linux-kernel - Re: [PATCH v8 5/8] PCI: cadence: Simplify code to get register base address for configuring BAR

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Message-ID: <20210817152412.GA3016169@bjorn-Precision-5520>
Date:   Tue, 17 Aug 2021 10:24:12 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Kishon Vijay Abraham I <kishon@...com>
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Rob Herring <robh+dt@...nel.org>,
        Tom Joseph <tjoseph@...ence.com>,
        Jingoo Han <jingoohan1@...il.com>,
        Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        Marek Vasut <marek.vasut+renesas@...il.com>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Jonathan Corbet <corbet@....net>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-pci@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org,
        linux-rockchip@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org,
        Lokesh Vutla <lokeshvutla@...com>
Subject: Re: [PATCH v8 5/8] PCI: cadence: Simplify code to get register base
 address for configuring BAR

On Wed, Aug 11, 2021 at 12:16:53PM +0530, Kishon Vijay Abraham I wrote:
> No functional change. Simplify code to get register base address for
> configuring PCI BAR.
> 
> Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
> ---
>  .../pci/controller/cadence/pcie-cadence-ep.c   | 18 ++++--------------
>  drivers/pci/controller/cadence/pcie-cadence.h  |  2 ++
>  2 files changed, 6 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/drivers/pci/controller/cadence/pcie-cadence-ep.c
> index 912a15be8bfd..f337f0842400 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence-ep.c
> +++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c
> @@ -97,13 +97,8 @@ static int cdns_pcie_ep_set_bar(struct pci_epc *epc, u8 fn, u8 vfn,
>  	cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR1(fn, bar),
>  			 addr1);
>  
> -	if (bar < BAR_4) {
> -		reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG0(fn);
> -		b = bar;
> -	} else {
> -		reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG1(fn);
> -		b = bar - BAR_4;
> -	}
> +	reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG(bar, fn);
> +	b = (bar < BAR_4) ? bar : bar - BAR_4;
>  
>  	cfg = cdns_pcie_readl(pcie, reg);
>  	cfg &= ~(CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b) |
> @@ -126,13 +121,8 @@ static void cdns_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn, u8 vfn,
>  	enum pci_barno bar = epf_bar->barno;
>  	u32 reg, cfg, b, ctrl;
>  
> -	if (bar < BAR_4) {
> -		reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG0(fn);
> -		b = bar;
> -	} else {
> -		reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG1(fn);
> -		b = bar - BAR_4;
> -	}
> +	reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG(bar, fn);
> +	b = (bar < BAR_4) ? bar : bar - BAR_4;
>  
>  	ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED;
>  	cfg = cdns_pcie_readl(pcie, reg);
> diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h
> index 30db2d68c17a..d5b1fcf2c39d 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence.h
> +++ b/drivers/pci/controller/cadence/pcie-cadence.h
> @@ -46,6 +46,8 @@
>  #define  CDNS_PCIE_LM_EP_ID_BUS_SHIFT	8
>  
>  /* Endpoint Function f BAR b Configuration Registers */
> +#define CDNS_PCIE_LM_EP_FUNC_BAR_CFG(bar, fn) \
> +	(((bar) < 4) ? CDNS_PCIE_LM_EP_FUNC_BAR_CFG0(fn) : CDNS_PCIE_LM_EP_FUNC_BAR_CFG1(fn))

Why do we use "BAR_4" above and "4" here?  Shouldn't they look the
same?

>  #define CDNS_PCIE_LM_EP_FUNC_BAR_CFG0(fn) \
>  	(CDNS_PCIE_LM_BASE + 0x0240 + (fn) * 0x0008)
>  #define CDNS_PCIE_LM_EP_FUNC_BAR_CFG1(fn) \
> -- 
> 2.17.1
>