diff mbox

[RESEND] PCI: mvebu - Support a bridge with no IO port window

Message ID 1380650281-16175-2-git-send-email-jgunthorpe@obsidianresearch.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jason Gunthorpe Oct. 1, 2013, 5:58 p.m. UTC
Make pcie-io-aperture and the IO port MBUS ID in ranges optional.
If not provided the bridge reports to Linux that IO space mapping is
not supported and refuses to configure an IO mbus window.

This allows both complete disable (do not specify pcie-io-aperture) and
per-port disable (do not specify a IO target ranges entry for the port)

Most PCIE devices these days do not require IO support to function,
so having an option to disable it in the driver is useful.

This depends on 'bus: mvebu-mbus: Fix optional pcie-mem/io-aperture properties'
to work properly.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
---
 drivers/pci/host/pci-mvebu.c | 62 ++++++++++++++++++++++++++++++--------------
 1 file changed, 42 insertions(+), 20 deletions(-)

Comments

Thomas Petazzoni Oct. 3, 2013, 12:06 p.m. UTC | #1
Dear Jason Gunthorpe,

On Tue,  1 Oct 2013 11:58:01 -0600, Jason Gunthorpe wrote:
> Make pcie-io-aperture and the IO port MBUS ID in ranges optional.
> If not provided the bridge reports to Linux that IO space mapping is
> not supported and refuses to configure an IO mbus window.
> 
> This allows both complete disable (do not specify pcie-io-aperture) and
> per-port disable (do not specify a IO target ranges entry for the port)
> 
> Most PCIE devices these days do not require IO support to function,
> so having an option to disable it in the driver is useful.
> 
> This depends on 'bus: mvebu-mbus: Fix optional pcie-mem/io-aperture properties'
> to work properly.
> 
> Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>

This doesn't work here, I get multiple warnings "Attempt to set IO when
IO is disabled" :

------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at /home/thomas/projets/linux-2.6/drivers/pci/host/pci-mvebu.c:302 mvebu_pcie_wr_conf+0x2c0/0x44c()
Device: mvebu-pcie
Attempt to set IO when IO is disabled
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.12.0-rc1-00003-ga85b362 #6
[<c0015798>] (unwind_backtrace+0x0/0xf8) from [<c0011770>] (show_stack+0x10/0x14)
[<c0011770>] (show_stack+0x10/0x14) from [<c0372c08>] (dump_stack+0x70/0x8c)
[<c0372c08>] (dump_stack+0x70/0x8c) from [<c001d5bc>] (warn_slowpath_common+0x64/0x88)
[<c001d5bc>] (warn_slowpath_common+0x64/0x88) from [<c001d674>] (warn_slowpath_fmt+0x30/0x40)
[<c001d674>] (warn_slowpath_fmt+0x30/0x40) from [<c0187080>] (mvebu_pcie_wr_conf+0x2c0/0x44c)
[<c0187080>] (mvebu_pcie_wr_conf+0x2c0/0x44c) from [<c01770fc>] (pci_bus_write_config_word+0x60/0x78)
[<c01770fc>] (pci_bus_write_config_word+0x60/0x78) from [<c03708b4>] (__pci_bus_size_bridges+0x708/0x7c0)
[<c03708b4>] (__pci_bus_size_bridges+0x708/0x7c0) from [<c03701e0>] (__pci_bus_size_bridges+0x34/0x7c0)
[<c03701e0>] (__pci_bus_size_bridges+0x34/0x7c0) from [<c00134c4>] (pci_common_init_dev+0x1b0/0x2dc)
[<c00134c4>] (pci_common_init_dev+0x1b0/0x2dc) from [<c04a3f68>] (mvebu_pcie_probe+0x444/0x48c)
[<c04a3f68>] (mvebu_pcie_probe+0x444/0x48c) from [<c01b69dc>] (platform_drv_probe+0x18/0x1c)
[<c01b69dc>] (platform_drv_probe+0x18/0x1c) from [<c01b5858>] (driver_probe_device+0xf4/0x210)
[<c01b5858>] (driver_probe_device+0xf4/0x210) from [<c01b5a00>] (__driver_attach+0x8c/0x90)
[<c01b5a00>] (__driver_attach+0x8c/0x90) from [<c01b3eb8>] (bus_for_each_dev+0x54/0x88)
[<c01b3eb8>] (bus_for_each_dev+0x54/0x88) from [<c01b4f60>] (bus_add_driver+0xd4/0x258)
[<c01b4f60>] (bus_add_driver+0xd4/0x258) from [<c01b6038>] (driver_register+0x78/0xf4)
[<c01b6038>] (driver_register+0x78/0xf4) from [<c01b6bc0>] (platform_driver_probe+0x1c/0xa0)
[<c01b6bc0>] (platform_driver_probe+0x1c/0xa0) from [<c0008878>] (do_one_initcall+0xe4/0x140)
[<c0008878>] (do_one_initcall+0xe4/0x140) from [<c0492b60>] (kernel_init_freeable+0xfc/0x1c4)
[<c0492b60>] (kernel_init_freeable+0xfc/0x1c4) from [<c036f0cc>] (kernel_init+0x8/0xe4)
[<c036f0cc>] (kernel_init+0x8/0xe4) from [<c000e3d8>] (ret_from_fork+0x14/0x3c)
---[ end trace 70bc10e370e10347 ]---

> +static inline bool mvebu_has_ioport(struct mvebu_pcie_port *port)
> +{
> +	return port->io_target == -1 && port->io_attr == -1;

Are you sure the logic is not reverted here? I.e, this shouldn't be !=
-1 in both cases?

> +}
> +
>  static bool mvebu_pcie_link_up(struct mvebu_pcie_port *port)
>  {
>  	return !(readl(port->base + PCIE_STAT_OFF) & PCIE_STAT_LINK_DOWN);
> @@ -292,6 +297,12 @@ static void mvebu_pcie_handle_iobase_change(struct mvebu_pcie_port *port)
>  		return;
>  	}
>  
> +	if (!mvebu_has_ioport(port)) {
> +		dev_WARN(&port->pcie->pdev->dev,
> +			 "Attempt to set IO when IO is disabled\n");
> +		return;
> +	}
> +
>  	/*
>  	 * We read the PCI-to-PCI bridge emulated registers, and
>  	 * calculate the base address and size of the address decoding
> @@ -405,9 +416,12 @@ static int mvebu_sw_pci_bridge_read(struct mvebu_pcie_port *port,
>  		break;
>  
>  	case PCI_IO_BASE:
> -		*value = (bridge->secondary_status << 16 |
> -			  bridge->iolimit          <<  8 |
> -			  bridge->iobase);
> +		if (!mvebu_has_ioport(port))
> +			*value = 0;
> +		else
> +			*value = (bridge->secondary_status << 16 |
> +				  bridge->iolimit          <<  8 |
> +				  bridge->iobase);

While I do understand that you're returning 0 for iolimit and iobase,
I'm not sure why the secondary status is affected by the value of
mvebu_has_ioport().

>  static int mvebu_get_tgt_attr(struct device_node *np, int devfn,
> -			      unsigned long type, int *tgt, int *attr)
> +			      unsigned long type,
> +			      unsigned int *tgt,
> +			      unsigned int *attr)
>  {
>  	const int na = 3, ns = 2;
>  	const __be32 *range;
>  	int rlen, nranges, rangesz, pna, i;
>  
> +	*tgt = -1;
> +	*attr = -1;
> +
>  	range = of_get_property(np, "ranges", &rlen);
>  	if (!range)
>  		return -EINVAL;
> @@ -798,16 +821,15 @@ static int __init mvebu_pcie_probe(struct platform_device *pdev)
>  	}
>  
>  	mvebu_mbus_get_pcie_io_aperture(&pcie->io);
> -	if (resource_size(&pcie->io) == 0) {
> -		dev_err(&pdev->dev, "invalid I/O aperture size\n");
> -		return -EINVAL;
> -	}
>  
> -	pcie->realio.flags = pcie->io.flags;
> -	pcie->realio.start = PCIBIOS_MIN_IO;
> -	pcie->realio.end = min_t(resource_size_t,
> -				  IO_SPACE_LIMIT,
> -				  resource_size(&pcie->io));
> +	if (resource_size(&pcie->io) != 0) {
> +		pcie->realio.flags = pcie->io.flags;
> +		pcie->realio.start = PCIBIOS_MIN_IO;
> +		pcie->realio.end = min_t(resource_size_t,
> +					 IO_SPACE_LIMIT,
> +					 resource_size(&pcie->io));
> +	} else
> +		pcie->realio = pcie->io;
>  
>  	/* Get the bus range */
>  	ret = of_pci_parse_bus_range(np, &pcie->busn);
> @@ -864,12 +886,12 @@ static int __init mvebu_pcie_probe(struct platform_device *pdev)
>  			continue;
>  		}
>  
> -		ret = mvebu_get_tgt_attr(np, port->devfn, IORESOURCE_IO,
> -					 &port->io_target, &port->io_attr);
> -		if (ret < 0) {
> -			dev_err(&pdev->dev, "PCIe%d.%d: cannot get tgt/attr for io window\n",
> -				port->port, port->lane);
> -			continue;
> +		if (resource_size(&pcie->io) != 0)
> +			mvebu_get_tgt_attr(np, port->devfn, IORESOURCE_IO,
> +					   &port->io_target, &port->io_attr);
> +		else {
> +			port->io_target = -1;
> +			port->io_attr = -1;
>  		}
>  
>  		port->base = mvebu_pcie_map_registers(pdev, child, port);

Thanks!

Thomas
Jason Gunthorpe Oct. 15, 2013, 7:51 p.m. UTC | #2
On Thu, Oct 03, 2013 at 02:06:48PM +0200, Thomas Petazzoni wrote:
> Dear Jason Gunthorpe,
> 
> On Tue,  1 Oct 2013 11:58:01 -0600, Jason Gunthorpe wrote:
> > Make pcie-io-aperture and the IO port MBUS ID in ranges optional.
> > If not provided the bridge reports to Linux that IO space mapping is
> > not supported and refuses to configure an IO mbus window.
> > 
> > This allows both complete disable (do not specify pcie-io-aperture) and
> > per-port disable (do not specify a IO target ranges entry for the port)
> > 
> > Most PCIE devices these days do not require IO support to function,
> > so having an option to disable it in the driver is useful.
> > 
> > This depends on 'bus: mvebu-mbus: Fix optional pcie-mem/io-aperture properties'
> > to work properly.
> 
> This doesn't work here, I get multiple warnings "Attempt to set IO when
> IO is disabled" :

Okay, I looked into this.

The warnings are caused by the bogus mvebu_has_ioport you noted, 
and this is also required:

        /* Are the new iobase/iolimit values invalid? */
-       if (port->bridge.iolimit < port->bridge.iobase ||
+       if (port->bridge.iolimit <= port->bridge.iobase ||
            port->bridge.iolimitupper < port->bridge.iobaseupper) {

> >  	case PCI_IO_BASE:
> > -		*value = (bridge->secondary_status << 16 |
> > -			  bridge->iolimit          <<  8 |
> > -			  bridge->iobase);
> > +		if (!mvebu_has_ioport(port))
> > +			*value = 0;
> > +		else
> > +			*value = (bridge->secondary_status << 16 |
> > +				  bridge->iolimit          <<  8 |
> > +				  bridge->iobase);
> 
> While I do understand that you're returning 0 for iolimit and iobase,
> I'm not sure why the secondary status is affected by the value of
> mvebu_has_ioport().

This is an error, of sorts. 0 is actually the correct value for 
secondary status with the current capabilities of the driver.. I'll
fix it here as you noted and send a patch to fix that up separately.

New patches in a sec..

Thanks,
Jason
diff mbox

Patch

diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
index f2d61f5..5ddba68 100644
--- a/drivers/pci/host/pci-mvebu.c
+++ b/drivers/pci/host/pci-mvebu.c
@@ -132,6 +132,11 @@  struct mvebu_pcie_port {
 	size_t iowin_size;
 };
 
+static inline bool mvebu_has_ioport(struct mvebu_pcie_port *port)
+{
+	return port->io_target == -1 && port->io_attr == -1;
+}
+
 static bool mvebu_pcie_link_up(struct mvebu_pcie_port *port)
 {
 	return !(readl(port->base + PCIE_STAT_OFF) & PCIE_STAT_LINK_DOWN);
@@ -292,6 +297,12 @@  static void mvebu_pcie_handle_iobase_change(struct mvebu_pcie_port *port)
 		return;
 	}
 
+	if (!mvebu_has_ioport(port)) {
+		dev_WARN(&port->pcie->pdev->dev,
+			 "Attempt to set IO when IO is disabled\n");
+		return;
+	}
+
 	/*
 	 * We read the PCI-to-PCI bridge emulated registers, and
 	 * calculate the base address and size of the address decoding
@@ -405,9 +416,12 @@  static int mvebu_sw_pci_bridge_read(struct mvebu_pcie_port *port,
 		break;
 
 	case PCI_IO_BASE:
-		*value = (bridge->secondary_status << 16 |
-			  bridge->iolimit          <<  8 |
-			  bridge->iobase);
+		if (!mvebu_has_ioport(port))
+			*value = 0;
+		else
+			*value = (bridge->secondary_status << 16 |
+				  bridge->iolimit          <<  8 |
+				  bridge->iobase);
 		break;
 
 	case PCI_MEMORY_BASE:
@@ -465,6 +479,8 @@  static int mvebu_sw_pci_bridge_write(struct mvebu_pcie_port *port,
 	switch (where & ~3) {
 	case PCI_COMMAND:
 		bridge->command = value & 0xffff;
+		if (!mvebu_has_ioport(port))
+			bridge->command &= ~PCI_COMMAND_IO;
 		break;
 
 	case PCI_BASE_ADDRESS_0 ... PCI_BASE_ADDRESS_1:
@@ -630,7 +646,9 @@  static int __init mvebu_pcie_setup(int nr, struct pci_sys_data *sys)
 	struct mvebu_pcie *pcie = sys_to_pcie(sys);
 	int i;
 
-	pci_add_resource_offset(&sys->resources, &pcie->realio, sys->io_offset);
+	if (resource_size(&pcie->realio) != 0)
+		pci_add_resource_offset(&sys->resources, &pcie->realio,
+					sys->io_offset);
 	pci_add_resource_offset(&sys->resources, &pcie->mem, sys->mem_offset);
 	pci_add_resource(&sys->resources, &pcie->busn);
 
@@ -739,12 +757,17 @@  mvebu_pcie_map_registers(struct platform_device *pdev,
 #define DT_CPUADDR_TO_ATTR(cpuaddr)   (((cpuaddr) >> 48) & 0xFF)
 
 static int mvebu_get_tgt_attr(struct device_node *np, int devfn,
-			      unsigned long type, int *tgt, int *attr)
+			      unsigned long type,
+			      unsigned int *tgt,
+			      unsigned int *attr)
 {
 	const int na = 3, ns = 2;
 	const __be32 *range;
 	int rlen, nranges, rangesz, pna, i;
 
+	*tgt = -1;
+	*attr = -1;
+
 	range = of_get_property(np, "ranges", &rlen);
 	if (!range)
 		return -EINVAL;
@@ -798,16 +821,15 @@  static int __init mvebu_pcie_probe(struct platform_device *pdev)
 	}
 
 	mvebu_mbus_get_pcie_io_aperture(&pcie->io);
-	if (resource_size(&pcie->io) == 0) {
-		dev_err(&pdev->dev, "invalid I/O aperture size\n");
-		return -EINVAL;
-	}
 
-	pcie->realio.flags = pcie->io.flags;
-	pcie->realio.start = PCIBIOS_MIN_IO;
-	pcie->realio.end = min_t(resource_size_t,
-				  IO_SPACE_LIMIT,
-				  resource_size(&pcie->io));
+	if (resource_size(&pcie->io) != 0) {
+		pcie->realio.flags = pcie->io.flags;
+		pcie->realio.start = PCIBIOS_MIN_IO;
+		pcie->realio.end = min_t(resource_size_t,
+					 IO_SPACE_LIMIT,
+					 resource_size(&pcie->io));
+	} else
+		pcie->realio = pcie->io;
 
 	/* Get the bus range */
 	ret = of_pci_parse_bus_range(np, &pcie->busn);
@@ -864,12 +886,12 @@  static int __init mvebu_pcie_probe(struct platform_device *pdev)
 			continue;
 		}
 
-		ret = mvebu_get_tgt_attr(np, port->devfn, IORESOURCE_IO,
-					 &port->io_target, &port->io_attr);
-		if (ret < 0) {
-			dev_err(&pdev->dev, "PCIe%d.%d: cannot get tgt/attr for io window\n",
-				port->port, port->lane);
-			continue;
+		if (resource_size(&pcie->io) != 0)
+			mvebu_get_tgt_attr(np, port->devfn, IORESOURCE_IO,
+					   &port->io_target, &port->io_attr);
+		else {
+			port->io_target = -1;
+			port->io_attr = -1;
 		}
 
 		port->base = mvebu_pcie_map_registers(pdev, child, port);