[PATCH AUTOSEL 3.18 35/98] mcb: mcb-pci: Only remap the 1st 0x200 bytes of BAR 0

Sasha Levin
2018-10-25T14:17:50Z

From: Johannes Thumshirn <johannes.thumshirn@men.de>

[ Upstream commit 7b7c54914f73966976893747ee8e2ca58166a627 ]

Currently it is not possible to have a kernel with built-in MCB attached
devices. This results out of the fact that mcb-pci requests PCI BAR 0, then
parses the chameleon table and calls the driver's probe function before
releasing BAR 0 again. When building the kernel with modules this is not a
problem (and therefore it wasn't detected by my tests yet).

A solution is to only remap the 1st 0x200 bytes of a Chameleon PCI device.
0x200 bytes is the maximum size of a Chameleon v2 Table.

Also this patch stops disabling the PCI device on successful registration of MCB
devices.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@men.de>
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/mcb/mcb-internal.h | 1 +
drivers/mcb/mcb-pci.c | 27 ++++++++++++++++++---------
2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/drivers/mcb/mcb-internal.h b/drivers/mcb/mcb-internal.h
index f956ef26c0ce..fb7493dcfb79 100644
--- a/drivers/mcb/mcb-internal.h
+++ b/drivers/mcb/mcb-internal.h
@@ -7,6 +7,7 @@
#define PCI_DEVICE_ID_MEN_CHAMELEON 0x4d45
#define CHAMELEON_FILENAME_LEN 12
#define CHAMELEONV2_MAGIC 0xabce
+#define CHAM_HEADER_SIZE 0x200

enum chameleon_descriptor_type {
CHAMELEON_DTYPE_GENERAL = 0x0,
diff --git a/drivers/mcb/mcb-pci.c b/drivers/mcb/mcb-pci.c
index b59181965643..5e1bd5db02c8 100644
--- a/drivers/mcb/mcb-pci.c
+++ b/drivers/mcb/mcb-pci.c
@@ -17,6 +17,7 @@

struct priv {
struct mcb_bus *bus;
+ phys_addr_t mapbase;
void __iomem *base;
};

@@ -31,8 +32,8 @@ static int mcb_pci_get_irq(struct mcb_device *mdev)

static int mcb_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
+ struct resource *res;
struct priv *priv;
- phys_addr_t mapbase;
int ret;
int num_cells;
unsigned long flags;
@@ -47,19 +48,21 @@ static int mcb_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
return -ENODEV;
}

- mapbase = pci_resource_start(pdev, 0);
- if (!mapbase) {
+ priv->mapbase = pci_resource_start(pdev, 0);
+ if (!priv->mapbase) {
dev_err(&pdev->dev, "No PCI resource\n");
goto err_start;
}

- ret = pci_request_region(pdev, 0, KBUILD_MODNAME);
- if (ret) {
- dev_err(&pdev->dev, "Failed to request PCI BARs\n");
+ res = request_mem_region(priv->mapbase, CHAM_HEADER_SIZE,
+ KBUILD_MODNAME);
+ if (IS_ERR(res)) {
+ dev_err(&pdev->dev, "Failed to request PCI memory\n");
+ ret = PTR_ERR(res);
goto err_start;
}

- priv->base = pci_iomap(pdev, 0, 0);
+ priv->base = ioremap(priv->mapbase, CHAM_HEADER_SIZE);
if (!priv->base) {
dev_err(&pdev->dev, "Cannot ioremap\n");
ret = -ENOMEM;
@@ -84,7 +87,7 @@ static int mcb_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)

priv->bus->get_irq = mcb_pci_get_irq;

- ret = chameleon_parse_cells(priv->bus, mapbase, priv->base);
+ ret = chameleon_parse_cells(priv->bus, priv->mapbase, priv->base);
if (ret < 0)
goto err_drvdata;
num_cells = ret;
@@ -93,8 +96,10 @@ static int mcb_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)

mcb_bus_add_devices(priv->bus);

+ return 0;
+
err_drvdata:
- pci_iounmap(pdev, priv->base);
+ iounmap(priv->base);
err_ioremap:
pci_release_region(pdev, 0);
err_start:
@@ -107,6 +112,10 @@ static void mcb_pci_remove(struct pci_dev *pdev)
struct priv *priv = pci_get_drvdata(pdev);

mcb_release_bus(priv->bus);
+
+ iounmap(priv->base);
+ release_region(priv->mapbase, CHAM_HEADER_SIZE);
+ pci_disable_device(pdev);
}

static const struct pci_device_id mcb_pci_tbl[] = {
--
2.17.1