On Sun, Nov 30, 2025 at 01:03:40AM +0900, Koichiro Den wrote:
> Introduce new mwN_offset configfs attributes to specify memory window
> offsets. This enables mapping multiple windows into a single BAR at
This need update documents. But I am not clear how multiple windows map
into a single BAR, could you please give me an example, how to config
more than 2 memory space to one bar by echo to sys file commands.
Frank
> arbitrary offsets, improving layout flexibility.
>
> Signed-off-by: Koichiro Den <den@valinux.co.jp>
> ---
> drivers/pci/endpoint/functions/pci-epf-vntb.c | 133 ++++++++++++++++--
> 1 file changed, 120 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
> index 6c4c78915970..1ff414703566 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
> @@ -39,6 +39,7 @@
> #include <linux/atomic.h>
> #include <linux/delay.h>
> #include <linux/io.h>
> +#include <linux/log2.h>
> #include <linux/module.h>
> #include <linux/slab.h>
>
> @@ -111,7 +112,8 @@ struct epf_ntb_ctrl {
> u64 addr;
> u64 size;
> u32 num_mws;
> - u32 reserved;
> + u32 mw_offset[MAX_MW];
> + u32 mw_size[MAX_MW];
> u32 spad_offset;
> u32 spad_count;
> u32 db_entry_size;
> @@ -128,6 +130,7 @@ struct epf_ntb {
> u32 db_count;
> u32 spad_count;
> u64 mws_size[MAX_MW];
> + u64 mws_offset[MAX_MW];
> atomic64_t db;
> u32 vbus_number;
> u16 vntb_pid;
> @@ -458,6 +461,8 @@ static int epf_ntb_config_spad_bar_alloc(struct epf_ntb *ntb)
>
> ctrl->spad_count = spad_count;
> ctrl->num_mws = ntb->num_mws;
> + memset(ctrl->mw_offset, 0, sizeof(ctrl->mw_offset));
> + memset(ctrl->mw_size, 0, sizeof(ctrl->mw_size));
> ntb->spad_size = spad_size;
>
> ctrl->db_entry_size = sizeof(u32);
> @@ -689,15 +694,31 @@ static void epf_ntb_db_bar_clear(struct epf_ntb *ntb)
> */
> static int epf_ntb_mw_bar_init(struct epf_ntb *ntb)
> {
> + struct device *dev = &ntb->epf->dev;
> + u64 bar_ends[BAR_5 + 1] = { 0 };
> + unsigned long bars_used = 0;
> + enum pci_barno barno;
> + u64 off, size, end;
> int ret = 0;
> int i;
> - u64 size;
> - enum pci_barno barno;
> - struct device *dev = &ntb->epf->dev;
>
> for (i = 0; i < ntb->num_mws; i++) {
> - size = ntb->mws_size[i];
> barno = ntb->epf_ntb_bar[BAR_MW1 + i];
> + off = ntb->mws_offset[i];
> + size = ntb->mws_size[i];
> + end = off + size;
> + if (end > bar_ends[barno])
> + bar_ends[barno] = end;
> + bars_used |= BIT(barno);
> + }
> +
> + for (barno = BAR_0; barno <= BAR_5; barno++) {
> + if (!(bars_used & BIT(barno)))
> + continue;
> + if (bar_ends[barno] < SZ_4K)
> + size = SZ_4K;
> + else
> + size = roundup_pow_of_two(bar_ends[barno]);
>
> ntb->epf->bar[barno].barno = barno;
> ntb->epf->bar[barno].size = size;
> @@ -713,8 +734,12 @@ static int epf_ntb_mw_bar_init(struct epf_ntb *ntb)
> &ntb->epf->bar[barno]);
> if (ret) {
> dev_err(dev, "MW set failed\n");
> - goto err_alloc_mem;
> + goto err_set_bar;
> }
> + }
> +
> + for (i = 0; i < ntb->num_mws; i++) {
> + size = ntb->mws_size[i];
>
> /* Allocate EPC outbound memory windows to vpci vntb device */
> ntb->vpci_mw_addr[i] = pci_epc_mem_alloc_addr(ntb->epf->epc,
> @@ -723,19 +748,31 @@ static int epf_ntb_mw_bar_init(struct epf_ntb *ntb)
> if (!ntb->vpci_mw_addr[i]) {
> ret = -ENOMEM;
> dev_err(dev, "Failed to allocate source address\n");
> - goto err_set_bar;
> + goto err_alloc_mem;
> }
> }
>
> + for (i = 0; i < ntb->num_mws; i++) {
> + ntb->reg->mw_offset[i] = (u32)ntb->mws_offset[i];
> + ntb->reg->mw_size[i] = (u32)ntb->mws_size[i];
> + }
> +
> return ret;
>
> -err_set_bar:
> - pci_epc_clear_bar(ntb->epf->epc,
> - ntb->epf->func_no,
> - ntb->epf->vfunc_no,
> - &ntb->epf->bar[barno]);
> err_alloc_mem:
> - epf_ntb_mw_bar_clear(ntb, i);
> + while (--i >= 0)
> + pci_epc_mem_free_addr(ntb->epf->epc,
> + ntb->vpci_mw_phy[i],
> + ntb->vpci_mw_addr[i],
> + ntb->mws_size[i]);
> +err_set_bar:
> + while (--barno >= BAR_0)
> + if (bars_used & BIT(barno))
> + pci_epc_clear_bar(ntb->epf->epc,
> + ntb->epf->func_no,
> + ntb->epf->vfunc_no,
> + &ntb->epf->bar[barno]);
> +
> return ret;
> }
>
> @@ -1039,6 +1076,60 @@ static ssize_t epf_ntb_##_name##_store(struct config_item *item, \
> return len; \
> }
>
> +#define EPF_NTB_MW_OFF_R(_name) \
> +static ssize_t epf_ntb_##_name##_show(struct config_item *item, \
> + char *page) \
> +{ \
> + struct config_group *group = to_config_group(item); \
> + struct epf_ntb *ntb = to_epf_ntb(group); \
> + struct device *dev = &ntb->epf->dev; \
> + int win_no, idx; \
> + \
> + if (sscanf(#_name, "mw%d_offset", &win_no) != 1) \
> + return -EINVAL; \
> + \
> + idx = win_no - 1; \
> + if (idx < 0 || idx >= ntb->num_mws) { \
> + dev_err(dev, "MW%d out of range (num_mws=%d)\n", \
> + win_no, ntb->num_mws); \
> + return -EINVAL; \
> + } \
> + \
> + idx = array_index_nospec(idx, ntb->num_mws); \
> + return sprintf(page, "%lld\n", ntb->mws_offset[idx]); \
> +}
> +
> +#define EPF_NTB_MW_OFF_W(_name) \
> +static ssize_t epf_ntb_##_name##_store(struct config_item *item, \
> + const char *page, size_t len) \
> +{ \
> + struct config_group *group = to_config_group(item); \
> + struct epf_ntb *ntb = to_epf_ntb(group); \
> + struct device *dev = &ntb->epf->dev; \
> + int win_no, idx; \
> + u64 val; \
> + int ret; \
> + \
> + ret = kstrtou64(page, 0, &val); \
> + if (ret) \
> + return ret; \
> + \
> + if (sscanf(#_name, "mw%d_offset", &win_no) != 1) \
> + return -EINVAL; \
> + \
> + idx = win_no - 1; \
> + if (idx < 0 || idx >= ntb->num_mws) { \
> + dev_err(dev, "MW%d out of range (num_mws=%d)\n", \
> + win_no, ntb->num_mws); \
> + return -EINVAL; \
> + } \
> + \
> + idx = array_index_nospec(idx, ntb->num_mws); \
> + ntb->mws_offset[idx] = val; \
> + \
> + return len; \
> +}
> +
> #define EPF_NTB_BAR_R(_name, _id) \
> static ssize_t epf_ntb_##_name##_show(struct config_item *item, \
> char *page) \
> @@ -1109,6 +1200,14 @@ EPF_NTB_MW_R(mw3)
> EPF_NTB_MW_W(mw3)
> EPF_NTB_MW_R(mw4)
> EPF_NTB_MW_W(mw4)
> +EPF_NTB_MW_OFF_R(mw1_offset)
> +EPF_NTB_MW_OFF_W(mw1_offset)
> +EPF_NTB_MW_OFF_R(mw2_offset)
> +EPF_NTB_MW_OFF_W(mw2_offset)
> +EPF_NTB_MW_OFF_R(mw3_offset)
> +EPF_NTB_MW_OFF_W(mw3_offset)
> +EPF_NTB_MW_OFF_R(mw4_offset)
> +EPF_NTB_MW_OFF_W(mw4_offset)
> EPF_NTB_BAR_R(ctrl_bar, BAR_CONFIG)
> EPF_NTB_BAR_W(ctrl_bar, BAR_CONFIG)
> EPF_NTB_BAR_R(db_bar, BAR_DB)
> @@ -1129,6 +1228,10 @@ CONFIGFS_ATTR(epf_ntb_, mw1);
> CONFIGFS_ATTR(epf_ntb_, mw2);
> CONFIGFS_ATTR(epf_ntb_, mw3);
> CONFIGFS_ATTR(epf_ntb_, mw4);
> +CONFIGFS_ATTR(epf_ntb_, mw1_offset);
> +CONFIGFS_ATTR(epf_ntb_, mw2_offset);
> +CONFIGFS_ATTR(epf_ntb_, mw3_offset);
> +CONFIGFS_ATTR(epf_ntb_, mw4_offset);
> CONFIGFS_ATTR(epf_ntb_, vbus_number);
> CONFIGFS_ATTR(epf_ntb_, vntb_pid);
> CONFIGFS_ATTR(epf_ntb_, vntb_vid);
> @@ -1147,6 +1250,10 @@ static struct configfs_attribute *epf_ntb_attrs[] = {
> &epf_ntb_attr_mw2,
> &epf_ntb_attr_mw3,
> &epf_ntb_attr_mw4,
> + &epf_ntb_attr_mw1_offset,
> + &epf_ntb_attr_mw2_offset,
> + &epf_ntb_attr_mw3_offset,
> + &epf_ntb_attr_mw4_offset,
> &epf_ntb_attr_vbus_number,
> &epf_ntb_attr_vntb_pid,
> &epf_ntb_attr_vntb_vid,
> --
> 2.48.1
>