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Subject[PATCH v4 08/11] VAS: Define vas_rx_win_open() interface
Date
Define the vas_rx_win_open() interface. This interface is intended to be
used by the Nest Accelerator (NX) driver(s) to setup receive windows for
one or more NX engines (which implement compression/encryption algorithms
in the hardware).

Follow-on patches will provide an interface to close the window and to open
a send window that kenrel subsystems can use to access the NX engines.

The interface to open a receive window is expected to be invoked for each
instance of VAS in the system.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
---

Changelog[v3]:
- Fault receive windows must enable interrupts and disable
notifications. NX Windows are opposite.
- Use macros rather than enum for threshold-control mode
- Ignore irq_ports for in-kernel windows. They are needed for
user space windows and will be added later
---
arch/powerpc/include/asm/vas.h | 45 ++++++
arch/powerpc/platforms/powernv/vas-window.c | 205 +++++++++++++++++++++++++++-
arch/powerpc/platforms/powernv/vas.h | 11 ++
3 files changed, 260 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.h
index e2575d5..09ea6f7 100644
--- a/arch/powerpc/include/asm/vas.h
+++ b/arch/powerpc/include/asm/vas.h
@@ -31,4 +31,49 @@ enum vas_cop_type {
VAS_COP_TYPE_MAX,
};

+/*
+ * Receive window attributes specified by the (in-kernel) owner of window.
+ */
+struct vas_rx_win_attr {
+ void *rx_fifo;
+ int rx_fifo_size;
+ int wcreds_max;
+
+ bool pin_win;
+ bool rej_no_credit;
+ bool tx_wcred_mode;
+ bool rx_wcred_mode;
+ bool tx_win_ord_mode;
+ bool rx_win_ord_mode;
+ bool data_stamp;
+ bool nx_win;
+ bool fault_win;
+ bool notify_disable;
+ bool intr_disable;
+ bool notify_early;
+
+ int lnotify_lpid;
+ int lnotify_pid;
+ int lnotify_tid;
+ int pswid;
+
+ int tc_mode;
+};
+
+/*
+ * Helper to initialize receive window attributes to defaults for an
+ * NX window.
+ */
+extern void vas_init_rx_win_attr(struct vas_rx_win_attr *rxattr,
+ enum vas_cop_type cop);
+
+/*
+ * Open a VAS receive window for the instance of VAS identified by @vasid
+ * Use @attr to initialize the attributes of the window.
+ *
+ * Return a handle to the window or ERR_PTR() on error.
+ */
+extern struct vas_window *vas_rx_win_open(int vasid, enum vas_cop_type cop,
+ struct vas_rx_win_attr *attr);
+
#endif /* _MISC_VAS_H */
diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c
index 0c178fe..04f6bb2 100644
--- a/arch/powerpc/platforms/powernv/vas-window.c
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -477,7 +477,7 @@ void vas_window_free(struct vas_window *window)
kfree(window);
}

-struct vas_window *vas_window_alloc(struct vas_instance *vinst, int id)
+static struct vas_window *vas_window_alloc(struct vas_instance *vinst, int id)
{
struct vas_window *window;

@@ -503,3 +503,206 @@ int vas_win_close(struct vas_window *window)
{
return -1;
}
+
+struct vas_window *get_vinstance_rxwin(struct vas_instance *vinst,
+ enum vas_cop_type cop)
+{
+ struct vas_window *rxwin;
+
+ mutex_lock(&vinst->mutex);
+
+ rxwin = vinst->rxwin[cop];
+ if (rxwin)
+ atomic_inc(&rxwin->num_txwins);
+
+ mutex_unlock(&vinst->mutex);
+
+ return rxwin;
+}
+
+static void set_vinstance_rxwin(struct vas_instance *vinst,
+ enum vas_cop_type cop, struct vas_window *window)
+{
+ mutex_lock(&vinst->mutex);
+
+ /*
+ * There should only be one receive window for a coprocessor type.
+ */
+ WARN_ON_ONCE(vinst->rxwin[cop]);
+ vinst->rxwin[cop] = window;
+
+ mutex_unlock(&vinst->mutex);
+}
+
+static void init_winctx_for_rxwin(struct vas_window *rxwin,
+ struct vas_rx_win_attr *rxattr,
+ struct vas_winctx *winctx)
+{
+ /*
+ * We first zero (memset()) all fields and only set non-zero fields.
+ * Following fields are 0/false but maybe deserve a comment:
+ *
+ * ->user_win No support for user Rx windows yet
+ * ->notify_os_intr_reg In powerNV, send intrs to HV
+ * ->notify_disable False for NX windows
+ * ->intr_disable False for Fault Windows
+ * ->xtra_write False for NX windows
+ * ->notify_early NA for NX windows
+ * ->rsvd_txbuf_count NA for Rx windows
+ * ->lpid, ->pid, ->tid NA for Rx windows
+ */
+
+ memset(winctx, 0, sizeof(struct vas_winctx));
+
+ winctx->rx_fifo = rxattr->rx_fifo;
+ winctx->rx_fifo_size = rxattr->rx_fifo_size;
+ winctx->wcreds_max = rxattr->wcreds_max ?: VAS_WCREDS_DEFAULT;
+ winctx->pin_win = rxattr->pin_win;
+
+ winctx->nx_win = rxattr->nx_win;
+ winctx->fault_win = rxattr->fault_win;
+ winctx->rx_word_mode = rxattr->rx_win_ord_mode;
+ winctx->tx_word_mode = rxattr->tx_win_ord_mode;
+ winctx->rx_wcred_mode = rxattr->rx_wcred_mode;
+ winctx->tx_wcred_mode = rxattr->tx_wcred_mode;
+
+ winctx->fault_win_id = fault_winid;
+
+ if (winctx->nx_win) {
+ winctx->data_stamp = true;
+ winctx->intr_disable = true;
+ winctx->pin_win = true;
+
+ WARN_ON_ONCE(winctx->fault_win);
+ WARN_ON_ONCE(!winctx->rx_word_mode);
+ WARN_ON_ONCE(!winctx->tx_word_mode);
+ WARN_ON_ONCE(winctx->notify_after_count);
+ } else if (winctx->fault_win) {
+ winctx->notify_disable = true;
+ }
+
+ winctx->lnotify_lpid = rxattr->lnotify_lpid;
+ winctx->lnotify_pid = rxattr->lnotify_pid;
+ winctx->lnotify_tid = rxattr->lnotify_tid;
+ winctx->pswid = rxattr->pswid;
+ winctx->dma_type = VAS_DMA_TYPE_INJECT;
+ winctx->tc_mode = rxattr->tc_mode;
+
+ winctx->min_scope = VAS_SCOPE_LOCAL;
+ winctx->max_scope = VAS_SCOPE_VECTORED_GROUP;
+}
+
+static bool rx_win_args_valid(enum vas_cop_type cop,
+ struct vas_rx_win_attr *attr)
+{
+ dump_rx_win_attr(attr);
+
+ if (cop >= VAS_COP_TYPE_MAX)
+ return false;
+
+ if (attr->rx_fifo_size < VAS_RX_FIFO_SIZE_MIN)
+ return false;
+
+ if (attr->rx_fifo_size > VAS_RX_FIFO_SIZE_MAX)
+ return false;
+
+ if (attr->nx_win) {
+ /* cannot be both fault and nx */
+ if (attr->fault_win)
+ return false;
+ /*
+ * Section 3.1.4.32: NX Windows must not disable notification,
+ * and must not enable interrupts or early notification.
+ */
+ if (attr->notify_disable || !attr->intr_disable ||
+ attr->notify_early)
+ return false;
+ } else if (attr->fault_win) {
+ /*
+ * Section 3.1.4.32: Fault windows must disable notification
+ * but not interrupts.
+ */
+ if (!attr->notify_disable || attr->intr_disable)
+ return false;
+ } else {
+ /* Rx window must be either NX or Fault window for now. */
+ return false;
+ }
+
+ return true;
+}
+
+void vas_init_rx_win_attr(struct vas_rx_win_attr *rxattr, enum vas_cop_type cop)
+{
+ memset(rxattr, 0, sizeof(*rxattr));
+
+ if (cop == VAS_COP_TYPE_842 || cop == VAS_COP_TYPE_842_HIPRI) {
+ rxattr->pin_win = true;
+ rxattr->nx_win = true;
+ rxattr->fault_win = false;
+ rxattr->intr_disable = true;
+ rxattr->rx_wcred_mode = true;
+ rxattr->tx_wcred_mode = true;
+ rxattr->rx_win_ord_mode = true;
+ rxattr->tx_win_ord_mode = true;
+ } else if (cop == VAS_COP_TYPE_FAULT) {
+ rxattr->pin_win = true;
+ rxattr->fault_win = true;
+ rxattr->notify_disable = true;
+ rxattr->rx_wcred_mode = true;
+ rxattr->tx_wcred_mode = true;
+ rxattr->rx_win_ord_mode = true;
+ rxattr->tx_win_ord_mode = true;
+ }
+}
+
+struct vas_window *vas_rx_win_open(int vasid, enum vas_cop_type cop,
+ struct vas_rx_win_attr *rxattr)
+{
+ int rc, winid;
+ struct vas_instance *vinst;
+ struct vas_window *rxwin;
+ struct vas_winctx winctx;
+
+ if (!vas_initialized())
+ return ERR_PTR(-EAGAIN);
+
+ if (!rx_win_args_valid(cop, rxattr))
+ return ERR_PTR(-EINVAL);
+
+ vinst = find_vas_instance(vasid);
+ if (!vinst) {
+ pr_devel("VAS: vasid %d not found!\n", vasid);
+ return ERR_PTR(-EINVAL);
+ }
+ pr_devel("VAS: Found instance %d\n", vasid);
+
+ winid = vas_assign_window_id(&vinst->ida);
+ if (winid < 0)
+ return ERR_PTR(winid);
+
+ rc = -ENOMEM;
+ rxwin = vas_window_alloc(vinst, winid);
+ if (!rxwin) {
+ pr_devel("VAS: Unable to allocate memory for Rx window\n");
+ goto release_winid;
+ }
+
+ rxwin->tx_win = false;
+ rxwin->cop = cop;
+
+ init_winctx_for_rxwin(rxwin, rxattr, &winctx);
+ rxwin->nx_win = winctx.nx_win;
+ init_winctx_regs(rxwin, &winctx);
+
+ set_vinstance_rxwin(vinst, cop, rxwin);
+
+ if (winctx.fault_win)
+ fault_winid = winid;
+
+ return rxwin;
+
+release_winid:
+ vas_release_window_id(&vinst->ida, rxwin->winid);
+ return ERR_PTR(rc);
+}
diff --git a/arch/powerpc/platforms/powernv/vas.h b/arch/powerpc/platforms/powernv/vas.h
index bb7908b..86ed526 100644
--- a/arch/powerpc/platforms/powernv/vas.h
+++ b/arch/powerpc/platforms/powernv/vas.h
@@ -399,6 +399,16 @@ extern struct vas_instance *find_vas_instance(int vasid);
#define VREG(r) VREG_SFX(r, _OFFSET)

#ifdef vas_debug
+static inline void dump_rx_win_attr(struct vas_rx_win_attr *attr)
+{
+ pr_err("VAS: fault %d, notify %d, intr %d early %d\n",
+ attr->fault_win, attr->notify_disable,
+ attr->intr_disable, attr->notify_early);
+
+ pr_err("VAS: rx_fifo_size %d, max value %d\n",
+ attr->rx_fifo_size, VAS_RX_FIFO_SIZE_MAX);
+}
+
static inline void vas_log_write(struct vas_window *win, char *name,
void *regptr, uint64_t val)
{
@@ -411,6 +421,7 @@ static inline void vas_log_write(struct vas_window *win, char *name,
#else /* vas_debug */

#define vas_log_write(win, name, reg, val)
+#define dump_rx_win_attr(attr)

#endif /* vas_debug */

--
2.7.4
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