 at 11:57:57AM +0100, Niklas Cassel wrote: > Simplify the loop in pci_epf_test_set_bar(). > If we allocated memory for the BAR, we need to call set_bar() for that > BAR, if we did not allocated memory for that BAR, we need to skip. > It is as simple as that. This also matches the logic in > pci_epf_test_unbind(). > > A 64-bit BAR will still only be one allocation, with the BAR succeeding > the 64-bit BAR being null. > > While at it, remove the misleading comment. > A EPC .set_bar() callback should never change the epf_bar->flags. > (E.g. to set a 64-bit BAR if we requested a 32-bit BAR.) > > A .set_bar() callback should do what we request it to do. > If it can't satisfy the request, it should return an error. > That's a valid assumption. But... > If platform has a specific requirement, e.g. that a certain BAR has to > be a 64-bit BAR, then it should specify that by setting the .only_64bit > flag for that specific BAR in epc_features->bar[], such that > pci_epf_alloc_space() will return a epf_bar with the 64-bit flag set. > (Such that .set_bar() will receive a request to set a 64-bit BAR.) > Looks like pcie-cadence-ep is setting the PCI_BASE_ADDRESS_MEM_TYPE_64 flag if the requested size is >2GB (I don't know why 2GB instead of 4GB in the first place). - Mani > Signed-off-by: Niklas Cassel <cassel@kernel.org> > --- > drivers/pci/endpoint/functions/pci-epf-test.c | 21 ++++--------------- > 1 file changed, 4 insertions(+), 17 deletions(-) > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c > index 20c79610712d..91bbfcb1b3ed 100644 > --- a/drivers/pci/endpoint/functions/pci-epf-test.c > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c > @@ -709,31 +709,18 @@ static void pci_epf_test_unbind(struct pci_epf *epf) > > static int pci_epf_test_set_bar(struct pci_epf *epf) > { > - int bar, add; > - int ret; > - struct pci_epf_bar *epf_bar; > + int bar, ret; > struct pci_epc *epc = epf->epc; > struct device *dev = &epf->dev; > struct pci_epf_test *epf_test = epf_get_drvdata(epf); > enum pci_barno test_reg_bar = epf_test->test_reg_bar; > - const struct pci_epc_features *epc_features; > - > - epc_features = epf_test->epc_features; > > - for (bar = 0; bar < PCI_STD_NUM_BARS; bar += add) { > - epf_bar = &epf->bar[bar]; > - /* > - * pci_epc_set_bar() sets PCI_BASE_ADDRESS_MEM_TYPE_64 > - * if the specific implementation required a 64-bit BAR, > - * even if we only requested a 32-bit BAR. > - */ > - add = (epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ? 2 : 1; > - > - if (epc_features->bar[bar].type == BAR_RESERVED) > + for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) { > + if (!epf_test->reg[bar]) > continue; > > ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, > - epf_bar); > + &epf->bar[bar]); > if (ret) { > pci_epf_free_space(epf, epf_test->reg[bar], bar, > PRIMARY_INTERFACE); > -- > 2.44.0 >
On Fri, Mar 15, 2024 at 11:09:03AM +0530, Manivannan Sadhasivam wrote: > On Wed, Mar 13, 2024 at 11:57:57AM +0100, Niklas Cassel wrote: > > Simplify the loop in pci_epf_test_set_bar(). > > If we allocated memory for the BAR, we need to call set_bar() for that > > BAR, if we did not allocated memory for that BAR, we need to skip. > > It is as simple as that. This also matches the logic in > > pci_epf_test_unbind(). > > > > A 64-bit BAR will still only be one allocation, with the BAR succeeding > > the 64-bit BAR being null. > > > > While at it, remove the misleading comment. > > A EPC .set_bar() callback should never change the epf_bar->flags. > > (E.g. to set a 64-bit BAR if we requested a 32-bit BAR.) > > > > A .set_bar() callback should do what we request it to do. > > If it can't satisfy the request, it should return an error. > > > > That's a valid assumption. But... > > > If platform has a specific requirement, e.g. that a certain BAR has to > > be a 64-bit BAR, then it should specify that by setting the .only_64bit > > flag for that specific BAR in epc_features->bar[], such that > > pci_epf_alloc_space() will return a epf_bar with the 64-bit flag set. > > (Such that .set_bar() will receive a request to set a 64-bit BAR.) > > > > Looks like pcie-cadence-ep is setting the PCI_BASE_ADDRESS_MEM_TYPE_64 flag if > the requested size is >2GB (I don't know why 2GB instead of 4GB in the first > place). That is dead code that will never be able to execute. Ever since commit f25b5fae29d4 ("PCI: endpoint: Setting a BAR size > 4 GB is invalid if 64-bit flag is not set") it has been impossible to get the .set_bar() callback with a BAR size > 2 GB. Yes, 2GB! The author of f25b5fae29d4 is an idiot (yes, it is me). Anyway, the code itself in that commit is doing the right thing... 2GB is the maximum size of a 32-bit BAR. So, since the the code in pcie-cadence-ep is dead code, I don't see any problem with this commit. Kind regards, Niklas > > - Mani > > > Signed-off-by: Niklas Cassel <cassel@kernel.org> > > --- > > drivers/pci/endpoint/functions/pci-epf-test.c | 21 ++++--------------- > > 1 file changed, 4 insertions(+), 17 deletions(-) > > > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c > > index 20c79610712d..91bbfcb1b3ed 100644 > > --- a/drivers/pci/endpoint/functions/pci-epf-test.c > > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c > > @@ -709,31 +709,18 @@ static void pci_epf_test_unbind(struct pci_epf *epf) > > > > static int pci_epf_test_set_bar(struct pci_epf *epf) > > { > > - int bar, add; > > - int ret; > > - struct pci_epf_bar *epf_bar; > > + int bar, ret; > > struct pci_epc *epc = epf->epc; > > struct device *dev = &epf->dev; > > struct pci_epf_test *epf_test = epf_get_drvdata(epf); > > enum pci_barno test_reg_bar = epf_test->test_reg_bar; > > - const struct pci_epc_features *epc_features; > > - > > - epc_features = epf_test->epc_features; > > > > - for (bar = 0; bar < PCI_STD_NUM_BARS; bar += add) { > > - epf_bar = &epf->bar[bar]; > > - /* > > - * pci_epc_set_bar() sets PCI_BASE_ADDRESS_MEM_TYPE_64 > > - * if the specific implementation required a 64-bit BAR, > > - * even if we only requested a 32-bit BAR. > > - */ > > - add = (epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ? 2 : 1; > > - > > - if (epc_features->bar[bar].type == BAR_RESERVED) > > + for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) { > > + if (!epf_test->reg[bar]) > > continue; > > > > ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, > > - epf_bar); > > + &epf->bar[bar]); > > if (ret) { > > pci_epf_free_space(epf, epf_test->reg[bar], bar, > > PRIMARY_INTERFACE); > > -- > > 2.44.0 > > > > -- > மணிவண்ணன் சதாசிவம்
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c index 20c79610712d..91bbfcb1b3ed 100644 --- a/drivers/pci/endpoint/functions/pci-epf-test.c +++ b/drivers/pci/endpoint/functions/pci-epf-test.c @@ -709,31 +709,18 @@ static void pci_epf_test_unbind(struct pci_epf *epf) static int pci_epf_test_set_bar(struct pci_epf *epf) { - int bar, add; - int ret; - struct pci_epf_bar *epf_bar; + int bar, ret; struct pci_epc *epc = epf->epc; struct device *dev = &epf->dev; struct pci_epf_test *epf_test = epf_get_drvdata(epf); enum pci_barno test_reg_bar = epf_test->test_reg_bar; - const struct pci_epc_features *epc_features; - - epc_features = epf_test->epc_features; - for (bar = 0; bar < PCI_STD_NUM_BARS; bar += add) { - epf_bar = &epf->bar[bar]; - /* - * pci_epc_set_bar() sets PCI_BASE_ADDRESS_MEM_TYPE_64 - * if the specific implementation required a 64-bit BAR, - * even if we only requested a 32-bit BAR. - */ - add = (epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ? 2 : 1; - - if (epc_features->bar[bar].type == BAR_RESERVED) + for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) { + if (!epf_test->reg[bar]) continue; ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, - epf_bar); + &epf->bar[bar]); if (ret) { pci_epf_free_space(epf, epf_test->reg[bar], bar, PRIMARY_INTERFACE);
Simplify the loop in pci_epf_test_set_bar(). If we allocated memory for the BAR, we need to call set_bar() for that BAR, if we did not allocated memory for that BAR, we need to skip. It is as simple as that. This also matches the logic in pci_epf_test_unbind(). A 64-bit BAR will still only be one allocation, with the BAR succeeding the 64-bit BAR being null. While at it, remove the misleading comment. A EPC .set_bar() callback should never change the epf_bar->flags. (E.g. to set a 64-bit BAR if we requested a 32-bit BAR.) A .set_bar() callback should do what we request it to do. If it can't satisfy the request, it should return an error. If platform has a specific requirement, e.g. that a certain BAR has to be a 64-bit BAR, then it should specify that by setting the .only_64bit flag for that specific BAR in epc_features->bar[], such that pci_epf_alloc_space() will return a epf_bar with the 64-bit flag set. (Such that .set_bar() will receive a request to set a 64-bit BAR.) Signed-off-by: Niklas Cassel <cassel@kernel.org> --- drivers/pci/endpoint/functions/pci-epf-test.c | 21 ++++--------------- 1 file changed, 4 insertions(+), 17 deletions(-)