soc: ti: k3: add navss ringacc driver

The Ring Accelerator (RINGACC or RA) provides hardware acceleration to
enable straightforward passing of work between a producer and a consumer.
There is one RINGACC module per NAVSS on TI AM65x SoCs.

The RINGACC converts constant-address read and write accesses to equivalent
read or write accesses to a circular data structure in memory. The RINGACC
eliminates the need for each DMA controller which needs to access ring
elements from having to know the current state of the ring (base address,
current offset). The DMA controller performs a read or write access to a
specific address range (which maps to the source interface on the RINGACC)
and the RINGACC replaces the address for the transaction with a new address
which corresponds to the head or tail element of the ring (head for reads,
tail for writes). Since the RINGACC maintains the state, multiple DMA
controllers or channels are allowed to coherently share the same rings as
applicable. The RINGACC is able to place data which is destined towards
software into cached memory directly.

Supported ring modes:
- Ring Mode
- Messaging Mode
- Credentials Mode
- Queue Manager Mode

TI-SCI integration:

Texas Instrument's System Control Interface (TI-SCI) Message Protocol now
has control over Ringacc module resources management (RM) and Rings
configuration.

The corresponding support of TI-SCI Ringacc module RM protocol
introduced as option through DT parameters:
- ti,sci: phandle on TI-SCI firmware controller DT node
- ti,sci-dev-id: TI-SCI device identifier as per TI-SCI firmware spec

if both parameters present - Ringacc driver will configure/free/reset Rings
using TI-SCI Message Ringacc RM Protocol.

The Ringacc driver manages Rings allocation by itself now and requests
TI-SCI firmware to allocate and configure specific Rings only. It's done
this way because, Linux driver implements two stage Rings allocation and
configuration (allocate ring and configure ring) while TI-SCI Message
Protocol supports only one combined operation (allocate+configure).

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Tero Kristo <t-kristo@ti.com>
Tested-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>

drivers/soc/ti/Kconfig

@@ -80,6 +80,17 @@ config TI_SCI_PM_DOMAINS
 	  called ti_sci_pm_domains. Note this is needed early in boot before
 	  rootfs may be available.
 
+config TI_K3_RINGACC
+	bool "K3 Ring accelerator Sub System"
+	depends on ARCH_K3 || COMPILE_TEST
+	depends on TI_SCI_INTA_IRQCHIP
+	help
+	  Say y here to support the K3 Ring accelerator module.
+	  The Ring Accelerator (RINGACC or RA)  provides hardware acceleration
+	  to enable straightforward passing of work between a producer
+	  and a consumer. There is one RINGACC module per NAVSS on TI AM65x SoCs
+	  If unsure, say N.
+
 endif # SOC_TI
 
 config TI_SCI_INTA_MSI_DOMAIN

drivers/soc/ti/Makefile

@@ -10,3 +10,4 @@ obj-$(CONFIG_ARCH_OMAP2PLUS)		+= omap_prm.o
 obj-$(CONFIG_WKUP_M3_IPC)		+= wkup_m3_ipc.o
 obj-$(CONFIG_TI_SCI_PM_DOMAINS)		+= ti_sci_pm_domains.o
 obj-$(CONFIG_TI_SCI_INTA_MSI_DOMAIN)	+= ti_sci_inta_msi.o
+obj-$(CONFIG_TI_K3_RINGACC)		+= k3-ringacc.o

include/linux/soc/ti/k3-ringacc.h

@@ -0,0 +1,244 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * K3 Ring Accelerator (RA) subsystem interface
+ *
+ * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com
+ */
+
+#ifndef __SOC_TI_K3_RINGACC_API_H_
+#define __SOC_TI_K3_RINGACC_API_H_
+
+#include <linux/types.h>
+
+struct device_node;
+
+/**
+ * enum k3_ring_mode - &struct k3_ring_cfg mode
+ *
+ * RA ring operational modes
+ *
+ * @K3_RINGACC_RING_MODE_RING: Exposed Ring mode for SW direct access
+ * @K3_RINGACC_RING_MODE_MESSAGE: Messaging mode. Messaging mode requires
+ *	that all accesses to the queue must go through this IP so that all
+ *	accesses to the memory are controlled and ordered. This IP then
+ *	controls the entire state of the queue, and SW has no directly control,
+ *	such as through doorbells and cannot access the storage memory directly.
+ *	This is particularly useful when more than one SW or HW entity can be
+ *	the producer and/or consumer at the same time
+ * @K3_RINGACC_RING_MODE_CREDENTIALS: Credentials mode is message mode plus
+ *	stores credentials with each message, requiring the element size to be
+ *	doubled to fit the credentials. Any exposed memory should be protected
+ *	by a firewall from unwanted access
+ */
+enum k3_ring_mode {
+	K3_RINGACC_RING_MODE_RING = 0,
+	K3_RINGACC_RING_MODE_MESSAGE,
+	K3_RINGACC_RING_MODE_CREDENTIALS,
+	K3_RINGACC_RING_MODE_INVALID
+};
+
+/**
+ * enum k3_ring_size - &struct k3_ring_cfg elm_size
+ *
+ * RA ring element's sizes in bytes.
+ */
+enum k3_ring_size {
+	K3_RINGACC_RING_ELSIZE_4 = 0,
+	K3_RINGACC_RING_ELSIZE_8,
+	K3_RINGACC_RING_ELSIZE_16,
+	K3_RINGACC_RING_ELSIZE_32,
+	K3_RINGACC_RING_ELSIZE_64,
+	K3_RINGACC_RING_ELSIZE_128,
+	K3_RINGACC_RING_ELSIZE_256,
+	K3_RINGACC_RING_ELSIZE_INVALID
+};
+
+struct k3_ringacc;
+struct k3_ring;
+
+/**
+ * enum k3_ring_cfg - RA ring configuration structure
+ *
+ * @size: Ring size, number of elements
+ * @elm_size: Ring element size
+ * @mode: Ring operational mode
+ * @flags: Ring configuration flags. Possible values:
+ *	 @K3_RINGACC_RING_SHARED: when set allows to request the same ring
+ *	 few times. It's usable when the same ring is used as Free Host PD ring
+ *	 for different flows, for example.
+ *	 Note: Locking should be done by consumer if required
+ */
+struct k3_ring_cfg {
+	u32 size;
+	enum k3_ring_size elm_size;
+	enum k3_ring_mode mode;
+#define K3_RINGACC_RING_SHARED BIT(1)
+	u32 flags;
+};
+
+#define K3_RINGACC_RING_ID_ANY (-1)
+
+/**
+ * of_k3_ringacc_get_by_phandle - find a RA by phandle property
+ * @np: device node
+ * @propname: property name containing phandle on RA node
+ *
+ * Returns pointer on the RA - struct k3_ringacc
+ * or -ENODEV if not found,
+ * or -EPROBE_DEFER if not yet registered
+ */
+struct k3_ringacc *of_k3_ringacc_get_by_phandle(struct device_node *np,
+						const char *property);
+
+#define K3_RINGACC_RING_USE_PROXY BIT(1)
+
+/**
+ * k3_ringacc_request_ring - request ring from ringacc
+ * @ringacc: pointer on ringacc
+ * @id: ring id or K3_RINGACC_RING_ID_ANY for any general purpose ring
+ * @flags:
+ *	@K3_RINGACC_RING_USE_PROXY: if set - proxy will be allocated and
+ *		used to access ring memory. Sopported only for rings in
+ *		Message/Credentials/Queue mode.
+ *
+ * Returns pointer on the Ring - struct k3_ring
+ * or NULL in case of failure.
+ */
+struct k3_ring *k3_ringacc_request_ring(struct k3_ringacc *ringacc,
+					int id, u32 flags);
+
+/**
+ * k3_ringacc_ring_reset - ring reset
+ * @ring: pointer on Ring
+ *
+ * Resets ring internal state ((hw)occ, (hw)idx).
+ */
+void k3_ringacc_ring_reset(struct k3_ring *ring);
+/**
+ * k3_ringacc_ring_reset - ring reset for DMA rings
+ * @ring: pointer on Ring
+ *
+ * Resets ring internal state ((hw)occ, (hw)idx). Should be used for rings
+ * which are read by K3 UDMA, like TX or Free Host PD rings.
+ */
+void k3_ringacc_ring_reset_dma(struct k3_ring *ring, u32 occ);
+
+/**
+ * k3_ringacc_ring_free - ring free
+ * @ring: pointer on Ring
+ *
+ * Resets ring and free all alocated resources.
+ */
+int k3_ringacc_ring_free(struct k3_ring *ring);
+
+/**
+ * k3_ringacc_get_ring_id - Get the Ring ID
+ * @ring: pointer on ring
+ *
+ * Returns the Ring ID
+ */
+u32 k3_ringacc_get_ring_id(struct k3_ring *ring);
+
+/**
+ * k3_ringacc_get_ring_irq_num - Get the irq number for the ring
+ * @ring: pointer on ring
+ *
+ * Returns the interrupt number which can be used to request the interrupt
+ */
+int k3_ringacc_get_ring_irq_num(struct k3_ring *ring);
+
+/**
+ * k3_ringacc_ring_cfg - ring configure
+ * @ring: pointer on ring
+ * @cfg: Ring configuration parameters (see &struct k3_ring_cfg)
+ *
+ * Configures ring, including ring memory allocation.
+ * Returns 0 on success, errno otherwise.
+ */
+int k3_ringacc_ring_cfg(struct k3_ring *ring, struct k3_ring_cfg *cfg);
+
+/**
+ * k3_ringacc_ring_get_size - get ring size
+ * @ring: pointer on ring
+ *
+ * Returns ring size in number of elements.
+ */
+u32 k3_ringacc_ring_get_size(struct k3_ring *ring);
+
+/**
+ * k3_ringacc_ring_get_free - get free elements
+ * @ring: pointer on ring
+ *
+ * Returns number of free elements in the ring.
+ */
+u32 k3_ringacc_ring_get_free(struct k3_ring *ring);
+
+/**
+ * k3_ringacc_ring_get_occ - get ring occupancy
+ * @ring: pointer on ring
+ *
+ * Returns total number of valid entries on the ring
+ */
+u32 k3_ringacc_ring_get_occ(struct k3_ring *ring);
+
+/**
+ * k3_ringacc_ring_is_full - checks if ring is full
+ * @ring: pointer on ring
+ *
+ * Returns true if the ring is full
+ */
+u32 k3_ringacc_ring_is_full(struct k3_ring *ring);
+
+/**
+ * k3_ringacc_ring_push - push element to the ring tail
+ * @ring: pointer on ring
+ * @elem: pointer on ring element buffer
+ *
+ * Push one ring element to the ring tail. Size of the ring element is
+ * determined by ring configuration &struct k3_ring_cfg elm_size.
+ *
+ * Returns 0 on success, errno otherwise.
+ */
+int k3_ringacc_ring_push(struct k3_ring *ring, void *elem);
+
+/**
+ * k3_ringacc_ring_pop - pop element from the ring head
+ * @ring: pointer on ring
+ * @elem: pointer on ring element buffer
+ *
+ * Push one ring element from the ring head. Size of the ring element is
+ * determined by ring configuration &struct k3_ring_cfg elm_size..
+ *
+ * Returns 0 on success, errno otherwise.
+ */
+int k3_ringacc_ring_pop(struct k3_ring *ring, void *elem);
+
+/**
+ * k3_ringacc_ring_push_head - push element to the ring head
+ * @ring: pointer on ring
+ * @elem: pointer on ring element buffer
+ *
+ * Push one ring element to the ring head. Size of the ring element is
+ * determined by ring configuration &struct k3_ring_cfg elm_size.
+ *
+ * Returns 0 on success, errno otherwise.
+ * Not Supported by ring modes: K3_RINGACC_RING_MODE_RING
+ */
+int k3_ringacc_ring_push_head(struct k3_ring *ring, void *elem);
+
+/**
+ * k3_ringacc_ring_pop_tail - pop element from the ring tail
+ * @ring: pointer on ring
+ * @elem: pointer on ring element buffer
+ *
+ * Push one ring element from the ring tail. Size of the ring element is
+ * determined by ring configuration &struct k3_ring_cfg elm_size.
+ *
+ * Returns 0 on success, errno otherwise.
+ * Not Supported by ring modes: K3_RINGACC_RING_MODE_RING
+ */
+int k3_ringacc_ring_pop_tail(struct k3_ring *ring, void *elem);
+
+u32 k3_ringacc_get_tisci_dev_id(struct k3_ring *ring);
+
+#endif /* __SOC_TI_K3_RINGACC_API_H_ */