ARM: multi_v7_defconfig: enable CONFIG_UNIPHIER_MDMAC

[mirror_ubuntu-focal-kernel.git] / drivers / soc / qcom / qcom-geni-se.c

// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.

#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/qcom-geni-se.h>

/**
 * DOC: Overview
 *
 * Generic Interface (GENI) Serial Engine (SE) Wrapper driver is introduced
 * to manage GENI firmware based Qualcomm Universal Peripheral (QUP) Wrapper
 * controller. QUP Wrapper is designed to support various serial bus protocols
 * like UART, SPI, I2C, I3C, etc.
 */

/**
 * DOC: Hardware description
 *
 * GENI based QUP is a highly-flexible and programmable module for supporting
 * a wide range of serial interfaces like UART, SPI, I2C, I3C, etc. A single
 * QUP module can provide upto 8 serial interfaces, using its internal
 * serial engines. The actual configuration is determined by the target
 * platform configuration. The protocol supported by each interface is
 * determined by the firmware loaded to the serial engine. Each SE consists
 * of a DMA Engine and GENI sub modules which enable serial engines to
 * support FIFO and DMA modes of operation.
 *
 *
 *                      +-----------------------------------------+
 *                      |QUP Wrapper                              |
 *                      |         +----------------------------+  |
 *   --QUP & SE Clocks-->         | Serial Engine N            |  +-IO------>
 *                      |         | ...                        |  | Interface
 *   <---Clock Perf.----+    +----+-----------------------+    |  |
 *     State Interface  |    | Serial Engine 1            |    |  |
 *                      |    |                            |    |  |
 *                      |    |                            |    |  |
 *   <--------AHB------->    |                            |    |  |
 *                      |    |                            +----+  |
 *                      |    |                            |       |
 *                      |    |                            |       |
 *   <------SE IRQ------+    +----------------------------+       |
 *                      |                                         |
 *                      +-----------------------------------------+
 *
 *                         Figure 1: GENI based QUP Wrapper
 *
 * The GENI submodules include primary and secondary sequencers which are
 * used to drive TX & RX operations. On serial interfaces that operate using
 * master-slave model, primary sequencer drives both TX & RX operations. On
 * serial interfaces that operate using peer-to-peer model, primary sequencer
 * drives TX operation and secondary sequencer drives RX operation.
 */

/**
 * DOC: Software description
 *
 * GENI SE Wrapper driver is structured into 2 parts:
 *
 * geni_wrapper represents QUP Wrapper controller. This part of the driver
 * manages QUP Wrapper information such as hardware version, clock
 * performance table that is common to all the internal serial engines.
 *
 * geni_se represents serial engine. This part of the driver manages serial
 * engine information such as clocks, containing QUP Wrapper, etc. This part
 * of driver also supports operations (eg. initialize the concerned serial
 * engine, select between FIFO and DMA mode of operation etc.) that are
 * common to all the serial engines and are independent of serial interfaces.
 */

#define MAX_CLK_PERF_LEVEL 32
#define NUM_AHB_CLKS 2

/**
 * @struct geni_wrapper - Data structure to represent the QUP Wrapper Core
 * @dev:                Device pointer of the QUP wrapper core
 * @base:               Base address of this instance of QUP wrapper core
 * @ahb_clks:           Handle to the primary & secondary AHB clocks
 */
struct geni_wrapper {
        struct device *dev;
        void __iomem *base;
        struct clk_bulk_data ahb_clks[NUM_AHB_CLKS];
};

#define QUP_HW_VER_REG                  0x4

/* Common SE registers */
#define GENI_INIT_CFG_REVISION          0x0
#define GENI_S_INIT_CFG_REVISION        0x4
#define GENI_OUTPUT_CTRL                0x24
#define GENI_CGC_CTRL                   0x28
#define GENI_CLK_CTRL_RO                0x60
#define GENI_IF_DISABLE_RO              0x64
#define GENI_FW_S_REVISION_RO           0x6c
#define SE_GENI_BYTE_GRAN               0x254
#define SE_GENI_TX_PACKING_CFG0         0x260
#define SE_GENI_TX_PACKING_CFG1         0x264
#define SE_GENI_RX_PACKING_CFG0         0x284
#define SE_GENI_RX_PACKING_CFG1         0x288
#define SE_GENI_M_GP_LENGTH             0x910
#define SE_GENI_S_GP_LENGTH             0x914
#define SE_DMA_TX_PTR_L                 0xc30
#define SE_DMA_TX_PTR_H                 0xc34
#define SE_DMA_TX_ATTR                  0xc38
#define SE_DMA_TX_LEN                   0xc3c
#define SE_DMA_TX_IRQ_EN                0xc48
#define SE_DMA_TX_IRQ_EN_SET            0xc4c
#define SE_DMA_TX_IRQ_EN_CLR            0xc50
#define SE_DMA_TX_LEN_IN                0xc54
#define SE_DMA_TX_MAX_BURST             0xc5c
#define SE_DMA_RX_PTR_L                 0xd30
#define SE_DMA_RX_PTR_H                 0xd34
#define SE_DMA_RX_ATTR                  0xd38
#define SE_DMA_RX_LEN                   0xd3c
#define SE_DMA_RX_IRQ_EN                0xd48
#define SE_DMA_RX_IRQ_EN_SET            0xd4c
#define SE_DMA_RX_IRQ_EN_CLR            0xd50
#define SE_DMA_RX_LEN_IN                0xd54
#define SE_DMA_RX_MAX_BURST             0xd5c
#define SE_DMA_RX_FLUSH                 0xd60
#define SE_GSI_EVENT_EN                 0xe18
#define SE_IRQ_EN                       0xe1c
#define SE_DMA_GENERAL_CFG              0xe30

/* GENI_OUTPUT_CTRL fields */
#define DEFAULT_IO_OUTPUT_CTRL_MSK      GENMASK(6, 0)

/* GENI_CGC_CTRL fields */
#define CFG_AHB_CLK_CGC_ON              BIT(0)
#define CFG_AHB_WR_ACLK_CGC_ON          BIT(1)
#define DATA_AHB_CLK_CGC_ON             BIT(2)
#define SCLK_CGC_ON                     BIT(3)
#define TX_CLK_CGC_ON                   BIT(4)
#define RX_CLK_CGC_ON                   BIT(5)
#define EXT_CLK_CGC_ON                  BIT(6)
#define PROG_RAM_HCLK_OFF               BIT(8)
#define PROG_RAM_SCLK_OFF               BIT(9)
#define DEFAULT_CGC_EN                  GENMASK(6, 0)

/* SE_GSI_EVENT_EN fields */
#define DMA_RX_EVENT_EN                 BIT(0)
#define DMA_TX_EVENT_EN                 BIT(1)
#define GENI_M_EVENT_EN                 BIT(2)
#define GENI_S_EVENT_EN                 BIT(3)

/* SE_IRQ_EN fields */
#define DMA_RX_IRQ_EN                   BIT(0)
#define DMA_TX_IRQ_EN                   BIT(1)
#define GENI_M_IRQ_EN                   BIT(2)
#define GENI_S_IRQ_EN                   BIT(3)

/* SE_DMA_GENERAL_CFG */
#define DMA_RX_CLK_CGC_ON               BIT(0)
#define DMA_TX_CLK_CGC_ON               BIT(1)
#define DMA_AHB_SLV_CFG_ON              BIT(2)
#define AHB_SEC_SLV_CLK_CGC_ON          BIT(3)
#define DUMMY_RX_NON_BUFFERABLE         BIT(4)
#define RX_DMA_ZERO_PADDING_EN          BIT(5)
#define RX_DMA_IRQ_DELAY_MSK            GENMASK(8, 6)
#define RX_DMA_IRQ_DELAY_SHFT           6

/**
 * geni_se_get_qup_hw_version() - Read the QUP wrapper Hardware version
 * @se: Pointer to the corresponding serial engine.
 *
 * Return: Hardware Version of the wrapper.
 */
u32 geni_se_get_qup_hw_version(struct geni_se *se)
{
        struct geni_wrapper *wrapper = se->wrapper;

        return readl_relaxed(wrapper->base + QUP_HW_VER_REG);
}
EXPORT_SYMBOL(geni_se_get_qup_hw_version);

static void geni_se_io_set_mode(void __iomem *base)
{
        u32 val;

        val = readl_relaxed(base + SE_IRQ_EN);
        val |= GENI_M_IRQ_EN | GENI_S_IRQ_EN;
        val |= DMA_TX_IRQ_EN | DMA_RX_IRQ_EN;
        writel_relaxed(val, base + SE_IRQ_EN);

        val = readl_relaxed(base + SE_GENI_DMA_MODE_EN);
        val &= ~GENI_DMA_MODE_EN;
        writel_relaxed(val, base + SE_GENI_DMA_MODE_EN);

        writel_relaxed(0, base + SE_GSI_EVENT_EN);
}

static void geni_se_io_init(void __iomem *base)
{
        u32 val;

        val = readl_relaxed(base + GENI_CGC_CTRL);
        val |= DEFAULT_CGC_EN;
        writel_relaxed(val, base + GENI_CGC_CTRL);

        val = readl_relaxed(base + SE_DMA_GENERAL_CFG);
        val |= AHB_SEC_SLV_CLK_CGC_ON | DMA_AHB_SLV_CFG_ON;
        val |= DMA_TX_CLK_CGC_ON | DMA_RX_CLK_CGC_ON;
        writel_relaxed(val, base + SE_DMA_GENERAL_CFG);

        writel_relaxed(DEFAULT_IO_OUTPUT_CTRL_MSK, base + GENI_OUTPUT_CTRL);
        writel_relaxed(FORCE_DEFAULT, base + GENI_FORCE_DEFAULT_REG);
}

/**
 * geni_se_init() - Initialize the GENI serial engine
 * @se:         Pointer to the concerned serial engine.
 * @rx_wm:      Receive watermark, in units of FIFO words.
 * @rx_rfr_wm:  Ready-for-receive watermark, in units of FIFO words.
 *
 * This function is used to initialize the GENI serial engine, configure
 * receive watermark and ready-for-receive watermarks.
 */
void geni_se_init(struct geni_se *se, u32 rx_wm, u32 rx_rfr)
{
        u32 val;

        geni_se_io_init(se->base);
        geni_se_io_set_mode(se->base);

        writel_relaxed(rx_wm, se->base + SE_GENI_RX_WATERMARK_REG);
        writel_relaxed(rx_rfr, se->base + SE_GENI_RX_RFR_WATERMARK_REG);

        val = readl_relaxed(se->base + SE_GENI_M_IRQ_EN);
        val |= M_COMMON_GENI_M_IRQ_EN;
        writel_relaxed(val, se->base + SE_GENI_M_IRQ_EN);

        val = readl_relaxed(se->base + SE_GENI_S_IRQ_EN);
        val |= S_COMMON_GENI_S_IRQ_EN;
        writel_relaxed(val, se->base + SE_GENI_S_IRQ_EN);
}
EXPORT_SYMBOL(geni_se_init);

static void geni_se_select_fifo_mode(struct geni_se *se)
{
        u32 proto = geni_se_read_proto(se);
        u32 val;

        writel_relaxed(0, se->base + SE_GSI_EVENT_EN);
        writel_relaxed(0xffffffff, se->base + SE_GENI_M_IRQ_CLEAR);
        writel_relaxed(0xffffffff, se->base + SE_GENI_S_IRQ_CLEAR);
        writel_relaxed(0xffffffff, se->base + SE_DMA_TX_IRQ_CLR);
        writel_relaxed(0xffffffff, se->base + SE_DMA_RX_IRQ_CLR);
        writel_relaxed(0xffffffff, se->base + SE_IRQ_EN);

        val = readl_relaxed(se->base + SE_GENI_M_IRQ_EN);
        if (proto != GENI_SE_UART) {
                val |= M_CMD_DONE_EN | M_TX_FIFO_WATERMARK_EN;
                val |= M_RX_FIFO_WATERMARK_EN | M_RX_FIFO_LAST_EN;
        }
        writel_relaxed(val, se->base + SE_GENI_M_IRQ_EN);

        val = readl_relaxed(se->base + SE_GENI_S_IRQ_EN);
        if (proto != GENI_SE_UART)
                val |= S_CMD_DONE_EN;
        writel_relaxed(val, se->base + SE_GENI_S_IRQ_EN);

        val = readl_relaxed(se->base + SE_GENI_DMA_MODE_EN);
        val &= ~GENI_DMA_MODE_EN;
        writel_relaxed(val, se->base + SE_GENI_DMA_MODE_EN);
}

static void geni_se_select_dma_mode(struct geni_se *se)
{
        u32 val;

        writel_relaxed(0, se->base + SE_GSI_EVENT_EN);
        writel_relaxed(0xffffffff, se->base + SE_GENI_M_IRQ_CLEAR);
        writel_relaxed(0xffffffff, se->base + SE_GENI_S_IRQ_CLEAR);
        writel_relaxed(0xffffffff, se->base + SE_DMA_TX_IRQ_CLR);
        writel_relaxed(0xffffffff, se->base + SE_DMA_RX_IRQ_CLR);
        writel_relaxed(0xffffffff, se->base + SE_IRQ_EN);

        val = readl_relaxed(se->base + SE_GENI_DMA_MODE_EN);
        val |= GENI_DMA_MODE_EN;
        writel_relaxed(val, se->base + SE_GENI_DMA_MODE_EN);
}

/**
 * geni_se_select_mode() - Select the serial engine transfer mode
 * @se:         Pointer to the concerned serial engine.
 * @mode:       Transfer mode to be selected.
 */
void geni_se_select_mode(struct geni_se *se, enum geni_se_xfer_mode mode)
{
        WARN_ON(mode != GENI_SE_FIFO && mode != GENI_SE_DMA);

        switch (mode) {
        case GENI_SE_FIFO:
                geni_se_select_fifo_mode(se);
                break;
        case GENI_SE_DMA:
                geni_se_select_dma_mode(se);
                break;
        case GENI_SE_INVALID:
        default:
                break;
        }
}
EXPORT_SYMBOL(geni_se_select_mode);

/**
 * DOC: Overview
 *
 * GENI FIFO packing is highly configurable. TX/RX packing/unpacking consist
 * of up to 4 operations, each operation represented by 4 configuration vectors
 * of 10 bits programmed in GENI_TX_PACKING_CFG0 and GENI_TX_PACKING_CFG1 for
 * TX FIFO and in GENI_RX_PACKING_CFG0 and GENI_RX_PACKING_CFG1 for RX FIFO.
 * Refer to below examples for detailed bit-field description.
 *
 * Example 1: word_size = 7, packing_mode = 4 x 8, msb_to_lsb = 1
 *
 *        +-----------+-------+-------+-------+-------+
 *        |           | vec_0 | vec_1 | vec_2 | vec_3 |
 *        +-----------+-------+-------+-------+-------+
 *        | start     | 0x6   | 0xe   | 0x16  | 0x1e  |
 *        | direction | 1     | 1     | 1     | 1     |
 *        | length    | 6     | 6     | 6     | 6     |
 *        | stop      | 0     | 0     | 0     | 1     |
 *        +-----------+-------+-------+-------+-------+
 *
 * Example 2: word_size = 15, packing_mode = 2 x 16, msb_to_lsb = 0
 *
 *        +-----------+-------+-------+-------+-------+
 *        |           | vec_0 | vec_1 | vec_2 | vec_3 |
 *        +-----------+-------+-------+-------+-------+
 *        | start     | 0x0   | 0x8   | 0x10  | 0x18  |
 *        | direction | 0     | 0     | 0     | 0     |
 *        | length    | 7     | 6     | 7     | 6     |
 *        | stop      | 0     | 0     | 0     | 1     |
 *        +-----------+-------+-------+-------+-------+
 *
 * Example 3: word_size = 23, packing_mode = 1 x 32, msb_to_lsb = 1
 *
 *        +-----------+-------+-------+-------+-------+
 *        |           | vec_0 | vec_1 | vec_2 | vec_3 |
 *        +-----------+-------+-------+-------+-------+
 *        | start     | 0x16  | 0xe   | 0x6   | 0x0   |
 *        | direction | 1     | 1     | 1     | 1     |
 *        | length    | 7     | 7     | 6     | 0     |
 *        | stop      | 0     | 0     | 1     | 0     |
 *        +-----------+-------+-------+-------+-------+
 *
 */

#define NUM_PACKING_VECTORS 4
#define PACKING_START_SHIFT 5
#define PACKING_DIR_SHIFT 4
#define PACKING_LEN_SHIFT 1
#define PACKING_STOP_BIT BIT(0)
#define PACKING_VECTOR_SHIFT 10
/**
 * geni_se_config_packing() - Packing configuration of the serial engine
 * @se:         Pointer to the concerned serial engine
 * @bpw:        Bits of data per transfer word.
 * @pack_words: Number of words per fifo element.
 * @msb_to_lsb: Transfer from MSB to LSB or vice-versa.
 * @tx_cfg:     Flag to configure the TX Packing.
 * @rx_cfg:     Flag to configure the RX Packing.
 *
 * This function is used to configure the packing rules for the current
 * transfer.
 */
void geni_se_config_packing(struct geni_se *se, int bpw, int pack_words,
                            bool msb_to_lsb, bool tx_cfg, bool rx_cfg)
{
        u32 cfg0, cfg1, cfg[NUM_PACKING_VECTORS] = {0};
        int len;
        int temp_bpw = bpw;
        int idx_start = msb_to_lsb ? bpw - 1 : 0;
        int idx = idx_start;
        int idx_delta = msb_to_lsb ? -BITS_PER_BYTE : BITS_PER_BYTE;
        int ceil_bpw = ALIGN(bpw, BITS_PER_BYTE);
        int iter = (ceil_bpw * pack_words) / BITS_PER_BYTE;
        int i;

        if (iter <= 0 || iter > NUM_PACKING_VECTORS)
                return;

        for (i = 0; i < iter; i++) {
                len = min_t(int, temp_bpw, BITS_PER_BYTE) - 1;
                cfg[i] = idx << PACKING_START_SHIFT;
                cfg[i] |= msb_to_lsb << PACKING_DIR_SHIFT;
                cfg[i] |= len << PACKING_LEN_SHIFT;

                if (temp_bpw <= BITS_PER_BYTE) {
                        idx = ((i + 1) * BITS_PER_BYTE) + idx_start;
                        temp_bpw = bpw;
                } else {
                        idx = idx + idx_delta;
                        temp_bpw = temp_bpw - BITS_PER_BYTE;
                }
        }
        cfg[iter - 1] |= PACKING_STOP_BIT;
        cfg0 = cfg[0] | (cfg[1] << PACKING_VECTOR_SHIFT);
        cfg1 = cfg[2] | (cfg[3] << PACKING_VECTOR_SHIFT);

        if (tx_cfg) {
                writel_relaxed(cfg0, se->base + SE_GENI_TX_PACKING_CFG0);
                writel_relaxed(cfg1, se->base + SE_GENI_TX_PACKING_CFG1);
        }
        if (rx_cfg) {
                writel_relaxed(cfg0, se->base + SE_GENI_RX_PACKING_CFG0);
                writel_relaxed(cfg1, se->base + SE_GENI_RX_PACKING_CFG1);
        }

        /*
         * Number of protocol words in each FIFO entry
         * 0 - 4x8, four words in each entry, max word size of 8 bits
         * 1 - 2x16, two words in each entry, max word size of 16 bits
         * 2 - 1x32, one word in each entry, max word size of 32 bits
         * 3 - undefined
         */
        if (pack_words || bpw == 32)
                writel_relaxed(bpw / 16, se->base + SE_GENI_BYTE_GRAN);
}
EXPORT_SYMBOL(geni_se_config_packing);

static void geni_se_clks_off(struct geni_se *se)
{
        struct geni_wrapper *wrapper = se->wrapper;

        clk_disable_unprepare(se->clk);
        clk_bulk_disable_unprepare(ARRAY_SIZE(wrapper->ahb_clks),
                                                wrapper->ahb_clks);
}

/**
 * geni_se_resources_off() - Turn off resources associated with the serial
 *                           engine
 * @se: Pointer to the concerned serial engine.
 *
 * Return: 0 on success, standard Linux error codes on failure/error.
 */
int geni_se_resources_off(struct geni_se *se)
{
        int ret;

        ret = pinctrl_pm_select_sleep_state(se->dev);
        if (ret)
                return ret;

        geni_se_clks_off(se);
        return 0;
}
EXPORT_SYMBOL(geni_se_resources_off);

static int geni_se_clks_on(struct geni_se *se)
{
        int ret;
        struct geni_wrapper *wrapper = se->wrapper;

        ret = clk_bulk_prepare_enable(ARRAY_SIZE(wrapper->ahb_clks),
                                                wrapper->ahb_clks);
        if (ret)
                return ret;

        ret = clk_prepare_enable(se->clk);
        if (ret)
                clk_bulk_disable_unprepare(ARRAY_SIZE(wrapper->ahb_clks),
                                                        wrapper->ahb_clks);
        return ret;
}

/**
 * geni_se_resources_on() - Turn on resources associated with the serial
 *                          engine
 * @se: Pointer to the concerned serial engine.
 *
 * Return: 0 on success, standard Linux error codes on failure/error.
 */
int geni_se_resources_on(struct geni_se *se)
{
        int ret;

        ret = geni_se_clks_on(se);
        if (ret)
                return ret;

        ret = pinctrl_pm_select_default_state(se->dev);
        if (ret)
                geni_se_clks_off(se);

        return ret;
}
EXPORT_SYMBOL(geni_se_resources_on);

/**
 * geni_se_clk_tbl_get() - Get the clock table to program DFS
 * @se:         Pointer to the concerned serial engine.
 * @tbl:        Table in which the output is returned.
 *
 * This function is called by the protocol drivers to determine the different
 * clock frequencies supported by serial engine core clock. The protocol
 * drivers use the output to determine the clock frequency index to be
 * programmed into DFS.
 *
 * Return: number of valid performance levels in the table on success,
 *         standard Linux error codes on failure.
 */
int geni_se_clk_tbl_get(struct geni_se *se, unsigned long **tbl)
{
        long freq = 0;
        int i;

        if (se->clk_perf_tbl) {
                *tbl = se->clk_perf_tbl;
                return se->num_clk_levels;
        }

        se->clk_perf_tbl = devm_kcalloc(se->dev, MAX_CLK_PERF_LEVEL,
                                        sizeof(*se->clk_perf_tbl),
                                        GFP_KERNEL);
        if (!se->clk_perf_tbl)
                return -ENOMEM;

        for (i = 0; i < MAX_CLK_PERF_LEVEL; i++) {
                freq = clk_round_rate(se->clk, freq + 1);
                if (freq <= 0 || freq == se->clk_perf_tbl[i - 1])
                        break;
                se->clk_perf_tbl[i] = freq;
        }
        se->num_clk_levels = i;
        *tbl = se->clk_perf_tbl;
        return se->num_clk_levels;
}
EXPORT_SYMBOL(geni_se_clk_tbl_get);

/**
 * geni_se_clk_freq_match() - Get the matching or closest SE clock frequency
 * @se:         Pointer to the concerned serial engine.
 * @req_freq:   Requested clock frequency.
 * @index:      Index of the resultant frequency in the table.
 * @res_freq:   Resultant frequency of the source clock.
 * @exact:      Flag to indicate exact multiple requirement of the requested
 *              frequency.
 *
 * This function is called by the protocol drivers to determine the best match
 * of the requested frequency as provided by the serial engine clock in order
 * to meet the performance requirements.
 *
 * If we return success:
 * - if @exact is true  then @res_freq / <an_integer> == @req_freq
 * - if @exact is false then @res_freq / <an_integer> <= @req_freq
 *
 * Return: 0 on success, standard Linux error codes on failure.
 */
int geni_se_clk_freq_match(struct geni_se *se, unsigned long req_freq,
                           unsigned int *index, unsigned long *res_freq,
                           bool exact)
{
        unsigned long *tbl;
        int num_clk_levels;
        int i;
        unsigned long best_delta;
        unsigned long new_delta;
        unsigned int divider;

        num_clk_levels = geni_se_clk_tbl_get(se, &tbl);
        if (num_clk_levels < 0)
                return num_clk_levels;

        if (num_clk_levels == 0)
                return -EINVAL;

        best_delta = ULONG_MAX;
        for (i = 0; i < num_clk_levels; i++) {
                divider = DIV_ROUND_UP(tbl[i], req_freq);
                new_delta = req_freq - tbl[i] / divider;
                if (new_delta < best_delta) {
                        /* We have a new best! */
                        *index = i;
                        *res_freq = tbl[i];

                        /* If the new best is exact then we're done */
                        if (new_delta == 0)
                                return 0;

                        /* Record how close we got */
                        best_delta = new_delta;
                }
        }

        if (exact)
                return -EINVAL;

        return 0;
}
EXPORT_SYMBOL(geni_se_clk_freq_match);

#define GENI_SE_DMA_DONE_EN BIT(0)
#define GENI_SE_DMA_EOT_EN BIT(1)
#define GENI_SE_DMA_AHB_ERR_EN BIT(2)
#define GENI_SE_DMA_EOT_BUF BIT(0)
/**
 * geni_se_tx_dma_prep() - Prepare the serial engine for TX DMA transfer
 * @se:                 Pointer to the concerned serial engine.
 * @buf:                Pointer to the TX buffer.
 * @len:                Length of the TX buffer.
 * @iova:               Pointer to store the mapped DMA address.
 *
 * This function is used to prepare the buffers for DMA TX.
 *
 * Return: 0 on success, standard Linux error codes on failure.
 */
int geni_se_tx_dma_prep(struct geni_se *se, void *buf, size_t len,
                        dma_addr_t *iova)
{
        struct geni_wrapper *wrapper = se->wrapper;
        u32 val;

        *iova = dma_map_single(wrapper->dev, buf, len, DMA_TO_DEVICE);
        if (dma_mapping_error(wrapper->dev, *iova))
                return -EIO;

        val = GENI_SE_DMA_DONE_EN;
        val |= GENI_SE_DMA_EOT_EN;
        val |= GENI_SE_DMA_AHB_ERR_EN;
        writel_relaxed(val, se->base + SE_DMA_TX_IRQ_EN_SET);
        writel_relaxed(lower_32_bits(*iova), se->base + SE_DMA_TX_PTR_L);
        writel_relaxed(upper_32_bits(*iova), se->base + SE_DMA_TX_PTR_H);
        writel_relaxed(GENI_SE_DMA_EOT_BUF, se->base + SE_DMA_TX_ATTR);
        writel_relaxed(len, se->base + SE_DMA_TX_LEN);
        return 0;
}
EXPORT_SYMBOL(geni_se_tx_dma_prep);

/**
 * geni_se_rx_dma_prep() - Prepare the serial engine for RX DMA transfer
 * @se:                 Pointer to the concerned serial engine.
 * @buf:                Pointer to the RX buffer.
 * @len:                Length of the RX buffer.
 * @iova:               Pointer to store the mapped DMA address.
 *
 * This function is used to prepare the buffers for DMA RX.
 *
 * Return: 0 on success, standard Linux error codes on failure.
 */
int geni_se_rx_dma_prep(struct geni_se *se, void *buf, size_t len,
                        dma_addr_t *iova)
{
        struct geni_wrapper *wrapper = se->wrapper;
        u32 val;

        *iova = dma_map_single(wrapper->dev, buf, len, DMA_FROM_DEVICE);
        if (dma_mapping_error(wrapper->dev, *iova))
                return -EIO;

        val = GENI_SE_DMA_DONE_EN;
        val |= GENI_SE_DMA_EOT_EN;
        val |= GENI_SE_DMA_AHB_ERR_EN;
        writel_relaxed(val, se->base + SE_DMA_RX_IRQ_EN_SET);
        writel_relaxed(lower_32_bits(*iova), se->base + SE_DMA_RX_PTR_L);
        writel_relaxed(upper_32_bits(*iova), se->base + SE_DMA_RX_PTR_H);
        /* RX does not have EOT buffer type bit. So just reset RX_ATTR */
        writel_relaxed(0, se->base + SE_DMA_RX_ATTR);
        writel_relaxed(len, se->base + SE_DMA_RX_LEN);
        return 0;
}
EXPORT_SYMBOL(geni_se_rx_dma_prep);

/**
 * geni_se_tx_dma_unprep() - Unprepare the serial engine after TX DMA transfer
 * @se:                 Pointer to the concerned serial engine.
 * @iova:               DMA address of the TX buffer.
 * @len:                Length of the TX buffer.
 *
 * This function is used to unprepare the DMA buffers after DMA TX.
 */
void geni_se_tx_dma_unprep(struct geni_se *se, dma_addr_t iova, size_t len)
{
        struct geni_wrapper *wrapper = se->wrapper;

        if (iova && !dma_mapping_error(wrapper->dev, iova))
                dma_unmap_single(wrapper->dev, iova, len, DMA_TO_DEVICE);
}
EXPORT_SYMBOL(geni_se_tx_dma_unprep);

/**
 * geni_se_rx_dma_unprep() - Unprepare the serial engine after RX DMA transfer
 * @se:                 Pointer to the concerned serial engine.
 * @iova:               DMA address of the RX buffer.
 * @len:                Length of the RX buffer.
 *
 * This function is used to unprepare the DMA buffers after DMA RX.
 */
void geni_se_rx_dma_unprep(struct geni_se *se, dma_addr_t iova, size_t len)
{
        struct geni_wrapper *wrapper = se->wrapper;

        if (iova && !dma_mapping_error(wrapper->dev, iova))
                dma_unmap_single(wrapper->dev, iova, len, DMA_FROM_DEVICE);
}
EXPORT_SYMBOL(geni_se_rx_dma_unprep);

static int geni_se_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct resource *res;
        struct geni_wrapper *wrapper;
        int ret;

        wrapper = devm_kzalloc(dev, sizeof(*wrapper), GFP_KERNEL);
        if (!wrapper)
                return -ENOMEM;

        wrapper->dev = dev;
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        wrapper->base = devm_ioremap_resource(dev, res);
        if (IS_ERR(wrapper->base))
                return PTR_ERR(wrapper->base);

        wrapper->ahb_clks[0].id = "m-ahb";
        wrapper->ahb_clks[1].id = "s-ahb";
        ret = devm_clk_bulk_get(dev, NUM_AHB_CLKS, wrapper->ahb_clks);
        if (ret) {
                dev_err(dev, "Err getting AHB clks %d\n", ret);
                return ret;
        }

        dev_set_drvdata(dev, wrapper);
        dev_dbg(dev, "GENI SE Driver probed\n");
        return devm_of_platform_populate(dev);
}

static const struct of_device_id geni_se_dt_match[] = {
        { .compatible = "qcom,geni-se-qup", },
        {}
};
MODULE_DEVICE_TABLE(of, geni_se_dt_match);

static struct platform_driver geni_se_driver = {
        .driver = {
                .name = "geni_se_qup",
                .of_match_table = geni_se_dt_match,
        },
        .probe = geni_se_probe,
};
module_platform_driver(geni_se_driver);

MODULE_DESCRIPTION("GENI Serial Engine Driver");
MODULE_LICENSE("GPL v2");