netdev - [PATCH v17 12/22] sfc: get endpoint decoder

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Message-ID: <20250624141355.269056-13-alejandro.lucero-palau@amd.com>
Date: Tue, 24 Jun 2025 15:13:45 +0100
From: <alejandro.lucero-palau@....com>
To: <linux-cxl@...r.kernel.org>, <netdev@...r.kernel.org>,
	<dan.j.williams@...el.com>, <edward.cree@....com>, <davem@...emloft.net>,
	<kuba@...nel.org>, <pabeni@...hat.com>, <edumazet@...gle.com>,
	<dave.jiang@...el.com>
CC: Alejandro Lucero <alucerop@....com>, Martin Habets
	<habetsm.xilinx@...il.com>, Edward Cree <ecree.xilinx@...il.com>, "Jonathan
 Cameron" <Jonathan.Cameron@...wei.com>
Subject: [PATCH v17 12/22] sfc: get endpoint decoder

From: Alejandro Lucero <alucerop@....com>

Use cxl api for getting DPA (Device Physical Address) to use through an
endpoint decoder.

Signed-off-by: Alejandro Lucero <alucerop@....com>
Reviewed-by: Martin Habets <habetsm.xilinx@...il.com>
Acked-by: Edward Cree <ecree.xilinx@...il.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
---
 drivers/net/ethernet/sfc/Kconfig   |  1 +
 drivers/net/ethernet/sfc/efx_cxl.c | 32 +++++++++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/sfc/Kconfig b/drivers/net/ethernet/sfc/Kconfig
index 979f2801e2a8..e959d9b4f4ce 100644
--- a/drivers/net/ethernet/sfc/Kconfig
+++ b/drivers/net/ethernet/sfc/Kconfig
@@ -69,6 +69,7 @@ config SFC_MCDI_LOGGING
 config SFC_CXL
 	bool "Solarflare SFC9100-family CXL support"
 	depends on SFC && CXL_BUS >= SFC
+	depends on CXL_REGION
 	default SFC
 	help
 	  This enables SFC CXL support if the kernel is configuring CXL for
diff --git a/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
index e2d52ed49535..c0adfd99cc78 100644
--- a/drivers/net/ethernet/sfc/efx_cxl.c
+++ b/drivers/net/ethernet/sfc/efx_cxl.c
@@ -22,6 +22,7 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
 {
 	struct efx_nic *efx = &probe_data->efx;
 	struct pci_dev *pci_dev = efx->pci_dev;
+	resource_size_t max_size;
 	struct efx_cxl *cxl;
 	u16 dvsec;
 	int rc;
@@ -86,13 +87,42 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
 		return PTR_ERR(cxl->cxlmd);
 	}
 
+	cxl->endpoint = cxl_acquire_endpoint(cxl->cxlmd);
+	if (IS_ERR(cxl->endpoint))
+		return PTR_ERR(cxl->endpoint);
+
+	cxl->cxlrd = cxl_get_hpa_freespace(cxl->cxlmd, 1,
+					   CXL_DECODER_F_RAM | CXL_DECODER_F_TYPE2,
+					   &max_size);
+
+	if (IS_ERR(cxl->cxlrd)) {
+		pci_err(pci_dev, "cxl_get_hpa_freespace failed\n");
+		rc = PTR_ERR(cxl->cxlrd);
+		goto endpoint_release;
+	}
+
+	if (max_size < EFX_CTPIO_BUFFER_SIZE) {
+		pci_err(pci_dev, "%s: not enough free HPA space %pap < %u\n",
+			__func__, &max_size, EFX_CTPIO_BUFFER_SIZE);
+		rc = -ENOSPC;
+		goto put_root_decoder;
+	}
+
 	probe_data->cxl = cxl;
 
-	return 0;
+	goto endpoint_release;
+
+put_root_decoder:
+	cxl_put_root_decoder(cxl->cxlrd);
+endpoint_release:
+	cxl_release_endpoint(cxl->cxlmd, cxl->endpoint);
+	return rc;
 }
 
 void efx_cxl_exit(struct efx_probe_data *probe_data)
 {
+	if (probe_data->cxl)
+		cxl_put_root_decoder(probe_data->cxl->cxlrd);
 }
 
 MODULE_IMPORT_NS("CXL");
-- 
2.34.1