[PATCH V8 0/5] PCI: Loongson pci improvements and quirks

[PATCH V8 0/5] PCI: Loongson pci improvements and quirks

[Huacai Chen]

This patchset improves Loongson PCI controller driver and resolves some
problems: LS2K/LS7A's PCI config space supports 1/2/4-bytes access, so
the first patch use pci_generic_config_read()/pci_generic_config_write()
for them; the second patch add ACPI init support which will be used by
LoongArch; the third patch improves the mrrs quirk for LS7A chipset; The
fourth patch add a new quirk for LS7A chipset to avoid poweroff/reboot
failure, and the fifth patch add a new quirk for LS7A chipset to fix the
multifunction devices' irq pin mappings.

V1 -> V2:
1, Rework the 4th patch;
2, Improve commit messages;
3, Remove the last patch since there is better solutions.

V2 -> V3:
1, Add more affected device ids for the 4th patch;
2, Improve commit messages to describe root causes.

V3 -> V4:
1, Rework the MRRS quirk patch;
2, Improve commit messages to describe root causes, again.

V4 -> V5:
1, Improve the MRRS quirk patch;
2, Change the order of 2nd and 3rd patch;
3, Improve commit messages to describe root causes, again.

V5 -> V6:
1, Rework the 1st patch;
2, Adjust the order of the series.

V6 -> V7:
1, Use correct pci config access operations;
2, Add ACPI init support for LoongArch;
3, Don't move to quirks.c since the driver has ACPI support;
4, Some other minor improvements.

V7 -> V8:
1, Use CFG1 method for LS2K/LS7A pci config;

Huacai Chen, Tiezhu Yang and Jianmin Lv(5):
 PCI: loongson: Use correct pci config access operations.
 PCI: loongson: Add ACPI init support.
 PCI: Improve the MRRS quirk for LS7A.
 PCI: Add quirk for LS7A to avoid reboot failure.
 PCI: Add quirk for multifunction devices of LS7A.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn> 
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 drivers/acpi/pci_mcfg.c               |  13 +++
 drivers/pci/controller/Kconfig        |   2 +-
 drivers/pci/controller/pci-loongson.c | 184 ++++++++++++++++++++++++++--------
 drivers/pci/pci.c                     |   6 ++
 drivers/pci/pcie/portdrv_core.c       |   6 +-
 include/linux/pci-ecam.h              |   1 +
 include/linux/pci.h                   |   2 +
 7 files changed, 169 insertions(+), 45 deletions(-)
--
2.27.0

[PATCH V8 1/5] PCI: loongson: Use correct pci config access operations

[Huacai Chen]

LS2K/LS7A support 8/16/32-bits pci config access operations via CFG1, so
we can disable CFG0 for them and safely use pci_generic_config_read()/
pci_generic_config_write() instead of pci_generic_config_read32()/pci_
generic_config_write32().

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 drivers/pci/controller/pci-loongson.c | 36 +++++++++++++++++----------
 1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
index 48169b1e3817..b2c81c762599 100644
--- a/drivers/pci/controller/pci-loongson.c
+++ b/drivers/pci/controller/pci-loongson.c
@@ -159,8 +159,15 @@ static int loongson_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
 	return val;
 }
 
-/* H/w only accept 32-bit PCI operations */
+/* LS2K/LS7A accept 8/16/32-bit PCI operations */
 static struct pci_ops loongson_pci_ops = {
+	.map_bus = pci_loongson_map_bus,
+	.read	= pci_generic_config_read,
+	.write	= pci_generic_config_write,
+};
+
+/* RS780/SR5690 only accept 32-bit PCI operations */
+static struct pci_ops loongson_pci_ops32 = {
 	.map_bus = pci_loongson_map_bus,
 	.read	= pci_generic_config_read32,
 	.write	= pci_generic_config_write32,
@@ -168,9 +175,9 @@ static struct pci_ops loongson_pci_ops = {
 
 static const struct of_device_id loongson_pci_of_match[] = {
 	{ .compatible = "loongson,ls2k-pci",
-		.data = (void *)(FLAG_CFG0 | FLAG_CFG1 | FLAG_DEV_FIX), },
+		.data = (void *)(FLAG_CFG1 | FLAG_DEV_FIX), },
 	{ .compatible = "loongson,ls7a-pci",
-		.data = (void *)(FLAG_CFG0 | FLAG_CFG1 | FLAG_DEV_FIX), },
+		.data = (void *)(FLAG_CFG1 | FLAG_DEV_FIX), },
 	{ .compatible = "loongson,rs780e-pci",
 		.data = (void *)(FLAG_CFG0), },
 	{}
@@ -195,17 +202,17 @@ static int loongson_pci_probe(struct platform_device *pdev)
 	priv->pdev = pdev;
 	priv->flags = (unsigned long)of_device_get_match_data(dev);
 
-	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!regs) {
-		dev_err(dev, "missing mem resources for cfg0\n");
-		return -EINVAL;
+	if (priv->flags & FLAG_CFG0) {
+		regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+		if (!regs)
+			dev_err(dev, "missing mem resources for cfg0\n");
+		else {
+			priv->cfg0_base = devm_pci_remap_cfg_resource(dev, regs);
+			if (IS_ERR(priv->cfg0_base))
+				return PTR_ERR(priv->cfg0_base);
+		}
 	}
 
-	priv->cfg0_base = devm_pci_remap_cfg_resource(dev, regs);
-	if (IS_ERR(priv->cfg0_base))
-		return PTR_ERR(priv->cfg0_base);
-
-	/* CFG1 is optional */
 	if (priv->flags & FLAG_CFG1) {
 		regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 		if (!regs)
@@ -218,8 +225,11 @@ static int loongson_pci_probe(struct platform_device *pdev)
 	}
 
 	bridge->sysdata = priv;
-	bridge->ops = &loongson_pci_ops;
 	bridge->map_irq = loongson_map_irq;
+	if (!of_device_is_compatible(node, "loongson,rs780e-pci"))
+		bridge->ops = &loongson_pci_ops;
+	else
+		bridge->ops = &loongson_pci_ops32;
 
 	return pci_host_probe(bridge);
 }
-- 
2.27.0

Re: [PATCH V8 1/5] PCI: loongson: Use correct pci config access operations

[Bjorn Helgaas]

Things like "Use correct ..." in subject lines are useless.  *Every*
patch should do the "proper" or "correct" thing, so it should go
without saying.  Repeating it doesn't make it more true.

This doesn't apply to *all* loongson devices, so it would be useful to
hint at the devices it *does* apply to.

Maybe something like:

  PCI: loongson: Use generic 8/16/32-bit config ops on LS2K/LS7A

On Wed, Aug 25, 2021 at 02:07:20PM +0800, Huacai Chen wrote:
> LS2K/LS7A support 8/16/32-bits pci config access operations via CFG1, so
> we can disable CFG0 for them and safely use pci_generic_config_read()/
> pci_generic_config_write() instead of pci_generic_config_read32()/pci_
> generic_config_write32().

s/pci/PCI/

> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> ---
>  drivers/pci/controller/pci-loongson.c | 36 +++++++++++++++++----------
>  1 file changed, 23 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
> index 48169b1e3817..b2c81c762599 100644
> --- a/drivers/pci/controller/pci-loongson.c
> +++ b/drivers/pci/controller/pci-loongson.c
> @@ -159,8 +159,15 @@ static int loongson_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
>  	return val;
>  }
>  
> -/* H/w only accept 32-bit PCI operations */
> +/* LS2K/LS7A accept 8/16/32-bit PCI operations */

*config* operations

>  static struct pci_ops loongson_pci_ops = {
> +	.map_bus = pci_loongson_map_bus,
> +	.read	= pci_generic_config_read,
> +	.write	= pci_generic_config_write,
> +};
> +
> +/* RS780/SR5690 only accept 32-bit PCI operations */
> +static struct pci_ops loongson_pci_ops32 = {
>  	.map_bus = pci_loongson_map_bus,
>  	.read	= pci_generic_config_read32,
>  	.write	= pci_generic_config_write32,
> @@ -168,9 +175,9 @@ static struct pci_ops loongson_pci_ops = {
>  
>  static const struct of_device_id loongson_pci_of_match[] = {
>  	{ .compatible = "loongson,ls2k-pci",
> -		.data = (void *)(FLAG_CFG0 | FLAG_CFG1 | FLAG_DEV_FIX), },
> +		.data = (void *)(FLAG_CFG1 | FLAG_DEV_FIX), },
>  	{ .compatible = "loongson,ls7a-pci",
> -		.data = (void *)(FLAG_CFG0 | FLAG_CFG1 | FLAG_DEV_FIX), },
> +		.data = (void *)(FLAG_CFG1 | FLAG_DEV_FIX), },
>  	{ .compatible = "loongson,rs780e-pci",
>  		.data = (void *)(FLAG_CFG0), },

It'd be nice if you used the same strategy as most other drivers,
e.g., ".data = &loongson_ls2k_data" or similar.

>  	{}
> @@ -195,17 +202,17 @@ static int loongson_pci_probe(struct platform_device *pdev)
>  	priv->pdev = pdev;
>  	priv->flags = (unsigned long)of_device_get_match_data(dev);
>  
> -	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -	if (!regs) {
> -		dev_err(dev, "missing mem resources for cfg0\n");
> -		return -EINVAL;
> +	if (priv->flags & FLAG_CFG0) {
> +		regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +		if (!regs)
> +			dev_err(dev, "missing mem resources for cfg0\n");
> +		else {
> +			priv->cfg0_base = devm_pci_remap_cfg_resource(dev, regs);
> +			if (IS_ERR(priv->cfg0_base))
> +				return PTR_ERR(priv->cfg0_base);
> +		}
>  	}
>  
> -	priv->cfg0_base = devm_pci_remap_cfg_resource(dev, regs);
> -	if (IS_ERR(priv->cfg0_base))
> -		return PTR_ERR(priv->cfg0_base);
> -
> -	/* CFG1 is optional */
>  	if (priv->flags & FLAG_CFG1) {
>  		regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
>  		if (!regs)
> @@ -218,8 +225,11 @@ static int loongson_pci_probe(struct platform_device *pdev)
>  	}
>  
>  	bridge->sysdata = priv;
> -	bridge->ops = &loongson_pci_ops;
>  	bridge->map_irq = loongson_map_irq;
> +	if (!of_device_is_compatible(node, "loongson,rs780e-pci"))

You already called of_device_get_match_data() above, which does
essentially the same work as of_device_is_compatible().

> +		bridge->ops = &loongson_pci_ops;
> +	else
> +		bridge->ops = &loongson_pci_ops32;
>  
>  	return pci_host_probe(bridge);
>  }
> -- 
> 2.27.0
> 

Re: [PATCH V8 1/5] PCI: loongson: Use correct pci config access operations

[Huacai Chen]

Hi, Bjorn,

On Thu, Aug 26, 2021 at 1:32 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> Things like "Use correct ..." in subject lines are useless.  *Every*
> patch should do the "proper" or "correct" thing, so it should go
> without saying.  Repeating it doesn't make it more true.
>
> This doesn't apply to *all* loongson devices, so it would be useful to
> hint at the devices it *does* apply to.
>
> Maybe something like:
>
>   PCI: loongson: Use generic 8/16/32-bit config ops on LS2K/LS7A
>
> On Wed, Aug 25, 2021 at 02:07:20PM +0800, Huacai Chen wrote:
> > LS2K/LS7A support 8/16/32-bits pci config access operations via CFG1, so
> > we can disable CFG0 for them and safely use pci_generic_config_read()/
> > pci_generic_config_write() instead of pci_generic_config_read32()/pci_
> > generic_config_write32().
>
> s/pci/PCI/
>
> > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> > ---
> >  drivers/pci/controller/pci-loongson.c | 36 +++++++++++++++++----------
> >  1 file changed, 23 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
> > index 48169b1e3817..b2c81c762599 100644
> > --- a/drivers/pci/controller/pci-loongson.c
> > +++ b/drivers/pci/controller/pci-loongson.c
> > @@ -159,8 +159,15 @@ static int loongson_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
> >       return val;
> >  }
> >
> > -/* H/w only accept 32-bit PCI operations */
> > +/* LS2K/LS7A accept 8/16/32-bit PCI operations */
>
> *config* operations
>
> >  static struct pci_ops loongson_pci_ops = {
> > +     .map_bus = pci_loongson_map_bus,
> > +     .read   = pci_generic_config_read,
> > +     .write  = pci_generic_config_write,
> > +};
> > +
> > +/* RS780/SR5690 only accept 32-bit PCI operations */
> > +static struct pci_ops loongson_pci_ops32 = {
> >       .map_bus = pci_loongson_map_bus,
> >       .read   = pci_generic_config_read32,
> >       .write  = pci_generic_config_write32,
> > @@ -168,9 +175,9 @@ static struct pci_ops loongson_pci_ops = {
> >
> >  static const struct of_device_id loongson_pci_of_match[] = {
> >       { .compatible = "loongson,ls2k-pci",
> > -             .data = (void *)(FLAG_CFG0 | FLAG_CFG1 | FLAG_DEV_FIX), },
> > +             .data = (void *)(FLAG_CFG1 | FLAG_DEV_FIX), },
> >       { .compatible = "loongson,ls7a-pci",
> > -             .data = (void *)(FLAG_CFG0 | FLAG_CFG1 | FLAG_DEV_FIX), },
> > +             .data = (void *)(FLAG_CFG1 | FLAG_DEV_FIX), },
> >       { .compatible = "loongson,rs780e-pci",
> >               .data = (void *)(FLAG_CFG0), },
>
> It'd be nice if you used the same strategy as most other drivers,
> e.g., ".data = &loongson_ls2k_data" or similar.
>
> >       {}
> > @@ -195,17 +202,17 @@ static int loongson_pci_probe(struct platform_device *pdev)
> >       priv->pdev = pdev;
> >       priv->flags = (unsigned long)of_device_get_match_data(dev);
> >
> > -     regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > -     if (!regs) {
> > -             dev_err(dev, "missing mem resources for cfg0\n");
> > -             return -EINVAL;
> > +     if (priv->flags & FLAG_CFG0) {
> > +             regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +             if (!regs)
> > +                     dev_err(dev, "missing mem resources for cfg0\n");
> > +             else {
> > +                     priv->cfg0_base = devm_pci_remap_cfg_resource(dev, regs);
> > +                     if (IS_ERR(priv->cfg0_base))
> > +                             return PTR_ERR(priv->cfg0_base);
> > +             }
> >       }
> >
> > -     priv->cfg0_base = devm_pci_remap_cfg_resource(dev, regs);
> > -     if (IS_ERR(priv->cfg0_base))
> > -             return PTR_ERR(priv->cfg0_base);
> > -
> > -     /* CFG1 is optional */
> >       if (priv->flags & FLAG_CFG1) {
> >               regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> >               if (!regs)
> > @@ -218,8 +225,11 @@ static int loongson_pci_probe(struct platform_device *pdev)
> >       }
> >
> >       bridge->sysdata = priv;
> > -     bridge->ops = &loongson_pci_ops;
> >       bridge->map_irq = loongson_map_irq;
> > +     if (!of_device_is_compatible(node, "loongson,rs780e-pci"))
>
> You already called of_device_get_match_data() above, which does
> essentially the same work as of_device_is_compatible().
OK, thanks, I will update this patch.

Huacai
>
> > +             bridge->ops = &loongson_pci_ops;
> > +     else
> > +             bridge->ops = &loongson_pci_ops32;
> >
> >       return pci_host_probe(bridge);
> >  }
> > --
> > 2.27.0
> >

[PATCH V8 2/5] PCI: loongson: Add ACPI init support

[Huacai Chen]

Loongson PCH (LS7A chipset) will be used by both MIPS-based and
LoongArch-based Loongson processors. MIPS-based Loongson uses FDT
while LoongArch-base Loongson uses ACPI, this patch add ACPI init
support for the driver in drivers/pci/controller/pci-loongson.c
because it is currently FDT-only.

LoongArch is a new RISC ISA, mainline support will come soon, and
documentations are here (in translation):

https://github.com/loongson/LoongArch-Documentation

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 drivers/acpi/pci_mcfg.c               | 13 +++++++
 drivers/pci/controller/Kconfig        |  2 +-
 drivers/pci/controller/pci-loongson.c | 54 ++++++++++++++++++++++++++-
 include/linux/pci-ecam.h              |  1 +
 4 files changed, 67 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
index 53cab975f612..860014b89b8e 100644
--- a/drivers/acpi/pci_mcfg.c
+++ b/drivers/acpi/pci_mcfg.c
@@ -41,6 +41,8 @@ struct mcfg_fixup {
 static struct mcfg_fixup mcfg_quirks[] = {
 /*	{ OEM_ID, OEM_TABLE_ID, REV, SEGMENT, BUS_RANGE, ops, cfgres }, */
 
+#ifdef CONFIG_ARM64
+
 #define AL_ECAM(table_id, rev, seg, ops) \
 	{ "AMAZON", table_id, rev, seg, MCFG_BUS_ANY, ops }
 
@@ -169,6 +171,17 @@ static struct mcfg_fixup mcfg_quirks[] = {
 	ALTRA_ECAM_QUIRK(1, 13),
 	ALTRA_ECAM_QUIRK(1, 14),
 	ALTRA_ECAM_QUIRK(1, 15),
+#endif /* ARM64 */
+
+#ifdef CONFIG_LOONGARCH
+#define LOONGSON_ECAM_MCFG(table_id, seg) \
+	{ "LOONGS", table_id, 1, seg, MCFG_BUS_ANY, &loongson_pci_ecam_ops }
+
+	LOONGSON_ECAM_MCFG("\0", 0),
+	LOONGSON_ECAM_MCFG("LOONGSON", 0),
+	LOONGSON_ECAM_MCFG("\0", 1),
+	LOONGSON_ECAM_MCFG("LOONGSON", 1),
+#endif /* LOONGARCH */
 };
 
 static char mcfg_oem_id[ACPI_OEM_ID_SIZE];
diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index 5e1e3796efa4..77aa7272425c 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -287,7 +287,7 @@ config PCI_HYPERV_INTERFACE
 config PCI_LOONGSON
 	bool "LOONGSON PCI Controller"
 	depends on MACH_LOONGSON64 || COMPILE_TEST
-	depends on OF
+	depends on OF || ACPI
 	depends on PCI_QUIRKS
 	default MACH_LOONGSON64
 	help
diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
index b2c81c762599..81361a056377 100644
--- a/drivers/pci/controller/pci-loongson.c
+++ b/drivers/pci/controller/pci-loongson.c
@@ -9,6 +9,8 @@
 #include <linux/of_pci.h>
 #include <linux/pci.h>
 #include <linux/pci_ids.h>
+#include <linux/pci-acpi.h>
+#include <linux/pci-ecam.h>
 
 #include "../pci.h"
 
@@ -92,6 +94,18 @@ static void loongson_mrrs_quirk(struct pci_dev *dev)
 }
 DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, loongson_mrrs_quirk);
 
+static struct loongson_pci *pci_bus_to_loongson_pci(struct pci_bus *bus)
+{
+	struct pci_config_window *cfg;
+
+	if (acpi_disabled)
+		return (struct loongson_pci *)(bus->sysdata);
+	else {
+		cfg = bus->sysdata;
+		return (struct loongson_pci *)(cfg->priv);
+	}
+}
+
 static void __iomem *cfg1_map(struct loongson_pci *priv, int bus,
 				unsigned int devfn, int where)
 {
@@ -119,8 +133,10 @@ static void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devf
 			       int where)
 {
 	unsigned char busnum = bus->number;
-	struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
-	struct loongson_pci *priv =  pci_host_bridge_priv(bridge);
+	struct loongson_pci *priv = pci_bus_to_loongson_pci(bus);
+
+	if (pci_is_root_bus(bus))
+		busnum = 0;
 
 	/*
 	 * Do not read more than one device on the bus other than
@@ -141,6 +157,8 @@ static void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devf
 	return NULL;
 }
 
+#ifdef CONFIG_OF
+
 static int loongson_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
 {
 	int irq;
@@ -242,3 +260,35 @@ static struct platform_driver loongson_pci_driver = {
 	.probe = loongson_pci_probe,
 };
 builtin_platform_driver(loongson_pci_driver);
+
+#endif
+
+#ifdef CONFIG_ACPI
+
+static int loongson_pci_ecam_init(struct pci_config_window *cfg)
+{
+	struct device *dev = cfg->parent;
+	struct loongson_pci *priv;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	cfg->priv = priv;
+	priv->flags = FLAG_CFG1 | FLAG_DEV_FIX,
+	priv->cfg1_base = cfg->win - (cfg->busr.start << 16);
+
+	return 0;
+}
+
+const struct pci_ecam_ops loongson_pci_ecam_ops = {
+	.bus_shift = 16,
+	.init	   = loongson_pci_ecam_init,
+	.pci_ops   = {
+		.map_bus = pci_loongson_map_bus,
+		.read	 = pci_generic_config_read,
+		.write	 = pci_generic_config_write,
+	}
+};
+
+#endif
diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h
index adea5a4771cf..6b1301e2498e 100644
--- a/include/linux/pci-ecam.h
+++ b/include/linux/pci-ecam.h
@@ -87,6 +87,7 @@ extern const struct pci_ecam_ops xgene_v1_pcie_ecam_ops; /* APM X-Gene PCIe v1 *
 extern const struct pci_ecam_ops xgene_v2_pcie_ecam_ops; /* APM X-Gene PCIe v2.x */
 extern const struct pci_ecam_ops al_pcie_ops;	/* Amazon Annapurna Labs PCIe */
 extern const struct pci_ecam_ops tegra194_pcie_ops; /* Tegra194 PCIe */
+extern const struct pci_ecam_ops loongson_pci_ecam_ops; /* Loongson PCIe */
 #endif
 
 #if IS_ENABLED(CONFIG_PCI_HOST_COMMON)
-- 
2.27.0

[PATCH V8 3/5] PCI: Improve the MRRS quirk for LS7A

[Huacai Chen]

In new revision of LS7A, some PCIe ports support larger value than 256,
but their maximum supported MRRS values are not detectable. Moreover,
the current loongson_mrrs_quirk() cannot avoid devices increasing its
MRRS after pci_enable_device(), and some devices (e.g. Realtek 8169)
will actually set a big value in its driver. So the only possible way
is configure MRRS of all devices in BIOS, and add a pci host bridge bit
flag (i.e., no_inc_mrrs) to stop the increasing MRRS operations.

However, according to PCIe Spec, it is legal for an OS to program any
value for MRRS, and it is also legal for an endpoint to generate a Read
Request with any size up to its MRRS. As the hardware engineers say, the
root cause here is LS7A doesn't break up large read requests. In detail,
LS7A PCIe port reports CA (Completer Abort) if it receives a Memory Read
request with a size that's "too big" ("too big" means larger than the
PCIe ports can handle, which means 256 for some ports and 4096 for the
others, and of course this is a problem in the LS7A's hardware design).

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 drivers/pci/controller/pci-loongson.c | 47 ++++++++++-----------------
 drivers/pci/pci.c                     |  6 ++++
 include/linux/pci.h                   |  1 +
 3 files changed, 25 insertions(+), 29 deletions(-)

diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
index 81361a056377..b249f46739ba 100644
--- a/drivers/pci/controller/pci-loongson.c
+++ b/drivers/pci/controller/pci-loongson.c
@@ -62,37 +62,26 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
 			DEV_LS7A_LPC, system_bus_quirk);
 
-static void loongson_mrrs_quirk(struct pci_dev *dev)
+static void loongson_mrrs_quirk(struct pci_dev *pdev)
 {
-	struct pci_bus *bus = dev->bus;
-	struct pci_dev *bridge;
-	static const struct pci_device_id bridge_devids[] = {
-		{ PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_0) },
-		{ PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_1) },
-		{ PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_2) },
-		{ 0, },
-	};
-
-	/* look for the matching bridge */
-	while (!pci_is_root_bus(bus)) {
-		bridge = bus->self;
-		bus = bus->parent;
-		/*
-		 * Some Loongson PCIe ports have a h/w limitation of
-		 * 256 bytes maximum read request size. They can't handle
-		 * anything larger than this. So force this limit on
-		 * any devices attached under these ports.
-		 */
-		if (pci_match_id(bridge_devids, bridge)) {
-			if (pcie_get_readrq(dev) > 256) {
-				pci_info(dev, "limiting MRRS to 256\n");
-				pcie_set_readrq(dev, 256);
-			}
-			break;
-		}
-	}
+	/*
+	 * Some Loongson PCIe ports have h/w limitations of maximum read
+	 * request size. They can't handle anything larger than this. So
+	 * force this limit on any devices attached under these ports.
+	 */
+	struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus);
+
+	if (!bridge)
+		return;
+
+	bridge->no_inc_mrrs = 1;
 }
-DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, loongson_mrrs_quirk);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
+			DEV_PCIE_PORT_0, loongson_mrrs_quirk);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
+			DEV_PCIE_PORT_1, loongson_mrrs_quirk);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
+			DEV_PCIE_PORT_2, loongson_mrrs_quirk);
 
 static struct loongson_pci *pci_bus_to_loongson_pci(struct pci_bus *bus)
 {
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index aacf575c15cf..3279da8ce2dd 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5800,6 +5800,7 @@ int pcie_set_readrq(struct pci_dev *dev, int rq)
 {
 	u16 v;
 	int ret;
+	struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus);
 
 	if (rq < 128 || rq > 4096 || !is_power_of_2(rq))
 		return -EINVAL;
@@ -5818,6 +5819,11 @@ int pcie_set_readrq(struct pci_dev *dev, int rq)
 
 	v = (ffs(rq) - 8) << 12;
 
+	if (bridge->no_inc_mrrs) {
+		if (rq > pcie_get_readrq(dev))
+			return -EINVAL;
+	}
+
 	ret = pcie_capability_clear_and_set_word(dev, PCI_EXP_DEVCTL,
 						  PCI_EXP_DEVCTL_READRQ, v);
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 540b377ca8f6..e2583c2785e2 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -541,6 +541,7 @@ struct pci_host_bridge {
 	void		*release_data;
 	unsigned int	ignore_reset_delay:1;	/* For entire hierarchy */
 	unsigned int	no_ext_tags:1;		/* No Extended Tags */
+	unsigned int	no_inc_mrrs:1;		/* No Increase MRRS */
 	unsigned int	native_aer:1;		/* OS may use PCIe AER */
 	unsigned int	native_pcie_hotplug:1;	/* OS may use PCIe hotplug */
 	unsigned int	native_shpc_hotplug:1;	/* OS may use SHPC hotplug */
-- 
2.27.0

[PATCH V8 4/5] PCI: Add quirk for LS7A to avoid reboot failure

[Huacai Chen]

Commit cc27b735ad3a75574a ("PCI/portdrv: Turn off PCIe services during
shutdown") causes poweroff/reboot failure on systems with LS7A chipset.
We found that if we remove "pci_command &= ~PCI_COMMAND_MASTER;" in
do_pci_disable_device(), it can work well. The hardware engineer says
that the root cause is that CPU is still accessing PCIe devices while
poweroff/reboot, and if we disable the Bus Master Bit at this time, the
PCIe controller doesn't forward requests to downstream devices, and also
doesn't send TIMEOUT to CPU, which causes CPU wait forever (hardware
deadlock). This behavior is a PCIe protocol violation (Bus Master should
not be involved in CPU MMIO transactions), and it will be fixed in new
revisions of hardware (add timeout mechanism for CPU read request,
whether or not Bus Master bit is cleared).

On some x86 platforms, radeon/amdgpu devices can cause similar problems
[1][2]. Once before I wanted to make a single patch to solve "all of
these problems" together, but it seems unreasonable because maybe they
are not exactly the same problem. So, this patch just add a quirk for
LS7A to avoid clearing Bus Master bit in pcie_port_device_remove(), and
leave other platforms as is.

[1] https://bugs.freedesktop.org/show_bug.cgi?id=97980
[2] https://bugs.freedesktop.org/show_bug.cgi?id=98638

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 drivers/pci/controller/pci-loongson.c | 20 ++++++++++++++++++++
 drivers/pci/pcie/portdrv_core.c       |  6 +++++-
 include/linux/pci.h                   |  1 +
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
index b249f46739ba..d91d1c130374 100644
--- a/drivers/pci/controller/pci-loongson.c
+++ b/drivers/pci/controller/pci-loongson.c
@@ -83,6 +83,26 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
 			DEV_PCIE_PORT_2, loongson_mrrs_quirk);
 
+static void loongson_bmaster_quirk(struct pci_dev *pdev)
+{
+	/*
+	 * Some Loongson PCIe ports will cause CPU deadlock if disable
+	 * the Bus Master bit during poweroff/reboot.
+	 */
+	struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus);
+
+	if (!bridge)
+		return;
+
+	bridge->no_dis_bmaster = 1;
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
+			DEV_PCIE_PORT_0, loongson_bmaster_quirk);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
+			DEV_PCIE_PORT_1, loongson_bmaster_quirk);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
+			DEV_PCIE_PORT_2, loongson_bmaster_quirk);
+
 static struct loongson_pci *pci_bus_to_loongson_pci(struct pci_bus *bus)
 {
 	struct pci_config_window *cfg;
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index e1fed6649c41..7f9549a1f48b 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -486,9 +486,13 @@ EXPORT_SYMBOL_GPL(pcie_port_find_device);
  */
 void pcie_port_device_remove(struct pci_dev *dev)
 {
+	struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus);
+
 	device_for_each_child(&dev->dev, NULL, remove_iter);
 	pci_free_irq_vectors(dev);
-	pci_disable_device(dev);
+
+	if (!bridge->no_dis_bmaster)
+		pci_disable_device(dev);
 }
 
 /**
diff --git a/include/linux/pci.h b/include/linux/pci.h
index e2583c2785e2..46dfbb61f2f0 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -542,6 +542,7 @@ struct pci_host_bridge {
 	unsigned int	ignore_reset_delay:1;	/* For entire hierarchy */
 	unsigned int	no_ext_tags:1;		/* No Extended Tags */
 	unsigned int	no_inc_mrrs:1;		/* No Increase MRRS */
+	unsigned int	no_dis_bmaster:1;	/* No Disable Bus Master */
 	unsigned int	native_aer:1;		/* OS may use PCIe AER */
 	unsigned int	native_pcie_hotplug:1;	/* OS may use PCIe hotplug */
 	unsigned int	native_shpc_hotplug:1;	/* OS may use SHPC hotplug */
-- 
2.27.0

[PATCH V8 5/5] PCI: Add quirk for multifunction devices of LS7A

[Huacai Chen]

From: Jianmin Lv <lvjianmin@loongson.cn>

In LS7A, multifunction device use same PCI PIN (because the PIN register
report the same INTx value to each function) but we need different IRQ
for different functions, so add a quirk to fix it for standard PCI PIN
usage.

This patch only affect ACPI based systems (and only needed by ACPI based
systems, too). For DT based systems, the irq mappings is defined in .dts
files and be handled by of_irq_parse_pci().

Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 drivers/pci/controller/pci-loongson.c | 29 +++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
index d91d1c130374..8b12e7da1238 100644
--- a/drivers/pci/controller/pci-loongson.c
+++ b/drivers/pci/controller/pci-loongson.c
@@ -22,6 +22,12 @@
 #define DEV_LS2K_APB	0x7a02
 #define DEV_LS7A_CONF	0x7a10
 #define DEV_LS7A_LPC	0x7a0c
+#define DEV_LS7A_GMAC	0x7a03
+#define DEV_LS7A_DC	0x7a06
+#define DEV_LS7A_GPU	0x7a15
+#define DEV_LS7A_AHCI	0x7a08
+#define DEV_LS7A_EHCI	0x7a14
+#define DEV_LS7A_OHCI	0x7a24
 
 #define FLAG_CFG0	BIT(0)
 #define FLAG_CFG1	BIT(1)
@@ -103,6 +109,29 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
 			DEV_PCIE_PORT_2, loongson_bmaster_quirk);
 
+static void loongson_pci_pin_quirk(struct pci_dev *pdev)
+{
+	pdev->pin = 1 + (PCI_FUNC(pdev->devfn) & 3);
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
+			DEV_LS7A_DC, loongson_pci_pin_quirk);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
+			DEV_LS7A_GPU, loongson_pci_pin_quirk);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
+			DEV_LS7A_GMAC, loongson_pci_pin_quirk);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
+			DEV_LS7A_AHCI, loongson_pci_pin_quirk);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
+			DEV_LS7A_EHCI, loongson_pci_pin_quirk);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
+			DEV_LS7A_OHCI, loongson_pci_pin_quirk);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
+			DEV_PCIE_PORT_0, loongson_pci_pin_quirk);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
+			DEV_PCIE_PORT_1, loongson_pci_pin_quirk);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
+			DEV_PCIE_PORT_2, loongson_pci_pin_quirk);
+
 static struct loongson_pci *pci_bus_to_loongson_pci(struct pci_bus *bus)
 {
 	struct pci_config_window *cfg;
-- 
2.27.0