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Subject: Re: [PATCH v2 02/14] soc: ti: k3: add navss ringacc driver
To:     Peter Ujfalusi <peter.ujfalusi@ti.com>, <vkoul@kernel.org>,
        <robh+dt@kernel.org>, <nm@ti.com>, <ssantosh@kernel.org>
CC:     <dan.j.williams@intel.com>, <dmaengine@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <grygorii.strashko@ti.com>, <lokeshvutla@ti.com>,
        <tony@atomide.com>, <j-keerthy@ti.com>
References: <20190730093450.12664-1-peter.ujfalusi@ti.com>
 <20190730093450.12664-3-peter.ujfalusi@ti.com>
From:   Tero Kristo <t-kristo@ti.com>
Message-ID: <13e5c02f-7060-3a30-56cb-a9caca9fc85b@ti.com>
Date:   Mon, 9 Sep 2019 09:09:02 +0300
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Hi,

Mostly some cosmetic comments below, other than that seems fine to me.

On 30/07/2019 12:34, Peter Ujfalusi wrote:
> 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

I-SCI should be TI-SCI I believe.

> Protocol supports only one combined operation (allocate+configure).
> 
> Grygorii Strashko <grygorii.strashko@ti.com>

Above seems to be missing SoB?

> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> ---
>   drivers/soc/ti/Kconfig            |   17 +
>   drivers/soc/ti/Makefile           |    1 +
>   drivers/soc/ti/k3-ringacc.c       | 1191 +++++++++++++++++++++++++++++
>   include/linux/soc/ti/k3-ringacc.h |  262 +++++++
>   4 files changed, 1471 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..10c76faa503e 100644
> --- a/drivers/soc/ti/Kconfig
> +++ b/drivers/soc/ti/Kconfig
> @@ -80,6 +80,23 @@ 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.
> +
> +config TI_K3_RINGACC_DEBUG
> +	tristate "K3 Ring accelerator Sub System tests and debug"
> +	depends on TI_K3_RINGACC
> +	default 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..401dfc963319
> --- /dev/null
> +++ b/drivers/soc/ti/k3-ringacc.c
> @@ -0,0 +1,1191 @@
> +// 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);
> +
> +#ifdef CONFIG_TI_K3_RINGACC_DEBUG
> +#define	k3_nav_dbg(dev, arg...) dev_err(dev, arg)

dev_err seems exaggeration for debug purposes, maybe just dev_info.

> +static	void dbg_writel(u32 v, void __iomem *reg)
> +{
> +	pr_err("WRITEL(32): v(%08X)-->reg(%p)\n", v, reg);

Again, maybe just pr_info.

> +	writel(v, reg);
> +}
> +
> +static	u32 dbg_readl(void __iomem *reg)
> +{
> +	u32 v;
> +
> +	v = readl(reg);
> +	pr_err("READL(32): v(%08X)<--reg(%p)\n", v, reg);
> +	return v;
> +}
> +#else
> +#define	k3_nav_dbg(dev, arg...) dev_dbg(dev, arg)
> +#define dbg_writel(v, reg) writel(v, reg)

Do you need to use hard writel, writel_relaxed is not enough?

> +
> +#define dbg_readl(reg) readl(reg)

Same as above but for read?

> +#endif
> +
> +#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
> + * @rm_gp_range - general purpose rings range from tisci
> + * @dma_ring_reset_quirk - DMA reset w/a enable
> + * @num_proxies - number of RA proxies
> + * @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;

proxy_inuse is not documented above.

> +
> +	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;
> +};
> +
> +static long k3_ringacc_ring_get_fifo_pos(struct k3_ring *ring)
> +{
> +	return K3_RINGACC_FIFO_WINDOW_SIZE_BYTES -
> +	       (4 << ring->elm_size);
> +}
> +
> +static void *k3_ringacc_get_elm_addr(struct k3_ring *ring, u32 idx)
> +{
> +	return (idx * (4 << ring->elm_size) + ring->ring_mem_virt);

The arithmetic here seems backwards compared to most other code I've 
seen. It would be more readable if you have it like:

ring->ring_mem_virt + idx * (4 << ring->elm_size);

> +}
> +
> +static int k3_ringacc_ring_push_mem(struct k3_ring *ring, void *elem);
> +static int k3_ringacc_ring_pop_mem(struct k3_ring *ring, void *elem);
> +
> +static struct k3_ring_ops k3_ring_mode_ring_ops = {
> +		.push_tail = k3_ringacc_ring_push_mem,
> +		.pop_head = k3_ringacc_ring_pop_mem,
> +};
> +
> +static int k3_ringacc_ring_push_io(struct k3_ring *ring, void *elem);
> +static int k3_ringacc_ring_pop_io(struct k3_ring *ring, void *elem);
> +static int k3_ringacc_ring_push_head_io(struct k3_ring *ring, void *elem);
> +static int k3_ringacc_ring_pop_tail_io(struct k3_ring *ring, void *elem);
> +
> +static struct k3_ring_ops k3_ring_mode_msg_ops = {
> +		.push_tail = k3_ringacc_ring_push_io,
> +		.push_head = k3_ringacc_ring_push_head_io,
> +		.pop_tail = k3_ringacc_ring_pop_tail_io,
> +		.pop_head = k3_ringacc_ring_pop_io,
> +};
> +
> +static int k3_ringacc_ring_push_head_proxy(struct k3_ring *ring, void *elem);
> +static int k3_ringacc_ring_push_tail_proxy(struct k3_ring *ring, void *elem);
> +static int k3_ringacc_ring_pop_head_proxy(struct k3_ring *ring, void *elem);
> +static int k3_ringacc_ring_pop_tail_proxy(struct k3_ring *ring, void *elem);
> +
> +static struct k3_ring_ops k3_ring_mode_proxy_ops = {
> +		.push_tail = k3_ringacc_ring_push_tail_proxy,
> +		.push_head = k3_ringacc_ring_push_head_proxy,
> +		.pop_tail = k3_ringacc_ring_pop_tail_proxy,
> +		.pop_head = k3_ringacc_ring_pop_head_proxy,
> +};
> +
> +#ifdef CONFIG_TI_K3_RINGACC_DEBUG
> +void k3_ringacc_ring_dump(struct k3_ring *ring)
> +{
> +	struct device *dev = ring->parent->dev;
> +
> +	k3_nav_dbg(dev, "dump ring: %d\n", ring->ring_id);
> +	k3_nav_dbg(dev, "dump mem virt %p, dma %pad\n",
> +		   ring->ring_mem_virt, &ring->ring_mem_dma);
> +	k3_nav_dbg(dev, "dump elmsize %d, size %d, mode %d, proxy_id %d\n",
> +		   ring->elm_size, ring->size, ring->mode, ring->proxy_id);
> +
> +	k3_nav_dbg(dev, "dump ring_rt_regs: db%08x\n",
> +		   readl(&ring->rt->db));

Why not use readl_relaxed in this func?

> +	k3_nav_dbg(dev, "dump occ%08x\n",
> +		   readl(&ring->rt->occ));
> +	k3_nav_dbg(dev, "dump indx%08x\n",
> +		   readl(&ring->rt->indx));
> +	k3_nav_dbg(dev, "dump hwocc%08x\n",
> +		   readl(&ring->rt->hwocc));
> +	k3_nav_dbg(dev, "dump hwindx%08x\n",
> +		   readl(&ring->rt->hwindx));
> +
> +	if (ring->ring_mem_virt)
> +		print_hex_dump(KERN_ERR, "dump ring_mem_virt ",
> +			       DUMP_PREFIX_NONE, 16, 1,
> +			       ring->ring_mem_virt, 16 * 8, false);
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_dump);

Do you really need to export a debug function?

> +#endif
> +
> +struct k3_ring *k3_ringacc_request_ring(struct k3_ringacc *ringacc,
> +					int id, u32 flags)
> +{
> +	int proxy_id = K3_RINGACC_PROXY_NOT_USED;
> +
> +	mutex_lock(&ringacc->req_lock);
> +
> +	if (id == K3_RINGACC_RING_ID_ANY) {
> +		/* Request for any general purpose ring */
> +		struct ti_sci_resource_desc *gp_rings =
> +						&ringacc->rm_gp_range->desc[0];
> +		unsigned long size;
> +
> +		size = gp_rings->start + gp_rings->num;
> +		id = find_next_zero_bit(ringacc->rings_inuse, size,
> +					gp_rings->start);
> +		if (id == size)
> +			goto error;
> +	} else if (id < 0) {
> +		goto error;
> +	}
> +
> +	if (test_bit(id, ringacc->rings_inuse) &&
> +	    !(ringacc->rings[id].flags & K3_RING_FLAG_SHARED))
> +		goto error;
> +	else if (ringacc->rings[id].flags & K3_RING_FLAG_SHARED)
> +		goto out;
> +
> +	if (flags & K3_RINGACC_RING_USE_PROXY) {
> +		proxy_id = find_next_zero_bit(ringacc->proxy_inuse,
> +					      ringacc->num_proxies, 0);
> +		if (proxy_id == ringacc->num_proxies)
> +			goto error;
> +	}
> +
> +	if (!try_module_get(ringacc->dev->driver->owner))
> +		goto error;
> +
> +	if (proxy_id != K3_RINGACC_PROXY_NOT_USED) {
> +		set_bit(proxy_id, ringacc->proxy_inuse);
> +		ringacc->rings[id].proxy_id = proxy_id;
> +		k3_nav_dbg(ringacc->dev, "Giving ring#%d proxy#%d\n",
> +			   id, proxy_id);
> +	} else {
> +		k3_nav_dbg(ringacc->dev, "Giving ring#%d\n", id);
> +	}
> +
> +	set_bit(id, ringacc->rings_inuse);
> +out:
> +	ringacc->rings[id].use_count++;
> +	mutex_unlock(&ringacc->req_lock);
> +	return &ringacc->rings[id];
> +
> +error:
> +	mutex_unlock(&ringacc->req_lock);
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_request_ring);
> +
> +static void k3_ringacc_ring_reset_sci(struct k3_ring *ring)
> +{
> +	struct k3_ringacc *ringacc = ring->parent;
> +	int ret;
> +
> +	ret = ringacc->tisci_ring_ops->config(
> +			ringacc->tisci,
> +			TI_SCI_MSG_VALUE_RM_RING_COUNT_VALID,
> +			ringacc->tisci_dev_id,
> +			ring->ring_id,
> +			0,
> +			0,
> +			ring->size,
> +			0,
> +			0,
> +			0);
> +	if (ret)
> +		dev_err(ringacc->dev, "TISCI reset ring fail (%d) ring_idx %d\n",
> +			ret, ring->ring_id);

Return value of sci ops is masked, why not return it and let the caller 
handle it properly?

Same comment for anything similar that follows.

> +}
> +
> +void k3_ringacc_ring_reset(struct k3_ring *ring)
> +{
> +	if (!ring || !(ring->flags & K3_RING_FLAG_BUSY))
> +		return;
> +
> +	ring->occ = 0;
> +	ring->free = 0;
> +	ring->rindex = 0;
> +	ring->windex = 0;
> +
> +	k3_ringacc_ring_reset_sci(ring);
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_reset);
> +
> +static void k3_ringacc_ring_reconfig_qmode_sci(struct k3_ring *ring,
> +					       enum k3_ring_mode mode)
> +{
> +	struct k3_ringacc *ringacc = ring->parent;
> +	int ret;
> +
> +	ret = ringacc->tisci_ring_ops->config(
> +			ringacc->tisci,
> +			TI_SCI_MSG_VALUE_RM_RING_MODE_VALID,
> +			ringacc->tisci_dev_id,
> +			ring->ring_id,
> +			0,
> +			0,
> +			0,
> +			mode,
> +			0,
> +			0);
> +	if (ret)
> +		dev_err(ringacc->dev, "TISCI reconf qmode fail (%d) ring_idx %d\n",
> +			ret, ring->ring_id);
>+}
> +
> +void k3_ringacc_ring_reset_dma(struct k3_ring *ring, u32 occ)
> +{
> +	if (!ring || !(ring->flags & K3_RING_FLAG_BUSY))
> +		return;
> +
> +	if (!ring->parent->dma_ring_reset_quirk)
> +		return;
> +
> +	if (!occ)
> +		occ = dbg_readl(&ring->rt->occ);
> +
> +	if (occ) {
> +		u32 db_ring_cnt, db_ring_cnt_cur;
> +
> +		k3_nav_dbg(ring->parent->dev, "%s %u occ: %u\n", __func__,
> +			   ring->ring_id, occ);
> +		/* 2. Reset the ring */

2? Where is 1?

> +		k3_ringacc_ring_reset_sci(ring);
> +
> +		/*
> +		 * 3. Setup the ring in ring/doorbell mode
> +		 * (if not already in this mode)
> +		 */
> +		if (ring->mode != K3_RINGACC_RING_MODE_RING)
> +			k3_ringacc_ring_reconfig_qmode_sci(
> +					ring, K3_RINGACC_RING_MODE_RING);
> +		/*
> +		 * 4. Ring the doorbell 2**22 – ringOcc times.
> +		 * This will wrap the internal UDMAP ring state occupancy
> +		 * counter (which is 21-bits wide) to 0.
> +		 */
> +		db_ring_cnt = (1U << 22) - occ;
> +
> +		while (db_ring_cnt != 0) {
> +			/*
> +			 * Ring the doorbell with the maximum count each
> +			 * iteration if possible to minimize the total
> +			 * of writes
> +			 */
> +			if (db_ring_cnt > K3_RINGACC_MAX_DB_RING_CNT)
> +				db_ring_cnt_cur = K3_RINGACC_MAX_DB_RING_CNT;
> +			else
> +				db_ring_cnt_cur = db_ring_cnt;
> +
> +			writel(db_ring_cnt_cur, &ring->rt->db);
> +			db_ring_cnt -= db_ring_cnt_cur;
> +		}
> +
> +		/* 5. Restore the original ring mode (if not ring mode) */
> +		if (ring->mode != K3_RINGACC_RING_MODE_RING)
> +			k3_ringacc_ring_reconfig_qmode_sci(ring, ring->mode);
> +	}
> +
> +	/* 2. Reset the ring */

Again 2?

> +	k3_ringacc_ring_reset(ring);
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_reset_dma);
> +
> +static void k3_ringacc_ring_free_sci(struct k3_ring *ring)
> +{
> +	struct k3_ringacc *ringacc = ring->parent;
> +	int ret;
> +
> +	ret = ringacc->tisci_ring_ops->config(
> +			ringacc->tisci,
> +			TI_SCI_MSG_VALUE_RM_ALL_NO_ORDER,
> +			ringacc->tisci_dev_id,
> +			ring->ring_id,
> +			0,
> +			0,
> +			0,
> +			0,
> +			0,
> +			0);
> +	if (ret)
> +		dev_err(ringacc->dev, "TISCI ring free fail (%d) ring_idx %d\n",
> +			ret, ring->ring_id);
> +}
> +
> +int k3_ringacc_ring_free(struct k3_ring *ring)
> +{
> +	struct k3_ringacc *ringacc;
> +
> +	if (!ring)
> +		return -EINVAL;
> +
> +	ringacc = ring->parent;
> +
> +	k3_nav_dbg(ring->parent->dev, "flags: 0x%08x\n", ring->flags);
> +
> +	if (!test_bit(ring->ring_id, ringacc->rings_inuse))
> +		return -EINVAL;
> +
> +	mutex_lock(&ringacc->req_lock);
> +
> +	if (--ring->use_count)
> +		goto out;
> +
> +	if (!(ring->flags & K3_RING_FLAG_BUSY))
> +		goto no_init;
> +
> +	k3_ringacc_ring_free_sci(ring);
> +
> +	dma_free_coherent(ringacc->dev,
> +			  ring->size * (4 << ring->elm_size),
> +			  ring->ring_mem_virt, ring->ring_mem_dma);
> +	ring->flags = 0;
> +	ring->ops = NULL;
> +	if (ring->proxy_id != K3_RINGACC_PROXY_NOT_USED) {
> +		clear_bit(ring->proxy_id, ringacc->proxy_inuse);
> +		ring->proxy = NULL;
> +		ring->proxy_id = K3_RINGACC_PROXY_NOT_USED;
> +	}
> +
> +no_init:
> +	clear_bit(ring->ring_id, ringacc->rings_inuse);
> +
> +	module_put(ringacc->dev->driver->owner);
> +
> +out:
> +	mutex_unlock(&ringacc->req_lock);
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_free);
> +
> +u32 k3_ringacc_get_ring_id(struct k3_ring *ring)
> +{
> +	if (!ring)
> +		return -EINVAL;
> +
> +	return ring->ring_id;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_get_ring_id);
> +
> +u32 k3_ringacc_get_tisci_dev_id(struct k3_ring *ring)
> +{
> +	if (!ring)
> +		return -EINVAL;
> +

What if parent is NULL? Can it ever be here?

> +	return ring->parent->tisci_dev_id;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_get_tisci_dev_id);
> +
> +int k3_ringacc_get_ring_irq_num(struct k3_ring *ring)
> +{
> +	int irq_num;
> +
> +	if (!ring)
> +		return -EINVAL;
> +
> +	irq_num = ti_sci_inta_msi_get_virq(ring->parent->dev, ring->ring_id);
> +	if (irq_num <= 0)
> +		irq_num = -EINVAL;
> +	return irq_num;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_get_ring_irq_num);
> +
> +static int k3_ringacc_ring_cfg_sci(struct k3_ring *ring)
> +{
> +	struct k3_ringacc *ringacc = ring->parent;
> +	u32 ring_idx;
> +	int ret;
> +
> +	if (!ringacc->tisci)
> +		return -EINVAL;
> +
> +	ring_idx = ring->ring_id;
> +	ret = ringacc->tisci_ring_ops->config(
> +			ringacc->tisci,
> +			TI_SCI_MSG_VALUE_RM_ALL_NO_ORDER,
> +			ringacc->tisci_dev_id,
> +			ring_idx,
> +			lower_32_bits(ring->ring_mem_dma),
> +			upper_32_bits(ring->ring_mem_dma),
> +			ring->size,
> +			ring->mode,
> +			ring->elm_size,
> +			0);
> +	if (ret)
> +		dev_err(ringacc->dev, "TISCI config ring fail (%d) ring_idx %d\n",
> +			ret, ring_idx);
> +
> +	return ret;
> +}
> +
> +int k3_ringacc_ring_cfg(struct k3_ring *ring, struct k3_ring_cfg *cfg)
> +{
> +	struct k3_ringacc *ringacc = ring->parent;
> +	int ret = 0;
> +
> +	if (!ring || !cfg)
> +		return -EINVAL;
> +	if (cfg->elm_size > K3_RINGACC_RING_ELSIZE_256 ||
> +	    cfg->mode > K3_RINGACC_RING_MODE_QM ||
> +	    cfg->size & ~K3_RINGACC_CFG_RING_SIZE_ELCNT_MASK ||
> +	    !test_bit(ring->ring_id, ringacc->rings_inuse))
> +		return -EINVAL;
> +
> +	if (ring->use_count != 1)

Hmm, isn't this a failure actually?

> +		return 0;
> +
> +	ring->size = cfg->size;
> +	ring->elm_size = cfg->elm_size;
> +	ring->mode = cfg->mode;
> +	ring->occ = 0;
> +	ring->free = 0;
> +	ring->rindex = 0;
> +	ring->windex = 0;
> +
> +	if (ring->proxy_id != K3_RINGACC_PROXY_NOT_USED)
> +		ring->proxy = ringacc->proxy_target_base +
> +			      ring->proxy_id * K3_RINGACC_PROXY_TARGET_STEP;
> +
> +	switch (ring->mode) {
> +	case K3_RINGACC_RING_MODE_RING:
> +		ring->ops = &k3_ring_mode_ring_ops;
> +		break;
> +	case K3_RINGACC_RING_MODE_QM:
> +		/*
> +		 * In Queue mode elm_size can be 8 only and each operation
> +		 * uses 2 element slots
> +		 */
> +		if (cfg->elm_size != K3_RINGACC_RING_ELSIZE_8 ||
> +		    cfg->size % 2)
> +			goto err_free_proxy;
> +		/* else, fall through */
> +	case K3_RINGACC_RING_MODE_MESSAGE:
> +		if (ring->proxy)
> +			ring->ops = &k3_ring_mode_proxy_ops;
> +		else
> +			ring->ops = &k3_ring_mode_msg_ops;
> +		break;
> +	default:
> +		ring->ops = NULL;
> +		ret = -EINVAL;
> +		goto err_free_proxy;
> +	};
> +
> +	ring->ring_mem_virt =
> +			dma_alloc_coherent(ringacc->dev,
> +					   ring->size * (4 << ring->elm_size),
> +					   &ring->ring_mem_dma, GFP_KERNEL);
> +	if (!ring->ring_mem_virt) {
> +		dev_err(ringacc->dev, "Failed to alloc ring mem\n");
> +		ret = -ENOMEM;
> +		goto err_free_ops;
> +	}
> +
> +	ret = k3_ringacc_ring_cfg_sci(ring);
> +
> +	if (ret)
> +		goto err_free_mem;
> +
> +	ring->flags |= K3_RING_FLAG_BUSY;
> +	ring->flags |= (cfg->flags & K3_RINGACC_RING_SHARED) ?
> +			K3_RING_FLAG_SHARED : 0;
> +
> +	k3_ringacc_ring_dump(ring);
> +
> +	return 0;
> +
> +err_free_mem:
> +	dma_free_coherent(ringacc->dev,
> +			  ring->size * (4 << ring->elm_size),
> +			  ring->ring_mem_virt,
> +			  ring->ring_mem_dma);
> +err_free_ops:
> +	ring->ops = NULL;
> +err_free_proxy:
> +	ring->proxy = NULL;
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_cfg);
> +
> +u32 k3_ringacc_ring_get_size(struct k3_ring *ring)
> +{
> +	if (!ring || !(ring->flags & K3_RING_FLAG_BUSY))
> +		return -EINVAL;
> +
> +	return ring->size;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_get_size);
> +
> +u32 k3_ringacc_ring_get_free(struct k3_ring *ring)
> +{
> +	if (!ring || !(ring->flags & K3_RING_FLAG_BUSY))
> +		return -EINVAL;
> +
> +	if (!ring->free)
> +		ring->free = ring->size - dbg_readl(&ring->rt->occ);
> +
> +	return ring->free;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_get_free);
> +
> +u32 k3_ringacc_ring_get_occ(struct k3_ring *ring)
> +{
> +	if (!ring || !(ring->flags & K3_RING_FLAG_BUSY))
> +		return -EINVAL;
> +
> +	return dbg_readl(&ring->rt->occ);
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_get_occ);
> +
> +u32 k3_ringacc_ring_is_full(struct k3_ring *ring)
> +{
> +	return !k3_ringacc_ring_get_free(ring);
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_is_full);
> +
> +enum k3_ringacc_access_mode {
> +	K3_RINGACC_ACCESS_MODE_PUSH_HEAD,
> +	K3_RINGACC_ACCESS_MODE_POP_HEAD,
> +	K3_RINGACC_ACCESS_MODE_PUSH_TAIL,
> +	K3_RINGACC_ACCESS_MODE_POP_TAIL,
> +	K3_RINGACC_ACCESS_MODE_PEEK_HEAD,
> +	K3_RINGACC_ACCESS_MODE_PEEK_TAIL,
> +};
> +
> +static int k3_ringacc_ring_cfg_proxy(struct k3_ring *ring,
> +				     enum k3_ringacc_proxy_access_mode mode)
> +{
> +	u32 val;
> +
> +	val = ring->ring_id;
> +	val |= mode << 16;
> +	val |= ring->elm_size << 24;

Would be nice to have these magic shifts as defines.

> +	dbg_writel(val, &ring->proxy->control);
> +	return 0;
> +}
> +
> +static int k3_ringacc_ring_access_proxy(struct k3_ring *ring, void *elem,
> +					enum k3_ringacc_access_mode access_mode)
> +{
> +	void __iomem *ptr;
> +
> +	ptr = (void __iomem *)&ring->proxy->data;
> +
> +	switch (access_mode) {
> +	case K3_RINGACC_ACCESS_MODE_PUSH_HEAD:
> +	case K3_RINGACC_ACCESS_MODE_POP_HEAD:
> +		k3_ringacc_ring_cfg_proxy(ring, PROXY_ACCESS_MODE_HEAD);
> +		break;
> +	case K3_RINGACC_ACCESS_MODE_PUSH_TAIL:
> +	case K3_RINGACC_ACCESS_MODE_POP_TAIL:
> +		k3_ringacc_ring_cfg_proxy(ring, PROXY_ACCESS_MODE_TAIL);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ptr += k3_ringacc_ring_get_fifo_pos(ring);
> +
> +	switch (access_mode) {
> +	case K3_RINGACC_ACCESS_MODE_POP_HEAD:
> +	case K3_RINGACC_ACCESS_MODE_POP_TAIL:
> +		k3_nav_dbg(ring->parent->dev, "proxy:memcpy_fromio(x): --> ptr(%p), mode:%d\n",
> +			   ptr, access_mode);
> +		memcpy_fromio(elem, ptr, (4 << ring->elm_size));
> +		ring->occ--;
> +		break;
> +	case K3_RINGACC_ACCESS_MODE_PUSH_TAIL:
> +	case K3_RINGACC_ACCESS_MODE_PUSH_HEAD:
> +		k3_nav_dbg(ring->parent->dev, "proxy:memcpy_toio(x): --> ptr(%p), mode:%d\n",
> +			   ptr, access_mode);
> +		memcpy_toio(ptr, elem, (4 << ring->elm_size));
> +		ring->free--;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	k3_nav_dbg(ring->parent->dev, "proxy: free%d occ%d\n",
> +		   ring->free, ring->occ);
> +	return 0;
> +}
> +
> +static int k3_ringacc_ring_push_head_proxy(struct k3_ring *ring, void *elem)
> +{
> +	return k3_ringacc_ring_access_proxy(ring, elem,
> +					    K3_RINGACC_ACCESS_MODE_PUSH_HEAD);
> +}
> +
> +static int k3_ringacc_ring_push_tail_proxy(struct k3_ring *ring, void *elem)
> +{
> +	return k3_ringacc_ring_access_proxy(ring, elem,
> +					    K3_RINGACC_ACCESS_MODE_PUSH_TAIL);
> +}
> +
> +static int k3_ringacc_ring_pop_head_proxy(struct k3_ring *ring, void *elem)
> +{
> +	return k3_ringacc_ring_access_proxy(ring, elem,
> +					    K3_RINGACC_ACCESS_MODE_POP_HEAD);
> +}
> +
> +static int k3_ringacc_ring_pop_tail_proxy(struct k3_ring *ring, void *elem)
> +{
> +	return k3_ringacc_ring_access_proxy(ring, elem,
> +					    K3_RINGACC_ACCESS_MODE_POP_HEAD);
> +}
> +
> +static int k3_ringacc_ring_access_io(struct k3_ring *ring, void *elem,
> +				     enum k3_ringacc_access_mode access_mode)
> +{
> +	void __iomem *ptr;
> +
> +	switch (access_mode) {
> +	case K3_RINGACC_ACCESS_MODE_PUSH_HEAD:
> +	case K3_RINGACC_ACCESS_MODE_POP_HEAD:
> +		ptr = (void __iomem *)&ring->fifos->head_data;
> +		break;
> +	case K3_RINGACC_ACCESS_MODE_PUSH_TAIL:
> +	case K3_RINGACC_ACCESS_MODE_POP_TAIL:
> +		ptr = (void __iomem *)&ring->fifos->tail_data;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ptr += k3_ringacc_ring_get_fifo_pos(ring);
> +
> +	switch (access_mode) {
> +	case K3_RINGACC_ACCESS_MODE_POP_HEAD:
> +	case K3_RINGACC_ACCESS_MODE_POP_TAIL:
> +		k3_nav_dbg(ring->parent->dev, "memcpy_fromio(x): --> ptr(%p), mode:%d\n",
> +			   ptr, access_mode);
> +		memcpy_fromio(elem, ptr, (4 << ring->elm_size));
> +		ring->occ--;
> +		break;
> +	case K3_RINGACC_ACCESS_MODE_PUSH_TAIL:
> +	case K3_RINGACC_ACCESS_MODE_PUSH_HEAD:
> +		k3_nav_dbg(ring->parent->dev, "memcpy_toio(x): --> ptr(%p), mode:%d\n",
> +			   ptr, access_mode);
> +		memcpy_toio(ptr, elem, (4 << ring->elm_size));
> +		ring->free--;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	k3_nav_dbg(ring->parent->dev, "free%d index%d occ%d index%d\n",
> +		   ring->free, ring->windex, ring->occ, ring->rindex);
> +	return 0;
> +}
> +
> +static int k3_ringacc_ring_push_head_io(struct k3_ring *ring, void *elem)
> +{
> +	return k3_ringacc_ring_access_io(ring, elem,
> +					 K3_RINGACC_ACCESS_MODE_PUSH_HEAD);
> +}
> +
> +static int k3_ringacc_ring_push_io(struct k3_ring *ring, void *elem)
> +{
> +	return k3_ringacc_ring_access_io(ring, elem,
> +					 K3_RINGACC_ACCESS_MODE_PUSH_TAIL);
> +}
> +
> +static int k3_ringacc_ring_pop_io(struct k3_ring *ring, void *elem)
> +{
> +	return k3_ringacc_ring_access_io(ring, elem,
> +					 K3_RINGACC_ACCESS_MODE_POP_HEAD);
> +}
> +
> +static int k3_ringacc_ring_pop_tail_io(struct k3_ring *ring, void *elem)
> +{
> +	return k3_ringacc_ring_access_io(ring, elem,
> +					 K3_RINGACC_ACCESS_MODE_POP_HEAD);
> +}
> +
> +static int k3_ringacc_ring_push_mem(struct k3_ring *ring, void *elem)
> +{
> +	void *elem_ptr;
> +
> +	elem_ptr = k3_ringacc_get_elm_addr(ring, ring->windex);
> +
> +	memcpy(elem_ptr, elem, (4 << ring->elm_size));
> +
> +	ring->windex = (ring->windex + 1) % ring->size;
> +	ring->free--;
> +	dbg_writel(1, &ring->rt->db);
> +
> +	k3_nav_dbg(ring->parent->dev, "ring_push_mem: free%d index%d\n",
> +		   ring->free, ring->windex);
> +
> +	return 0;
> +}
> +
> +static int k3_ringacc_ring_pop_mem(struct k3_ring *ring, void *elem)
> +{
> +	void *elem_ptr;
> +
> +	elem_ptr = k3_ringacc_get_elm_addr(ring, ring->rindex);
> +
> +	memcpy(elem, elem_ptr, (4 << ring->elm_size));
> +
> +	ring->rindex = (ring->rindex + 1) % ring->size;
> +	ring->occ--;
> +	dbg_writel(-1, &ring->rt->db);
> +
> +	k3_nav_dbg(ring->parent->dev, "ring_pop_mem: occ%d index%d pos_ptr%p\n",
> +		   ring->occ, ring->rindex, elem_ptr);
> +	return 0;
> +}
> +
> +int k3_ringacc_ring_push(struct k3_ring *ring, void *elem)
> +{
> +	int ret = -EOPNOTSUPP;
> +
> +	if (!ring || !(ring->flags & K3_RING_FLAG_BUSY))
> +		return -EINVAL;
> +
> +	k3_nav_dbg(ring->parent->dev, "ring_push: free%d index%d\n",
> +		   ring->free, ring->windex);
> +
> +	if (k3_ringacc_ring_is_full(ring))
> +		return -ENOMEM;
> +
> +	if (ring->ops && ring->ops->push_tail)
> +		ret = ring->ops->push_tail(ring, elem);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_push);
> +
> +int k3_ringacc_ring_push_head(struct k3_ring *ring, void *elem)
> +{
> +	int ret = -EOPNOTSUPP;
> +
> +	if (!ring || !(ring->flags & K3_RING_FLAG_BUSY))
> +		return -EINVAL;
> +
> +	k3_nav_dbg(ring->parent->dev, "ring_push_head: free%d index%d\n",
> +		   ring->free, ring->windex);
> +
> +	if (k3_ringacc_ring_is_full(ring))
> +		return -ENOMEM;
> +
> +	if (ring->ops && ring->ops->push_head)
> +		ret = ring->ops->push_head(ring, elem);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_push_head);
> +
> +int k3_ringacc_ring_pop(struct k3_ring *ring, void *elem)
> +{
> +	int ret = -EOPNOTSUPP;
> +
> +	if (!ring || !(ring->flags & K3_RING_FLAG_BUSY))
> +		return -EINVAL;
> +
> +	if (!ring->occ)
> +		ring->occ = k3_ringacc_ring_get_occ(ring);
> +
> +	k3_nav_dbg(ring->parent->dev, "ring_pop: occ%d index%d\n",
> +		   ring->occ, ring->rindex);
> +
> +	if (!ring->occ)
> +		return -ENODATA;
> +
> +	if (ring->ops && ring->ops->pop_head)
> +		ret = ring->ops->pop_head(ring, elem);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_pop);
> +
> +int k3_ringacc_ring_pop_tail(struct k3_ring *ring, void *elem)
> +{
> +	int ret = -EOPNOTSUPP;
> +
> +	if (!ring || !(ring->flags & K3_RING_FLAG_BUSY))
> +		return -EINVAL;
> +
> +	if (!ring->occ)
> +		ring->occ = k3_ringacc_ring_get_occ(ring);
> +
> +	k3_nav_dbg(ring->parent->dev, "ring_pop_tail: occ%d index%d\n",
> +		   ring->occ, ring->rindex);
> +
> +	if (!ring->occ)
> +		return -ENODATA;
> +
> +	if (ring->ops && ring->ops->pop_tail)
> +		ret = ring->ops->pop_tail(ring, elem);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(k3_ringacc_ring_pop_tail);
> +
> +struct k3_ringacc *of_k3_ringacc_get_by_phandle(struct device_node *np,
> +						const char *property)
> +{
> +	struct device_node *ringacc_np;
> +	struct k3_ringacc *ringacc = ERR_PTR(-EPROBE_DEFER);
> +	struct k3_ringacc *entry;
> +
> +	ringacc_np = of_parse_phandle(np, property, 0);
> +	if (!ringacc_np)
> +		return ERR_PTR(-ENODEV);
> +
> +	mutex_lock(&k3_ringacc_list_lock);
> +	list_for_each_entry(entry, &k3_ringacc_list, list)
> +		if (entry->dev->of_node == ringacc_np) {
> +			ringacc = entry;
> +			break;
> +		}
> +	mutex_unlock(&k3_ringacc_list_lock);
> +	of_node_put(ringacc_np);
> +
> +	return ringacc;
> +}
> +EXPORT_SYMBOL_GPL(of_k3_ringacc_get_by_phandle);
> +
> +static int k3_ringacc_probe_dt(struct k3_ringacc *ringacc)
> +{
> +	struct device_node *node = ringacc->dev->of_node;
> +	struct device *dev = ringacc->dev;
> +	struct platform_device *pdev = to_platform_device(dev);
> +	int ret;
> +
> +	if (!node) {
> +		dev_err(dev, "device tree info unavailable\n");
> +		return -ENODEV;
> +	}
> +
> +	ret = of_property_read_u32(node, "ti,num-rings", &ringacc->num_rings);
> +	if (ret) {
> +		dev_err(dev, "ti,num-rings read failure %d\n", ret);
> +		return ret;
> +	}
> +
> +	ringacc->dma_ring_reset_quirk =
> +			of_property_read_bool(node, "ti,dma-ring-reset-quirk");
> +
> +	ringacc->tisci = ti_sci_get_by_phandle(node, "ti,sci");
> +	if (IS_ERR(ringacc->tisci)) {
> +		ret = PTR_ERR(ringacc->tisci);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(dev, "ti,sci read fail %d\n", ret);
> +		ringacc->tisci = NULL;
> +		return ret;
> +	}
> +
> +	ret = of_property_read_u32(node, "ti,sci-dev-id",
> +				   &ringacc->tisci_dev_id);
> +	if (ret) {
> +		dev_err(dev, "ti,sci-dev-id read fail %d\n", ret);
> +		return ret;
> +	}
> +
> +	pdev->id = ringacc->tisci_dev_id;
> +
> +	ringacc->rm_gp_range = devm_ti_sci_get_of_resource(ringacc->tisci, dev,
> +						ringacc->tisci_dev_id,
> +						"ti,sci-rm-range-gp-rings");
> +	if (IS_ERR(ringacc->rm_gp_range)) {
> +		dev_err(dev, "Failed to allocate MSI interrupts\n");
> +		return PTR_ERR(ringacc->rm_gp_range);
> +	}
> +
> +	return ti_sci_inta_msi_domain_alloc_irqs(ringacc->dev,
> +						 ringacc->rm_gp_range);
> +}
> +
> +static int k3_ringacc_probe(struct platform_device *pdev)
> +{
> +	struct k3_ringacc *ringacc;
> +	void __iomem *base_fifo, *base_rt;
> +	struct device *dev = &pdev->dev;
> +	struct resource *res;
> +	int ret, i;
> +
> +	ringacc = devm_kzalloc(dev, sizeof(*ringacc), GFP_KERNEL);
> +	if (!ringacc)
> +		return -ENOMEM;
> +
> +	ringacc->dev = dev;
> +	mutex_init(&ringacc->req_lock);
> +
> +	dev->msi_domain = of_msi_get_domain(dev, dev->of_node,
> +					    DOMAIN_BUS_TI_SCI_INTA_MSI);
> +	if (!dev->msi_domain) {
> +		dev_err(dev, "Failed to get MSI domain\n");
> +		return -EPROBE_DEFER;
> +	}
> +
> +	ret = k3_ringacc_probe_dt(ringacc);
> +	if (ret)
> +		return ret;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rt");
> +	base_rt = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(base_rt))
> +		return PTR_ERR(base_rt);
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "fifos");
> +	base_fifo = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(base_fifo))
> +		return PTR_ERR(base_fifo);
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "proxy_gcfg");
> +	ringacc->proxy_gcfg = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(ringacc->proxy_gcfg))
> +		return PTR_ERR(ringacc->proxy_gcfg);
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> +					   "proxy_target");
> +	ringacc->proxy_target_base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(ringacc->proxy_target_base))
> +		return PTR_ERR(ringacc->proxy_target_base);
> +
> +	ringacc->num_proxies = dbg_readl(&ringacc->proxy_gcfg->config) &
> +					 K3_RINGACC_PROXY_CFG_THREADS_MASK;
> +
> +	ringacc->rings = devm_kzalloc(dev,
> +				      sizeof(*ringacc->rings) *
> +				      ringacc->num_rings,
> +				      GFP_KERNEL);
> +	ringacc->rings_inuse = devm_kcalloc(dev,
> +					    BITS_TO_LONGS(ringacc->num_rings),
> +					    sizeof(unsigned long), GFP_KERNEL);
> +	ringacc->proxy_inuse = devm_kcalloc(dev,
> +					    BITS_TO_LONGS(ringacc->num_proxies),
> +					    sizeof(unsigned long), GFP_KERNEL);
> +
> +	if (!ringacc->rings || !ringacc->rings_inuse || !ringacc->proxy_inuse)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < ringacc->num_rings; i++) {
> +		ringacc->rings[i].rt = base_rt +
> +				       K3_RINGACC_RT_REGS_STEP * i;
> +		ringacc->rings[i].fifos = base_fifo +
> +					  K3_RINGACC_FIFO_REGS_STEP * i;
> +		ringacc->rings[i].parent = ringacc;
> +		ringacc->rings[i].ring_id = i;
> +		ringacc->rings[i].proxy_id = K3_RINGACC_PROXY_NOT_USED;
> +	}
> +	dev_set_drvdata(dev, ringacc);
> +
> +	ringacc->tisci_ring_ops = &ringacc->tisci->ops.rm_ring_ops;
> +
> +	pm_runtime_enable(dev);
> +	ret = pm_runtime_get_sync(dev);
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(dev);
> +		dev_err(dev, "Failed to enable pm %d\n", ret);
> +		goto err;
> +	}
> +
> +	mutex_lock(&k3_ringacc_list_lock);
> +	list_add_tail(&ringacc->list, &k3_ringacc_list);
> +	mutex_unlock(&k3_ringacc_list_lock);
> +
> +	dev_info(dev, "Ring Accelerator probed rings:%u, gp-rings[%u,%u] sci-dev-id:%u\n",
> +		 ringacc->num_rings,
> +		 ringacc->rm_gp_range->desc[0].start,
> +		 ringacc->rm_gp_range->desc[0].num,
> +		 ringacc->tisci_dev_id);
> +	dev_info(dev, "dma-ring-reset-quirk: %s\n",
> +		 ringacc->dma_ring_reset_quirk ? "enabled" : "disabled");
> +	dev_info(dev, "RA Proxy rev. %08x, num_proxies:%u\n",
> +		 dbg_readl(&ringacc->proxy_gcfg->revision),
> +		 ringacc->num_proxies);
> +	return 0;
> +
> +err:
> +	pm_runtime_disable(dev);
> +	return ret;
> +}
> +
> +static int k3_ringacc_remove(struct platform_device *pdev)
> +{
> +	struct k3_ringacc *ringacc = dev_get_drvdata(&pdev->dev);
> +
> +	pm_runtime_put_sync(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
> +
> +	mutex_lock(&k3_ringacc_list_lock);
> +	list_del(&ringacc->list);
> +	mutex_unlock(&k3_ringacc_list_lock);
> +	return 0;
> +}
> +
> +/* Match table for of_platform binding */
> +static const struct of_device_id k3_ringacc_of_match[] = {
> +	{ .compatible = "ti,am654-navss-ringacc", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, k3_ringacc_of_match);
> +
> +static struct platform_driver k3_ringacc_driver = {
> +	.probe		= k3_ringacc_probe,
> +	.remove		= k3_ringacc_remove,
> +	.driver		= {
> +		.name	= "k3-ringacc",
> +		.of_match_table = k3_ringacc_of_match,
> +	},
> +};
> +module_platform_driver(k3_ringacc_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("TI Ringacc driver for K3 SOCs");
> +MODULE_AUTHOR("Grygorii Strashko <grygorii.strashko@ti.com>");
> diff --git a/include/linux/soc/ti/k3-ringacc.h b/include/linux/soc/ti/k3-ringacc.h
> new file mode 100644
> index 000000000000..debffba48ac9
> --- /dev/null
> +++ b/include/linux/soc/ti/k3-ringacc.h
> @@ -0,0 +1,262 @@
> +/* 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
> + * @K3_RINGACC_RING_MODE_QM:  Queue manager mode. This takes the credentials
> + *	mode and adds packet length per element, along with additional read only
> + *	fields for element count and accumulated queue length. The QM mode only
> + *	operates with an 8 byte element size (any other element size is
> + *	illegal), and like in credentials mode each operation uses 2 element
> + *	slots to store the credentials and length fields
> + */
> +enum k3_ring_mode {
> +	K3_RINGACC_RING_MODE_RING = 0,
> +	K3_RINGACC_RING_MODE_MESSAGE,
> +	K3_RINGACC_RING_MODE_CREDENTIALS,
> +	K3_RINGACC_RING_MODE_QM,
> +	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).
> + * TODO_GS: ? Ring can be reused without reconfiguration
> + */
> +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);
> +
> +/**
> + * Debugging definitions
> + * TODO: might be removed
> + */
> +#ifdef CONFIG_TI_K3_RINGACC_DEBUG
> +void k3_ringacc_ring_dump(struct k3_ring *ring);
> +#else
> +static inline void k3_ringacc_ring_dump(struct k3_ring *ring) {};
> +#endif
> +
> +#endif /* __SOC_TI_K3_RINGACC_API_H_ */
> 

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