Re: [PATCH v3 02/14] soc: ti: k3: add navss ringacc driver

From: Grygorii Strashko <grygorii.strashko@ti.com>

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 I-SCI Message
Protocol supports only one combined operation (allocate+configure).

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Peter Ujfalusi <redacted>
---
 drivers/soc/ti/Kconfig            |   12 +
 drivers/soc/ti/Makefile           |    1 +
 drivers/soc/ti/k3-ringacc.c       | 1165 +++++++++++++++++++++++++++++
 include/linux/soc/ti/k3-ringacc.h |  245 ++++++
 4 files changed, 1423 insertions(+)
 create mode 100644 drivers/soc/ti/k3-ringacc.c
 create mode 100644 include/linux/soc/ti/k3-ringacc.h

diff --git a/drivers/soc/ti/Kconfig b/drivers/soc/ti/Kconfig
index cf545f428d03..87722d33333a 100644
--- a/drivers/soc/ti/Kconfig
+++ b/drivers/soc/ti/Kconfig

@@ -80,6 +80,18 @@ 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
+	tristate "K3 Ring accelerator Sub System"
+	depends on ARCH_K3 || COMPILE_TEST
+	depends on TI_SCI_INTA_IRQCHIP
+	default y
+	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

diff --git a/drivers/soc/ti/Makefile b/drivers/soc/ti/Makefile
index b3868d392d4f..cc4bc8b08bf5 100644
--- a/drivers/soc/ti/Makefile
+++ b/drivers/soc/ti/Makefile

@@ -9,3 +9,4 @@ obj-$(CONFIG_AMX3_PM)			+= pm33xx.o
 obj-$(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

diff --git a/drivers/soc/ti/k3-ringacc.c b/drivers/soc/ti/k3-ringacc.c
new file mode 100644
index 000000000000..4728a79fd2c0
--- /dev/null
+++ b/drivers/soc/ti/k3-ringacc.c

@@ -0,0 +1,1165 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * TI K3 NAVSS Ring Accelerator subsystem driver
+ *
+ * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/soc/ti/k3-ringacc.h>
+#include <linux/soc/ti/ti_sci_protocol.h>
+#include <linux/soc/ti/ti_sci_inta_msi.h>
+#include <linux/of_irq.h>
+#include <linux/irqdomain.h>
+
+static LIST_HEAD(k3_ringacc_list);
+static DEFINE_MUTEX(k3_ringacc_list_lock);
+
+#define K3_RINGACC_CFG_RING_SIZE_ELCNT_MASK		GENMASK(19, 0)
+
+/**
+ * struct k3_ring_rt_regs -  The RA Control/Status Registers region
+ */
+struct k3_ring_rt_regs {
+	u32	resv_16[4];
+	u32	db;		/* RT Ring N Doorbell Register */
+	u32	resv_4[1];
+	u32	occ;		/* RT Ring N Occupancy Register */
+	u32	indx;		/* RT Ring N Current Index Register */
+	u32	hwocc;		/* RT Ring N Hardware Occupancy Register */
+	u32	hwindx;		/* RT Ring N Current Index Register */
+};
+
+#define K3_RINGACC_RT_REGS_STEP	0x1000
+
+/**
+ * struct k3_ring_fifo_regs -  The Ring Accelerator Queues Registers region
+ */
+struct k3_ring_fifo_regs {
+	u32	head_data[128];		/* Ring Head Entry Data Registers */
+	u32	tail_data[128];		/* Ring Tail Entry Data Registers */
+	u32	peek_head_data[128];	/* Ring Peek Head Entry Data Regs */
+	u32	peek_tail_data[128];	/* Ring Peek Tail Entry Data Regs */
+};
+
+/**
+ * struct k3_ringacc_proxy_gcfg_regs - RA Proxy Global Config MMIO Region
+ */
+struct k3_ringacc_proxy_gcfg_regs {
+	u32	revision;	/* Revision Register */
+	u32	config;		/* Config Register */
+};
+
+#define K3_RINGACC_PROXY_CFG_THREADS_MASK		GENMASK(15, 0)
+
+/**
+ * struct k3_ringacc_proxy_target_regs -  Proxy Datapath MMIO Region
+ */
+struct k3_ringacc_proxy_target_regs {
+	u32	control;	/* Proxy Control Register */
+	u32	status;		/* Proxy Status Register */
+	u8	resv_512[504];
+	u32	data[128];	/* Proxy Data Register */
+};
+
+#define K3_RINGACC_PROXY_TARGET_STEP	0x1000
+#define K3_RINGACC_PROXY_NOT_USED	(-1)
+
+enum k3_ringacc_proxy_access_mode {
+	PROXY_ACCESS_MODE_HEAD = 0,
+	PROXY_ACCESS_MODE_TAIL = 1,
+	PROXY_ACCESS_MODE_PEEK_HEAD = 2,
+	PROXY_ACCESS_MODE_PEEK_TAIL = 3,
+};
+
+#define K3_RINGACC_FIFO_WINDOW_SIZE_BYTES  (512U)
+#define K3_RINGACC_FIFO_REGS_STEP	0x1000
+#define K3_RINGACC_MAX_DB_RING_CNT    (127U)
+
+/**
+ * struct k3_ring_ops -  Ring operations
+ */
+struct k3_ring_ops {
+	int (*push_tail)(struct k3_ring *ring, void *elm);
+	int (*push_head)(struct k3_ring *ring, void *elm);
+	int (*pop_tail)(struct k3_ring *ring, void *elm);
+	int (*pop_head)(struct k3_ring *ring, void *elm);
+};
+
+/**
+ * struct k3_ring - RA Ring descriptor
+ *
+ * @rt - Ring control/status registers
+ * @fifos - Ring queues registers
+ * @proxy - Ring Proxy Datapath registers
+ * @ring_mem_dma - Ring buffer dma address
+ * @ring_mem_virt - Ring buffer virt address
+ * @ops - Ring operations
+ * @size - Ring size in elements
+ * @elm_size - Size of the ring element
+ * @mode - Ring mode
+ * @flags - flags
+ * @free - Number of free elements
+ * @occ - Ring occupancy
+ * @windex - Write index (only for @K3_RINGACC_RING_MODE_RING)
+ * @rindex - Read index (only for @K3_RINGACC_RING_MODE_RING)
+ * @ring_id - Ring Id
+ * @parent - Pointer on struct @k3_ringacc
+ * @use_count - Use count for shared rings
+ * @proxy_id - RA Ring Proxy Id (only if @K3_RINGACC_RING_USE_PROXY)
+ */
+struct k3_ring {
+	struct k3_ring_rt_regs __iomem *rt;
+	struct k3_ring_fifo_regs __iomem *fifos;
+	struct k3_ringacc_proxy_target_regs  __iomem *proxy;
+	dma_addr_t	ring_mem_dma;
+	void		*ring_mem_virt;
+	struct k3_ring_ops *ops;
+	u32		size;
+	enum k3_ring_size elm_size;
+	enum k3_ring_mode mode;
+	u32		flags;
+#define K3_RING_FLAG_BUSY	BIT(1)
+#define K3_RING_FLAG_SHARED	BIT(2)
+	u32		free;
+	u32		occ;
+	u32		windex;
+	u32		rindex;
+	u32		ring_id;
+	struct k3_ringacc	*parent;
+	u32		use_count;
+	int		proxy_id;
+};
+
+/**
+ * struct k3_ringacc - Rings accelerator descriptor
+ *
+ * @dev - pointer on RA device
+ * @proxy_gcfg - RA proxy global config registers
+ * @proxy_target_base - RA proxy datapath region
+ * @num_rings - number of ring in RA
+ * @rings_inuse - bitfield for ring usage tracking
+ * @rm_gp_range - general purpose rings range from tisci
+ * @dma_ring_reset_quirk - DMA reset w/a enable
+ * @num_proxies - number of RA proxies
+ * @proxy_inuse - bitfield for proxy usage tracking
+ * @rings - array of rings descriptors (struct @k3_ring)
+ * @list - list of RAs in the system
+ * @tisci - pointer ti-sci handle
+ * @tisci_ring_ops - ti-sci rings ops
+ * @tisci_dev_id - ti-sci device id
+ */
+struct k3_ringacc {
+	struct device *dev;
+	struct k3_ringacc_proxy_gcfg_regs __iomem *proxy_gcfg;
+	void __iomem *proxy_target_base;
+	u32 num_rings; /* number of rings in Ringacc module */
+	unsigned long *rings_inuse;
+	struct ti_sci_resource *rm_gp_range;
+
+	bool dma_ring_reset_quirk;
+	u32 num_proxies;
+	unsigned long *proxy_inuse;
+
+	struct k3_ring *rings;
+	struct list_head list;
+	struct mutex req_lock; /* protect rings allocation */
+
+	const struct ti_sci_handle *tisci;
+	const struct ti_sci_rm_ringacc_ops *tisci_ring_ops;
+	u32  tisci_dev_id;

diff --git a/include/linux/soc/ti/k3-ringacc.h b/include/linux/soc/ti/k3-ringacc.h
new file mode 100644
index 000000000000..526b2e38fcce
--- /dev/null
+++ b/include/linux/soc/ti/k3-ringacc.h

@@ -0,0 +1,245 @@
+/* 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;
+