Subject: Re: [PATCH net-next v3 10/10] net: ti: icssg-prueth: Add ICSSG Ethernet driver for AM65x SR1.0 platforms

From: Simon Horman <[email-masked]>
Date: Thu, 22 Feb 2024 13:31:03 +0000

On Wed, Feb 21, 2024 at 03:24:16PM +0000, Diogo Ivo wrote:
> Add the PRUeth driver for the ICSSG subsystem found in AM65x SR1.0 devices.
> The main differences that set SR1.0 and SR2.0 apart are the missing TXPRU
> core in SR1.0, two extra DMA channels for management purposes and different
> firmware that needs to be configured accordingly.
> 
> Based on the work of Roger Quadros, Vignesh Raghavendra and
> Grygorii Strashko in TI's 5.10 SDK [1].
> 
> [1]: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/?h=ti-linux-5.10.y
> 
> Co-developed-by: Jan Kiszka <[email-masked]>
> Signed-off-by: Jan Kiszka <[email-masked]>
> Signed-off-by: Diogo Ivo <[email-masked]>

...

> diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth_sr1.c b/drivers/net/ethernet/ti/icssg/icssg_prueth_sr1.c

...

> +static void icssg_config_sr1(struct prueth *prueth, struct prueth_emac *emac,
> +			     int slice)
> +{
> +	struct icssg_sr1_config config;
> +	void __iomem *va;
> +	int i, index;
> +
> +	memset(&config, 0, sizeof(config));
> +	config.addr_lo = cpu_to_le32(lower_32_bits(prueth->msmcram.pa));
> +	config.addr_hi = cpu_to_le32(upper_32_bits(prueth->msmcram.pa));
> +	config.num_tx_threads = 0;
> +	config.rx_flow_id = emac->rx_flow_id_base; /* flow id for host port */
> +	config.rx_mgr_flow_id = emac->rx_mgm_flow_id_base; /* for mgm ch */
> +	config.rand_seed = get_random_u32();

Hi Diogo and Jan,

The fields of config above are all __le32.
However the last three lines above assign host byte-order values to these
fields. This does not seem correct.

This is flagged by Sparse along with some problems.
Please ensure that new Sparse warnings are not introduced.

> +
> +	for (i = PRUETH_EMAC_BUF_POOL_START_SR1; i < PRUETH_NUM_BUF_POOLS_SR1; i++) {
> +		index =  i - PRUETH_EMAC_BUF_POOL_START_SR1;
> +		config.tx_buf_sz[i] = cpu_to_le32(emac_egress_buf_pool_size[index]);
> +	}
> +
> +	va = prueth->shram.va + slice * ICSSG_CONFIG_OFFSET_SLICE1;
> +	memcpy_toio(va, &config, sizeof(config));
> +
> +	emac->speed = SPEED_1000;
> +	emac->duplex = DUPLEX_FULL;
> +}
> +
> +static int emac_send_command_sr1(struct prueth_emac *emac, u32 cmd)
> +{
> +	dma_addr_t desc_dma, buf_dma;
> +	struct prueth_tx_chn *tx_chn;
> +	struct cppi5_host_desc_t *first_desc;
> +	u32 *data = emac->cmd_data;
> +	u32 pkt_len = sizeof(emac->cmd_data);
> +	void **swdata;
> +	int ret = 0;
> +	u32 *epib;

In new Networking code please express local variables in reverse xmas tree
order - longest line to shortest.

Something like this (completely untested!):

	struct cppi5_host_desc_t *first_desc;
	u32 pkt_len = sizeof(emac->cmd_data);
	dma_addr_t desc_dma, buf_dma;
	struct prueth_tx_chn *tx_chn;
	u32 *data = emac->cmd_data;
	void **swdata;
	int ret = 0;
	u32 *epib;

There is also one such problem in Patch 06/10.
These problems can be detected using:

	https://github.com/ecree-solarflare/xmastree

...