On 6/28/23 06:57, Alexandra Winter wrote:
> The last s390 machine that supported FDDI was z900 ('7th generation',
> released in 2000). The oldest machine generation currently supported by
> the Linux kernel is MARCH_Z10 (released 2008). If there is still a usecase
> for connecting a Linux on s390 instance to a LAN Channel Station (LCS), it
> can only do so via Ethernet.
>
> Randy Dunlap[1] found that LCS over FDDI has never worked, when FDDI
> was compiled as module. Instead of fixing that, remove the FDDI option
> from the lcs driver.
>
> While at it, make the CONFIG_LCS description a bit more helpful.
>
> References:
> [1] https://lore.kernel.org/netdev/20230621213742.8245-1-rdunlap@xxxxxxxxxxxxx/
>
> Signed-off-by: Alexandra Winter <wintera@xxxxxxxxxxxxx>
Reviewed-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Thanks.
> ---
> drivers/s390/net/Kconfig | 5 ++---
> drivers/s390/net/lcs.c | 39 ++++++---------------------------------
> 2 files changed, 8 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/s390/net/Kconfig b/drivers/s390/net/Kconfig
> index 9c67b97faba2..74760c1a163b 100644
> --- a/drivers/s390/net/Kconfig
> +++ b/drivers/s390/net/Kconfig
> @@ -5,12 +5,11 @@ menu "S/390 network device drivers"
> config LCS
> def_tristate m
> prompt "Lan Channel Station Interface"
> - depends on CCW && NETDEVICES && (ETHERNET || FDDI)
> + depends on CCW && NETDEVICES && ETHERNET
> help
> Select this option if you want to use LCS networking on IBM System z.
> - This device driver supports FDDI (IEEE 802.7) and Ethernet.
> To compile as a module, choose M. The module name is lcs.
> - If you do not know what it is, it's safe to choose Y.
> + If you do not use LCS, choose N.
>
> config CTCM
> def_tristate m
> diff --git a/drivers/s390/net/lcs.c b/drivers/s390/net/lcs.c
> index 9fd8e6f07a03..a1f2acd6fb8f 100644
> --- a/drivers/s390/net/lcs.c
> +++ b/drivers/s390/net/lcs.c
> @@ -17,7 +17,6 @@
> #include <linux/if.h>
> #include <linux/netdevice.h>
> #include <linux/etherdevice.h>
> -#include <linux/fddidevice.h>
> #include <linux/inetdevice.h>
> #include <linux/in.h>
> #include <linux/igmp.h>
> @@ -36,10 +35,6 @@
> #include "lcs.h"
>
>
> -#if !defined(CONFIG_ETHERNET) && !defined(CONFIG_FDDI)
> -#error Cannot compile lcs.c without some net devices switched on.
> -#endif
> -
> /*
> * initialization string for output
> */
> @@ -1601,19 +1596,11 @@ lcs_startlan_auto(struct lcs_card *card)
> int rc;
>
> LCS_DBF_TEXT(2, trace, "strtauto");
> -#ifdef CONFIG_ETHERNET
> card->lan_type = LCS_FRAME_TYPE_ENET;
> rc = lcs_send_startlan(card, LCS_INITIATOR_TCPIP);
> if (rc == 0)
> return 0;
>
> -#endif
> -#ifdef CONFIG_FDDI
> - card->lan_type = LCS_FRAME_TYPE_FDDI;
> - rc = lcs_send_startlan(card, LCS_INITIATOR_TCPIP);
> - if (rc == 0)
> - return 0;
> -#endif
> return -EIO;
> }
>
> @@ -1806,22 +1793,16 @@ lcs_get_frames_cb(struct lcs_channel *channel, struct lcs_buffer *buffer)
> card->stats.rx_errors++;
> return;
> }
> - /* What kind of frame is it? */
> - if (lcs_hdr->type == LCS_FRAME_TYPE_CONTROL) {
> - /* Control frame. */
> + if (lcs_hdr->type == LCS_FRAME_TYPE_CONTROL)
> lcs_get_control(card, (struct lcs_cmd *) lcs_hdr);
> - } else if (lcs_hdr->type == LCS_FRAME_TYPE_ENET ||
> - lcs_hdr->type == LCS_FRAME_TYPE_TR ||
> - lcs_hdr->type == LCS_FRAME_TYPE_FDDI) {
> - /* Normal network packet. */
> + else if (lcs_hdr->type == LCS_FRAME_TYPE_ENET)
> lcs_get_skb(card, (char *)(lcs_hdr + 1),
> lcs_hdr->offset - offset -
> sizeof(struct lcs_header));
> - } else {
> - /* Unknown frame type. */
> - ; // FIXME: error message ?
> - }
> - /* Proceed to next frame. */
> + else
> + dev_info_once(&card->dev->dev,
> + "Unknown frame type %d\n",
> + lcs_hdr->type);
> offset = lcs_hdr->offset;
> lcs_hdr->offset = LCS_ILLEGAL_OFFSET;
> lcs_hdr = (struct lcs_header *) (buffer->data + offset);
> @@ -2140,18 +2121,10 @@ lcs_new_device(struct ccwgroup_device *ccwgdev)
> goto netdev_out;
> }
> switch (card->lan_type) {
> -#ifdef CONFIG_ETHERNET
> case LCS_FRAME_TYPE_ENET:
> card->lan_type_trans = eth_type_trans;
> dev = alloc_etherdev(0);
> break;
> -#endif
> -#ifdef CONFIG_FDDI
> - case LCS_FRAME_TYPE_FDDI:
> - card->lan_type_trans = fddi_type_trans;
> - dev = alloc_fddidev(0);
> - break;
> -#endif
> default:
> LCS_DBF_TEXT(3, setup, "errinit");
> pr_err(" Initialization failed\n");
--
~Randy
