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Tue, 22 Nov 2022 05:55:57 -0800 (PST) Received: from thinkpad ([59.92.98.84]) by smtp.gmail.com with ESMTPSA id r12-20020a63e50c000000b00476dc914262sm9271620pgh.1.2022.11.22.05.55.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Nov 2022 05:55:56 -0800 (PST) Date: Tue, 22 Nov 2022 19:25:50 +0530 From: Manivannan Sadhasivam To: Yoshihiro Shimoda Cc: lpieralisi@kernel.org, robh+dt@kernel.org, kw@linux.com, bhelgaas@google.com, krzk+dt@kernel.org, marek.vasut+renesas@gmail.com, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, fancer.lancer@gmail.com, Sergey.Semin@baikalelectronics.ru Subject: Re: [PATCH v7 5/9] PCI: dwc: Avoid reading a register to detect whether eDMA exists Message-ID: <20221122135550.GD157542@thinkpad> References: <20221121124400.1282768-1-yoshihiro.shimoda.uh@renesas.com> <20221121124400.1282768-6-yoshihiro.shimoda.uh@renesas.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20221121124400.1282768-6-yoshihiro.shimoda.uh@renesas.com> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org + Serge (who authored EDMA support) Thanks, Mani On Mon, Nov 21, 2022 at 09:43:56PM +0900, Yoshihiro Shimoda wrote: > Since reading value of PCIE_DMA_VIEWPORT_BASE + PCIE_DMA_CTRL was > 0x00000000 on one of SoCs (R-Car S4-8), it cannot find the eDMA. > So, directly read the eDMA register if edma.reg_base is not zero. > > Signed-off-by: Yoshihiro Shimoda > --- > drivers/pci/controller/dwc/pcie-designware.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c > index 637d01807c67..2cc8584da6f4 100644 > --- a/drivers/pci/controller/dwc/pcie-designware.c > +++ b/drivers/pci/controller/dwc/pcie-designware.c > @@ -836,8 +836,7 @@ static int dw_pcie_edma_find_chip(struct dw_pcie *pci) > { > u32 val; > > - val = dw_pcie_readl_dbi(pci, PCIE_DMA_VIEWPORT_BASE + PCIE_DMA_CTRL); > - if (val == 0xFFFFFFFF && pci->edma.reg_base) { > + if (pci->edma.reg_base) { > pci->edma.mf = EDMA_MF_EDMA_UNROLL; > > val = dw_pcie_readl_dma(pci, PCIE_DMA_CTRL); > @@ -845,6 +844,7 @@ static int dw_pcie_edma_find_chip(struct dw_pcie *pci) > pci->edma.mf = EDMA_MF_EDMA_LEGACY; > > pci->edma.reg_base = pci->dbi_base + PCIE_DMA_VIEWPORT_BASE; > + val = dw_pcie_readl_dbi(pci, PCIE_DMA_VIEWPORT_BASE + PCIE_DMA_CTRL); > } else { > return -ENODEV; > } > -- > 2.25.1 > -- மணிவண்ணன் சதாசிவம்