linux-kernel - [PATCH v4 3/5] PCI: dwc: Pass the eDMA mapping format flag directly from glue drivers

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Message-Id: <20240306-dw-hdma-v4-3-9fed506e95be@linaro.org>
Date: Wed, 06 Mar 2024 15:51:59 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Jingoo Han <jingoohan1@...il.com>, 
 Gustavo Pimentel <gustavo.pimentel@...opsys.com>, 
 Lorenzo Pieralisi <lpieralisi@...nel.org>, 
 Krzysztof Wilczyński <kw@...ux.com>, 
 Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>, 
 Marek Vasut <marek.vasut+renesas@...il.com>, 
 Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>, 
 Kishon Vijay Abraham I <kishon@...nel.org>
Cc: Serge Semin <fancer.lancer@...il.com>, linux-pci@...r.kernel.org, 
 linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org, 
 linux-arm-msm@...r.kernel.org, mhi@...ts.linux.dev, 
 Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>, 
 Siddharth Vadapalli <s-vadapalli@...com>
Subject: [PATCH v4 3/5] PCI: dwc: Pass the eDMA mapping format flag
 directly from glue drivers

Instead of maintaining a separate capability for glue drivers that cannot
support auto detection of the eDMA mapping format, let's pass the mapping
format directly from them.

This will simplify the code and also allow adding HDMA support that also
doesn't support auto detection of mapping format.

Suggested-by: Serge Semin <fancer.lancer@...il.com>
Reviewed-by: Siddharth Vadapalli <s-vadapalli@...com>
Reviewed-by: Serge Semin <fancer.lancer@...il.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
---
 drivers/pci/controller/dwc/pcie-designware.c | 16 +++++++++-------
 drivers/pci/controller/dwc/pcie-designware.h |  5 ++---
 drivers/pci/controller/dwc/pcie-rcar-gen4.c  |  2 +-
 3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 599991b7ffb2..c59b2876e5d4 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -894,18 +894,20 @@ static int dw_pcie_edma_find_mf(struct dw_pcie *pci)
 {
 	u32 val;
 
+	/*
+	 * Bail out finding the mapping format if it is already set by the glue
+	 * driver. Also ensure that the edma.reg_base is pointing to a valid
+	 * memory region.
+	 */
+	if (pci->edma.mf != EDMA_MF_EDMA_LEGACY)
+		return pci->edma.reg_base ? 0 : -ENODEV;
+
 	/*
 	 * Indirect eDMA CSRs access has been completely removed since v5.40a
 	 * thus no space is now reserved for the eDMA channels viewport and
 	 * former DMA CTRL register is no longer fixed to FFs.
-	 *
-	 * Note that Renesas R-Car S4-8's PCIe controllers for unknown reason
-	 * have zeros in the eDMA CTRL register even though the HW-manual
-	 * explicitly states there must FFs if the unrolled mapping is enabled.
-	 * For such cases the low-level drivers are supposed to manually
-	 * activate the unrolled mapping to bypass the auto-detection procedure.
 	 */
-	if (dw_pcie_ver_is_ge(pci, 540A) || dw_pcie_cap_is(pci, EDMA_UNROLL))
+	if (dw_pcie_ver_is_ge(pci, 540A))
 		val = 0xFFFFFFFF;
 	else
 		val = dw_pcie_readl_dbi(pci, PCIE_DMA_VIEWPORT_BASE + PCIE_DMA_CTRL);
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 26dae4837462..995805279021 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -51,9 +51,8 @@
 
 /* DWC PCIe controller capabilities */
 #define DW_PCIE_CAP_REQ_RES		0
-#define DW_PCIE_CAP_EDMA_UNROLL		1
-#define DW_PCIE_CAP_IATU_UNROLL		2
-#define DW_PCIE_CAP_CDM_CHECK		3
+#define DW_PCIE_CAP_IATU_UNROLL		1
+#define DW_PCIE_CAP_CDM_CHECK		2
 
 #define dw_pcie_cap_is(_pci, _cap) \
 	test_bit(DW_PCIE_CAP_ ## _cap, &(_pci)->caps)
diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
index e9166619b1f9..3c535ef5ea91 100644
--- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
+++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
@@ -255,7 +255,7 @@ static struct rcar_gen4_pcie *rcar_gen4_pcie_alloc(struct platform_device *pdev)
 	rcar->dw.ops = &dw_pcie_ops;
 	rcar->dw.dev = dev;
 	rcar->pdev = pdev;
-	dw_pcie_cap_set(&rcar->dw, EDMA_UNROLL);
+	rcar->dw.edma.mf = EDMA_MF_EDMA_UNROLL;
 	dw_pcie_cap_set(&rcar->dw, REQ_RES);
 	platform_set_drvdata(pdev, rcar);
 

-- 
2.25.1