net: ethernet: ti: davinci_cpdma: revert "drop frame padding"

This reverts commit 9ffc513 ("net: ethernet: ti: davinci_cpdma: drop
frame padding") which has depndency from not yet merged patch [1] and so
breaks cpsw_new driver.

[1] https://patchwork.kernel.org/project/netdevbpf/patch/20210805145511.12016-1-grygorii.strashko@ti.com/
Fixes: 9ffc513 ("net: ethernet: ti: davinci_cpdma: drop frame padding")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Link: https://lore.kernel.org/r/20210806142809.15069-1-grygorii.strashko@ti.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/ti/cpsw_priv.c

@@ -518,6 +518,7 @@ int cpsw_init_common(struct cpsw_common *cpsw, void __iomem *ss_regs,
 
 	dma_params.num_chan		= data->channels;
 	dma_params.has_soft_reset	= true;
+	dma_params.min_packet_size	= CPSW_MIN_PACKET_SIZE;
 	dma_params.desc_mem_size	= data->bd_ram_size;
 	dma_params.desc_align		= 16;
 	dma_params.has_ext_regs		= true;

drivers/net/ethernet/ti/davinci_cpdma.c

@@ -1034,6 +1034,11 @@ static int cpdma_chan_submit_si(struct submit_info *si)
 		return -ENOMEM;
 	}
 
+	if (len < ctlr->params.min_packet_size) {
+		len = ctlr->params.min_packet_size;
+		chan->stats.runt_transmit_buff++;
+	}
+
 	mode = CPDMA_DESC_OWNER | CPDMA_DESC_SOP | CPDMA_DESC_EOP;
 	cpdma_desc_to_port(chan, mode, si->directed);
 

drivers/net/ethernet/ti/davinci_cpdma.h

@@ -26,6 +26,7 @@ struct cpdma_params {
 	void __iomem		*rxthresh, *rxfree;
 	int			num_chan;
 	bool			has_soft_reset;
+	int			min_packet_size;
 	dma_addr_t		desc_mem_phys;
 	dma_addr_t		desc_hw_addr;
 	int			desc_mem_size;

drivers/net/ethernet/ti/davinci_emac.c

@@ -1850,6 +1850,7 @@ static int davinci_emac_probe(struct platform_device *pdev)
 	dma_params.txcp			= priv->emac_base + 0x640;
 	dma_params.rxcp			= priv->emac_base + 0x660;
 	dma_params.num_chan		= EMAC_MAX_TXRX_CHANNELS;
+	dma_params.min_packet_size	= EMAC_DEF_MIN_ETHPKTSIZE;
 	dma_params.desc_hw_addr		= hw_ram_addr;
 	dma_params.desc_mem_size	= pdata->ctrl_ram_size;
 	dma_params.desc_align		= 16;