netdev - [PATCH net-next v2 2/2] sfc: Implement change of BAR configuration

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Date:   Thu, 07 Jul 2022 14:07:32 +0100
From:   Martin Habets <habetsm.xilinx@...il.com>
To:     davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
        edumazet@...gle.com
Cc:     netdev@...r.kernel.org, ecree.xilinx@...il.com,
        linux-pci@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Subject: [PATCH net-next v2 2/2] sfc: Implement change of BAR configuration

Placeholders are added for vDPA. These will be assigned with
a later patch.

Signed-off-by: Martin Habets <habetsm.xilinx@...il.com>
---
 drivers/net/ethernet/sfc/ef100_nic.c |   39 ++++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/sfc/ef100_nic.c b/drivers/net/ethernet/sfc/ef100_nic.c
index 218db3cb31eb..ce4b7b4e705e 100644
--- a/drivers/net/ethernet/sfc/ef100_nic.c
+++ b/drivers/net/ethernet/sfc/ef100_nic.c
@@ -704,7 +704,25 @@ static unsigned int efx_ef100_recycle_ring_size(const struct efx_nic *efx)
 	return 10 * EFX_RECYCLE_RING_SIZE_10G;
 }
 
-/* BAR configuration */
+/* BAR configuration.
+ * To change BAR configuration we tear down the current configuration (which
+ * leaves the hardware in the PROBED state), and then initialise the new
+ * BAR state.
+ */
+static struct {
+	int (*init)(struct efx_probe_data *probe_data);
+	void (*fini)(struct efx_probe_data *probe_data);
+} bar_config_std[] = {
+	[EF100_BAR_CONFIG_EF100] = {
+		.init = ef100_probe_netdev,
+		.fini = ef100_remove_netdev
+	},
+	[EF100_BAR_CONFIG_VDPA] = {
+		.init = NULL,	/* TODO: assign these */
+		.fini = NULL
+	},
+};
+
 static ssize_t bar_config_show(struct device *dev,
 			       struct device_attribute *attr, char *buf_out)
 {
@@ -732,7 +750,9 @@ static ssize_t bar_config_store(struct device *dev,
 {
 	struct efx_nic *efx = pci_get_drvdata(to_pci_dev(dev));
 	struct ef100_nic_data *nic_data = efx->nic_data;
-	enum ef100_bar_config new_config;
+	enum ef100_bar_config new_config, old_config;
+	struct efx_probe_data *probe_data;
+	int rc;
 
 	if (!strncasecmp(buf, "ef100", min_t(size_t, count, 5)))
 		new_config = EF100_BAR_CONFIG_EF100;
@@ -741,7 +761,22 @@ static ssize_t bar_config_store(struct device *dev,
 	else
 		return -EIO;
 
+	old_config = nic_data->bar_config;
+	if (new_config == old_config)
+		return count;
+
+	probe_data = container_of(efx, struct efx_probe_data, efx);
+	if (bar_config_std[old_config].fini)
+		bar_config_std[old_config].fini(probe_data);
+
 	nic_data->bar_config = new_config;
+	if (bar_config_std[new_config].init) {
+		rc = bar_config_std[new_config].init(probe_data);
+		if (rc)
+			return rc;
+	}
+
+	pci_info(efx->pci_dev, "BAR configuration changed to %s", buf);
 	return count;
 }