[v2] PCI: brcmstb: Misc small tweaks and fixes

[PATCH v2 2/8] PCI: brcmstb: Write to internal register to change link cap

Posted by Jim Quinlan 10 months, 1 week ago

The driver was mistakenly writing to a RO config-space register
(PCI_EXP_LNKCAP).  Although harmless in this case, the proper destination
is an internal RW register that is reflected by PCI_EXP_LNKCAP.

Fixes: c0452137034bda8f686dd9a2e167949bfffd6776 ("PCI: brcmstb: Add Broadcom STB PCIe host controller driver")

Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 64a7511e66a8..98542e74aa16 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -413,10 +413,10 @@ static int brcm_pcie_set_ssc(struct brcm_pcie *pcie)
 static void brcm_pcie_set_gen(struct brcm_pcie *pcie, int gen)
 {
 	u16 lnkctl2 = readw(pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCTL2);
-	u32 lnkcap = readl(pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCAP);
+	u32 lnkcap = readl(pcie->base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
 
 	lnkcap = (lnkcap & ~PCI_EXP_LNKCAP_SLS) | gen;
-	writel(lnkcap, pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCAP);
+	writel(lnkcap, pcie->base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
 
 	lnkctl2 = (lnkctl2 & ~0xf) | gen;
 	writew(lnkctl2, pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCTL2);
-- 
2.43.0

Re: [PATCH v2 2/8] PCI: brcmstb: Write to internal register to change link cap

Posted by Manivannan Sadhasivam 9 months, 2 weeks ago

On Fri, Feb 14, 2025 at 12:39:30PM -0500, Jim Quinlan wrote:
> The driver was mistakenly writing to a RO config-space register
> (PCI_EXP_LNKCAP).  Although harmless in this case, the proper destination
> is an internal RW register that is reflected by PCI_EXP_LNKCAP.
> 

You mean to say that writing to RO register doesn't cause any issue, but what
about the link capability not getting updated? It is a bug nevertheless.

> Fixes: c0452137034bda8f686dd9a2e167949bfffd6776 ("PCI: brcmstb: Add Broadcom STB PCIe host controller driver")
> 

Same comment as previous patch.

> Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

- Mani

> ---
>  drivers/pci/controller/pcie-brcmstb.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index 64a7511e66a8..98542e74aa16 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -413,10 +413,10 @@ static int brcm_pcie_set_ssc(struct brcm_pcie *pcie)
>  static void brcm_pcie_set_gen(struct brcm_pcie *pcie, int gen)
>  {
>  	u16 lnkctl2 = readw(pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCTL2);
> -	u32 lnkcap = readl(pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCAP);
> +	u32 lnkcap = readl(pcie->base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
>  
>  	lnkcap = (lnkcap & ~PCI_EXP_LNKCAP_SLS) | gen;
> -	writel(lnkcap, pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCAP);
> +	writel(lnkcap, pcie->base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
>  
>  	lnkctl2 = (lnkctl2 & ~0xf) | gen;
>  	writew(lnkctl2, pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCTL2);
> -- 
> 2.43.0
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 2/8] PCI: brcmstb: Write to internal register to change link cap

Posted by Florian Fainelli 10 months ago


On 2/14/2025 9:39 AM, Jim Quinlan wrote:
> The driver was mistakenly writing to a RO config-space register
> (PCI_EXP_LNKCAP).  Although harmless in this case, the proper destination
> is an internal RW register that is reflected by PCI_EXP_LNKCAP.
> 
> Fixes: c0452137034bda8f686dd9a2e167949bfffd6776 ("PCI: brcmstb: Add Broadcom STB PCIe host controller driver")

Likewise this needs to be shortened to 12 digits, with that fixed:

Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
-- 
Florian