Re: [PATCH v13 net-next 09/15] net: mvpp2: enable global flow control

[Russell King - ARM Linux admin]

On Thu, Feb 11, 2021 at 12:48:56PM +0200, stef...@marvell.com wrote:
> +static void mvpp2_cm3_write(struct mvpp2 *priv, u32 offset, u32 data)
> +{
> + writel(data, priv->cm3_base + offset);
> +}
> +
> +static u32 mvpp2_cm3_read(struct mvpp2 *priv, u32 offset)
> +{
> + return readl(priv->cm3_base + offset);
> +}
> +

Would it also make sense to have mvpp2_cm3_modify() ? You seem to be
adding several instances of read-modify-write sequences to CM3 RAM in
your series.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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[PATCH v13 net-next 09/15] net: mvpp2: enable global flow control

[stefanc]

From: Stefan Chulski 

This patch enables global flow control in FW and in the phylink validate mask.

Signed-off-by: Stefan Chulski 
Acked-by: Marcin Wojtas 
---
 drivers/net/ethernet/marvell/mvpp2/mvpp2.h  | 11 +--
 drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 30 +++-
 2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h 
b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
index d2cc513c..8945fb9 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
@@ -763,9 +763,11 @@
((kb) * 1024 - MVPP2_TX_FIFO_THRESHOLD_MIN)
 
 /* MSS Flow control */
-#define FC_QUANTA  0x
-#define FC_CLK_DIVIDER 100
-#define MSS_THRESHOLD_STOP 768
+#define MSS_FC_COM_REG 0
+#define FLOW_CONTROL_ENABLE_BITBIT(0)
+#define FC_QUANTA  0x
+#define FC_CLK_DIVIDER 100
+#define MSS_THRESHOLD_STOP 768
 
 /* RX buffer constants */
 #define MVPP2_SKB_SHINFO_SIZE \
@@ -1017,6 +1019,9 @@ struct mvpp2 {
 
/* page_pool allocator */
struct page_pool *page_pool[MVPP2_PORT_MAX_RXQ];
+
+   /* Global TX Flow Control config */
+   bool global_tx_fc;
 };
 
 struct mvpp2_pcpu_stats {
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c 
b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index 8b4073c..027101b 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -91,6 +91,16 @@ static inline u32 mvpp2_cpu_to_thread(struct mvpp2 *priv, 
int cpu)
return cpu % priv->nthreads;
 }
 
+static void mvpp2_cm3_write(struct mvpp2 *priv, u32 offset, u32 data)
+{
+   writel(data, priv->cm3_base + offset);
+}
+
+static u32 mvpp2_cm3_read(struct mvpp2 *priv, u32 offset)
+{
+   return readl(priv->cm3_base + offset);
+}
+
 static struct page_pool *
 mvpp2_create_page_pool(struct device *dev, int num, int len,
   enum dma_data_direction dma_dir)
@@ -5950,6 +5960,11 @@ static void mvpp2_phylink_validate(struct phylink_config 
*config,
phylink_set(mask, Autoneg);
phylink_set_port_modes(mask);
 
+   if (port->priv->global_tx_fc) {
+   phylink_set(mask, Pause);
+   phylink_set(mask, Asym_Pause);
+   }
+
switch (state->interface) {
case PHY_INTERFACE_MODE_10GBASER:
case PHY_INTERFACE_MODE_XAUI:
@@ -6951,7 +6966,7 @@ static int mvpp2_probe(struct platform_device *pdev)
struct resource *res;
void __iomem *base;
int i, shared;
-   int err;
+   int err, val;
 
priv = devm_kzalloc(>dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
@@ -7003,6 +7018,10 @@ static int mvpp2_probe(struct platform_device *pdev)
err = mvpp2_get_sram(pdev, priv);
if (err)
dev_warn(>dev, "Fail to alloc CM3 SRAM\n");
+
+   /* Enable global Flow Control only if handler to SRAM not NULL 
*/
+   if (priv->cm3_base)
+   priv->global_tx_fc = true;
}
 
if (priv->hw_version != MVPP21 && dev_of_node(>dev)) {
@@ -7168,6 +7187,15 @@ static int mvpp2_probe(struct platform_device *pdev)
goto err_port_probe;
}
 
+   /* Enable global flow control. In this stage global
+* flow control enabled, but still disabled per port.
+*/
+   if (priv->global_tx_fc && priv->hw_version != MVPP21) {
+   val = mvpp2_cm3_read(priv, MSS_FC_COM_REG);
+   val |= FLOW_CONTROL_ENABLE_BIT;
+   mvpp2_cm3_write(priv, MSS_FC_COM_REG, val);
+   }
+
mvpp2_dbgfs_init(priv, pdev->name);
 
platform_set_drvdata(pdev, priv);
-- 
1.9.1