diff mbox series

[2/8] pci: pci_mvebu: Fix read_config() with PCI_SIZE_8 or PCI_SIZE_16

Message ID 20211022142215.26484-3-pali@kernel.org
State Accepted
Commit 657177ad8e240ea520eba26da5c0ba47bd935787
Delegated to: Stefan Roese
Headers show
Series pci: pci_mvebu: Fix access to config space and PCIe Root Port | expand

Commit Message

Pali Rohár Oct. 22, 2021, 2:22 p.m. UTC 
When reading 8 or 16 bits from config space, use appropriate readb() or
readw() calls. This ensures that PCIe controller does not read more bits
from endpoint card as asked by read_config() function.

Technically there should not be an issue with reading data from config
space which are not later used as there are no clear-by-read registers.
But it is better to use correct read operation based on requested size.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
---
 drivers/pci/pci_mvebu.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

Comments

Stefan Roese Nov. 2, 2021, 10:45 a.m. UTC | #1 
On 22.10.21 16:22, Pali Rohár wrote:
> When reading 8 or 16 bits from config space, use appropriate readb() or
> readw() calls. This ensures that PCIe controller does not read more bits
> from endpoint card as asked by read_config() function.
> 
> Technically there should not be an issue with reading data from config
> space which are not later used as there are no clear-by-read registers.
> But it is better to use correct read operation based on requested size.
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>
> Reviewed-by: Marek Behún <marek.behun@nic.cz>

Reviewed-by: Stefan Roese <sr@denx.de>

Thanks,
Stefan

> ---
>   drivers/pci/pci_mvebu.c | 17 +++++++++++++++--
>   1 file changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/pci_mvebu.c b/drivers/pci/pci_mvebu.c
> index 8175511514ab..3991086e0d29 100644
> --- a/drivers/pci/pci_mvebu.c
> +++ b/drivers/pci/pci_mvebu.c
> @@ -184,9 +184,22 @@ static int mvebu_pcie_read_config(const struct udevice *bus, pci_dev_t bdf,
>   	writel(PCIE_CONF_ADDR(bdf, offset), pcie->base + PCIE_CONF_ADDR_OFF);
>   
>   	/* read data */
> -	data = readl(pcie->base + PCIE_CONF_DATA_OFF);
> +	switch (size) {
> +	case PCI_SIZE_8:
> +		data = readb(pcie->base + PCIE_CONF_DATA_OFF + (offset & 3));
> +		break;
> +	case PCI_SIZE_16:
> +		data = readw(pcie->base + PCIE_CONF_DATA_OFF + (offset & 2));
> +		break;
> +	case PCI_SIZE_32:
> +		data = readl(pcie->base + PCIE_CONF_DATA_OFF);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
>   	debug("(addr,size,val)=(0x%04x, %d, 0x%08x)\n", offset, size, data);
> -	*valuep = pci_conv_32_to_size(data, offset, size);
> +	*valuep = data;
>   
>   	return 0;
>   }
> 


Viele Grüße,
Stefan
diff mbox series

Patch

diff --git a/drivers/pci/pci_mvebu.c b/drivers/pci/pci_mvebu.c
index 8175511514ab..3991086e0d29 100644
--- a/drivers/pci/pci_mvebu.c
+++ b/drivers/pci/pci_mvebu.c
@@ -184,9 +184,22 @@  static int mvebu_pcie_read_config(const struct udevice *bus, pci_dev_t bdf,
 	writel(PCIE_CONF_ADDR(bdf, offset), pcie->base + PCIE_CONF_ADDR_OFF);
 
 	/* read data */
-	data = readl(pcie->base + PCIE_CONF_DATA_OFF);
+	switch (size) {
+	case PCI_SIZE_8:
+		data = readb(pcie->base + PCIE_CONF_DATA_OFF + (offset & 3));
+		break;
+	case PCI_SIZE_16:
+		data = readw(pcie->base + PCIE_CONF_DATA_OFF + (offset & 2));
+		break;
+	case PCI_SIZE_32:
+		data = readl(pcie->base + PCIE_CONF_DATA_OFF);
+		break;
+	default:
+		return -EINVAL;
+	}
+
 	debug("(addr,size,val)=(0x%04x, %d, 0x%08x)\n", offset, size, data);
-	*valuep = pci_conv_32_to_size(data, offset, size);
+	*valuep = data;
 
 	return 0;
 }