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Message-ID: <8866de0e7a687cea1d800d6b3dcfb60b@codeaurora.org>
Date: Wed, 26 Sep 2018 01:06:30 +0530
From: dkota@...eaurora.org
To: Stephen Boyd <swboyd@...omium.org>
Cc: broonie@...nel.org, dianders@...omium.org,
linux-kernel@...r.kernel.org, linux-spi@...r.kernel.org,
mka@...omium.org, linux-arm-msm@...r.kernel.org,
Girish Mahadevan <girishm@...eaurora.org>
Subject: Re: [PATCH V4 3/4] spi: spi-geni-qcom: Add SPI driver support for
GENI based QUP
[...]
>> +#define TIMESTAMP_BEFORE BIT(1)
>> +#define FRAGMENTATION BIT(2)
>> +#define TIMESTAMP_AFTER BIT(3)
>> +#define POST_CMD_DELAY BIT(4)
>> +
>> +static irqreturn_t geni_spi_isr(int irq, void *data);
>
> Does this need to be forward declared?
Not required, will remove it.
>
>> +
>> +struct spi_geni_master {
>> + struct geni_se se;
>> + struct device *dev;
>> + u32 rx_fifo_depth;
>
> Is this used?
It can be removed.
>
>> + u32 tx_fifo_depth;
>> + u32 fifo_width_bits;
>> + u32 tx_wm;
>> + unsigned int cur_speed_hz;
>
> unsigned long for Hz? The clk framework uses that type.
cur_speed_hz stores the speed value requested as part of transfer (not
the resultant or rounded off frequency got from clk framework. It is u32
type, i will change cur_speed_hz to u32 type instead of unsigned long.
Code snippet:
mas->cur_speed_hz = xfer->speed_hz;
>
>> + unsigned int cur_bits_per_word;
>> + unsigned int tx_rem_bytes;
>> + unsigned int rx_rem_bytes;
>> + struct spi_transfer *cur_xfer;
>
> const?
Yes can be marked as const, will update it.
>
>> + struct completion xfer_done;
>> + unsigned int oversampling;
>> + spinlock_t lock;
>> +};
>> +
> [...]
>> +
>> +static int spi_geni_prepare_message(struct spi_master *spi,
>> + struct spi_message *spi_msg)
>> +{
>> + int ret;
>> + struct spi_geni_master *mas = spi_master_get_devdata(spi);
>> + struct geni_se *se = &mas->se;
>> +
>> + geni_se_select_mode(se, GENI_SE_FIFO);
>> + reinit_completion(&mas->xfer_done);
>> + ret = setup_fifo_params(spi_msg->spi, spi);
>> + if (ret)
>> + dev_err(mas->dev, "Couldn't select mode %d", ret);
>
> Missing newline on error print.
>
Will add it.
>> + return ret;
>> +}
>> +
> [...]
>> +
>> +static void setup_fifo_xfer(struct spi_transfer *xfer,
>> + struct spi_geni_master *mas,
>> + u16 mode, struct spi_master *spi)
>> +{
>> + u32 m_cmd = 0, m_param = 0;
>> + u32 spi_tx_cfg, trans_len;
>> + struct geni_se *se = &mas->se;
>> +
>> + spi_tx_cfg = readl(se->base + SE_SPI_TRANS_CFG);
>> + if (xfer->bits_per_word != mas->cur_bits_per_word) {
>> + spi_setup_word_len(mas, mode, xfer->bits_per_word);
>> + mas->cur_bits_per_word = xfer->bits_per_word;
>> + }
>> +
>> + /* Speed and bits per word can be overridden per transfer */
>> + if (xfer->speed_hz != mas->cur_speed_hz) {
>> + int ret;
>> + u32 clk_sel, m_clk_cfg;
>> + unsigned int idx, div;
>> +
>> + ret = get_spi_clk_cfg(xfer->speed_hz, mas, &idx,
>> &div);
>> + if (ret) {
>> + dev_err(mas->dev, "Err setting clks:%d\n",
>> ret);
>> + return;
>> + }
>> + /*
>> + * SPI core clock gets configured with the requested
>> frequency
>> + * or the frequency closer to the requested frequency.
>> + * For that reason requested frequency is stored in
>> the
>> + * cur_speed_hz and referred in the consicutive
>> transfer instead
>
> s/consicutive/consecutive/
will correct it.
>
>> + * of calling clk_get_rate() API.
>> + */
>> + mas->cur_speed_hz = xfer->speed_hz;
>> + clk_sel = idx & CLK_SEL_MSK;
>> + m_clk_cfg = (div << CLK_DIV_SHFT) | SER_CLK_EN;
>> + writel(clk_sel, se->base + SE_GENI_CLK_SEL);
>> + writel(m_clk_cfg, se->base + GENI_SER_M_CLK_CFG);
>> + }
>> +
>> + mas->tx_rem_bytes = 0;
>> + mas->rx_rem_bytes = 0;
>> + if (xfer->tx_buf && xfer->rx_buf)
>> + m_cmd = SPI_FULL_DUPLEX;
>> + else if (xfer->tx_buf)
>> + m_cmd = SPI_TX_ONLY;
>> + else if (xfer->rx_buf)
>> + m_cmd = SPI_RX_ONLY;
>> +
>> + spi_tx_cfg &= ~CS_TOGGLE;
>> + if (!(mas->cur_bits_per_word % MIN_WORD_LEN)) {
>> + trans_len =
>> + (xfer->len * BITS_PER_BYTE /
>> + mas->cur_bits_per_word) &
>> TRANS_LEN_MSK;
>> + } else {
>> + unsigned int bytes_per_word =
>> + mas->cur_bits_per_word / BITS_PER_BYTE + 1;
>> +
>> + trans_len = (xfer->len / bytes_per_word) &
>> TRANS_LEN_MSK;
>> + }
>
> Rename 'trans_len' to 'len' and shorten some lines by taking out the
> mask to get:
>
> if (!(mas->cur_bits_per_word % MIN_WORD_LEN))
> len = xfer->len * BITS_PER_BYTE / mas->cur_bits_per_word
> else
> len = xfer->len / (mas->cur_bits_per_word /
> BITS_PER_BYTE + 1);
> len &= TRANS_LEN_MSK;
>
OK
>> +
>> + /*
>> + * If CS change flag is set, then toggle the CS line in
>> between
>> + * transfers and keep CS asserted after the last transfer.
>> + * Else if keep CS flag asserted in between transfers and
>> de-assert
>> + * CS after the last message.
>> + */
>> + if (xfer->cs_change) {
>> + if (list_is_last(&xfer->transfer_list,
>> + &spi->cur_msg->transfers))
>> + m_param = FRAGMENTATION;
>> + } else {
>> + if (!list_is_last(&xfer->transfer_list,
>> + &spi->cur_msg->transfers))
>> + m_param = FRAGMENTATION;
>> + }
>> +
>> + mas->cur_xfer = xfer;
>> + if (m_cmd & SPI_TX_ONLY) {
>> + mas->tx_rem_bytes = xfer->len;
>> + writel(trans_len, se->base + SE_SPI_TX_TRANS_LEN);
>> + }
>> +
>> + if (m_cmd & SPI_RX_ONLY) {
>> + writel(trans_len, se->base + SE_SPI_RX_TRANS_LEN);
>> + mas->rx_rem_bytes = xfer->len;
>> + }
>> + writel(spi_tx_cfg, se->base + SE_SPI_TRANS_CFG);
>> + geni_se_setup_m_cmd(se, m_cmd, m_param);
>> +
>> + /*
>> + * TX_WATERMARK_REG should be set after SPI configuration and
>> + * setting up GENI SE engine, as driver starts data transfer
>> + * for the watermark interrupt.
>> + */
>> + if (m_cmd & SPI_TX_ONLY)
>> + writel(mas->tx_wm, se->base +
>> SE_GENI_TX_WATERMARK_REG);
>> +}
>> +
>> +static void handle_fifo_timeout(struct spi_master *spi,
>> + struct spi_message *msg)
>> +{
>> + struct spi_geni_master *mas = spi_master_get_devdata(spi);
>> + unsigned long timeout, flags;
>> + struct geni_se *se = &mas->se;
>> +
>> + spin_lock_irqsave(&mas->lock, flags);
>> + reinit_completion(&mas->xfer_done);
>> + geni_se_cancel_m_cmd(se);
>> + writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
>> + spin_unlock_irqrestore(&mas->lock, flags);
>> + timeout = wait_for_completion_timeout(&mas->xfer_done, HZ);
>
> Can you rename this time_left or completed? Then the if condition reads
> properly as "if not time left" or "if not completed". And then invert
> that logic so things aren't so indented?
>
> time_left = wait_for_completion_timeout(..)
> if (time_left)
> return;
>
> spin_lock_irqsave(&mas->lock, flags);
> reinit_completion(..)
> ...
>
Ok
>> + if (!timeout) {
>> + spin_lock_irqsave(&mas->lock, flags);
>> + reinit_completion(&mas->xfer_done);
>> + geni_se_abort_m_cmd(se);
>> + spin_unlock_irqrestore(&mas->lock, flags);
>> + timeout = wait_for_completion_timeout(&mas->xfer_done,
>> + HZ);
>> + if (!timeout)
>> + dev_err(mas->dev,
>> + "Failed to cancel/abort m_cmd\n");
>> + }
>> +}
>> +
>> +static int spi_geni_transfer_one(struct spi_master *spi,
>> + struct spi_device *slv,
>> + struct spi_transfer *xfer)
>> +{
>> + struct spi_geni_master *mas = spi_master_get_devdata(spi);
>> +
>> + setup_fifo_xfer(xfer, mas, slv->mode, spi);
>> + return 1;
>> +}
>> +
>> +static unsigned int geni_byte_per_fifo_word(struct spi_geni_master
>> *mas)
>> +{
>> + /*
>> + * Calculate how many bytes we'll put in each FIFO word. If
>> the
>> + * transfer words don't pack cleanly into a FIFO word we'll
>> just put
>> + * one transfer word in each FIFO word. If they do pack we'll
>> pack 'em.
>> + */
>> + if (mas->fifo_width_bits % mas->cur_bits_per_word)
>> + return
>> roundup_pow_of_two(DIV_ROUND_UP(mas->cur_bits_per_word,
>> +
>> BITS_PER_BYTE));
>> + else
>> + return mas->fifo_width_bits / BITS_PER_BYTE;
>
> Just do a return. No else please.
>
Ok
>> +}
>> +
>> +static irqreturn_t geni_spi_handle_tx(struct spi_geni_master *mas)
>> +{
>> + struct geni_se *se = &mas->se;
>> + unsigned int max_bytes;
>> + const u8 *tx_buf;
>> + unsigned int bytes_per_fifo_word =
>> geni_byte_per_fifo_word(mas);
>> + unsigned int i = 0;
>> +
>> + if (!mas->cur_xfer)
>> + return IRQ_NONE;
>> +
>> + max_bytes = (mas->tx_fifo_depth - mas->tx_wm) *
>> bytes_per_fifo_word;
>> + if (mas->tx_rem_bytes < max_bytes)
>> + max_bytes = mas->tx_rem_bytes;
>> +
>> + tx_buf = mas->cur_xfer->tx_buf + mas->cur_xfer->len -
>> mas->tx_rem_bytes;
>> + while (i < max_bytes) {
>> + unsigned int j;
>> + unsigned int bytes_to_write;
>> + u32 fifo_word = 0;
>> + u8 *fifo_byte = (u8 *)&fifo_word;
>> +
>> + bytes_to_write = min(bytes_per_fifo_word, max_bytes -
>> i);
>> + for (j = 0; j < bytes_to_write; j++)
>> + fifo_byte[j] = tx_buf[i++];
>> + iowrite32_rep(se->base + SE_GENI_TX_FIFOn, &fifo_word,
>> 1);
>> + }
>> + mas->tx_rem_bytes -= max_bytes;
>> + if (!mas->tx_rem_bytes)
>> + writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static irqreturn_t geni_spi_handle_rx(struct spi_geni_master *mas)
>> +{
>> + struct geni_se *se = &mas->se;
>> + u32 rx_fifo_status;
>> + unsigned int rx_bytes;
>> + u8 *rx_buf;
>> + unsigned int bytes_per_fifo_word =
>> geni_byte_per_fifo_word(mas);
>> + unsigned int i = 0;
>> +
>> + if (!mas->cur_xfer)
>> + return IRQ_NONE;
>> +
>> + rx_fifo_status = readl(se->base + SE_GENI_RX_FIFO_STATUS);
>
> Rename to 'status'? rx_fifo is implicit in the register macro.
Declared as "rx_fifo_status" for code readability.
>
>> + rx_bytes = (rx_fifo_status & RX_FIFO_WC_MSK) *
>> bytes_per_fifo_word;
>> + if (rx_fifo_status & RX_LAST) {
>> + unsigned int rx_last_byte_valid =
>> + (rx_fifo_status & RX_LAST_BYTE_VALID_MSK)
>> + >> RX_LAST_BYTE_VALID_SHFT;
>
> Hoist this variable into function scope? So then the line is:
>
> last_valid = status & RX_LAST_BYTE_VALID_MSK;
> last_valid >>= RX_LAST_BYTE_VALID_SHFT;
>
Ok
>> + if (rx_last_byte_valid && (rx_last_byte_valid < 4))
>
> Drop useless parenthesis please.
>
Ok
>> + rx_bytes -= bytes_per_fifo_word -
>> rx_last_byte_valid;
>> + }
>> + if (mas->rx_rem_bytes < rx_bytes)
>> + rx_bytes = mas->rx_rem_bytes;
>> +
>> + rx_buf = mas->cur_xfer->rx_buf + mas->cur_xfer->len -
>> mas->rx_rem_bytes;
>> + while (i < rx_bytes) {
>> + u32 fifo_word = 0;
>> + u8 *fifo_byte = (u8 *)&fifo_word;
>> + unsigned int bytes_to_read;
>> + unsigned int j;
>> +
>> + bytes_to_read = min(bytes_per_fifo_word, rx_bytes -
>> i);
>> + ioread32_rep(se->base + SE_GENI_RX_FIFOn, &fifo_word,
>> 1);
>> + for (j = 0; j < bytes_to_read; j++)
>> + rx_buf[i++] = fifo_byte[j];
>> + }
>> + mas->rx_rem_bytes -= rx_bytes;
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static irqreturn_t geni_spi_isr(int irq, void *data)
>> +{
>> + struct spi_master *spi = data;
>> + struct spi_geni_master *mas = spi_master_get_devdata(spi);
>> + struct geni_se *se = &mas->se;
>> + u32 m_irq;
>> + unsigned long flags;
>> + irqreturn_t ret = IRQ_HANDLED;
>> +
>> + if (pm_runtime_status_suspended(mas->dev))
>> + return IRQ_NONE;
>> +
>> + spin_lock_irqsave(&mas->lock, flags);
>> + m_irq = readl(se->base + SE_GENI_M_IRQ_STATUS);
>> + if ((m_irq & M_RX_FIFO_WATERMARK_EN) || (m_irq &
>> M_RX_FIFO_LAST_EN))
>> + ret = geni_spi_handle_rx(mas);
>> +
>> + if (m_irq & M_TX_FIFO_WATERMARK_EN)
>> + ret = geni_spi_handle_tx(mas);
>
> Is it possible for all three conditions above to happen in one
> interrupt? I ask because 'ret' is overwritten and so what may have been
> IRQ_HANDLED may become IRQ_NONE which will lead to confusion in the irq
> layer. Maybe the handle tx/rx functions can return a bool, that gets
> orred together each time so that we know if something handled an
> interrupt?
>
Will check it again by running fullduplex transfer and update.
>> +
>> + if (m_irq & M_CMD_DONE_EN) {
>> + spi_finalize_current_transfer(spi);
>> + /*
>> + * If this happens, then a CMD_DONE came before all
>> the Tx
>> + * buffer bytes were sent out. This is unusual, log
>> this
>> + * condition and disable the WM interrupt to prevent
>> the
>> + * system from stalling due an interrupt storm.
>> + * If this happens when all Rx bytes haven't been
>> received, log
>> + * the condition.
>> + * The only known time this can happen is if
>> bits_per_word != 8
>> + * and some registers that expect xfer lengths in num
>> spi_words
>> + * weren't written correctly.
>> + */
>> + if (mas->tx_rem_bytes) {
>> + writel(0, se->base +
>> SE_GENI_TX_WATERMARK_REG);
>> + dev_err(mas->dev, "Premature Done.tx_rem%d
>> bpw%d\n",
>
> Why isn't there a space after "Done."? And why is 'done' capitalized?
> Should 'tx_rem' be 'tx_rem='?
Yes, will update.
>
>> + mas->tx_rem_bytes,
>> mas->cur_bits_per_word);
>> + }
>> + if (mas->rx_rem_bytes)
>> + dev_err(mas->dev, "Premature Done.rx_rem%d
>> bpw%d\n",
>> + mas->rx_rem_bytes,
>> mas->cur_bits_per_word);
>> + }
>> +
>> + if ((m_irq & M_CMD_CANCEL_EN) || (m_irq & M_CMD_ABORT_EN))
>> + complete(&mas->xfer_done);
>> +
>> + writel(m_irq, se->base + SE_GENI_M_IRQ_CLEAR);
>> + spin_unlock_irqrestore(&mas->lock, flags);
>> + return ret;
>> +}
>> +
>> +static int spi_geni_probe(struct platform_device *pdev)
>> +{
>> + int ret;
>> + struct spi_master *spi;
>> + struct spi_geni_master *mas;
>> + struct resource *res;
>> + struct geni_se *se;
>> +
>> + spi = spi_alloc_master(&pdev->dev, sizeof(struct
>> spi_geni_master));
>
> sizeof(*mas) for code clarity?
>
Ok
>> + if (!spi)
>> + return -ENOMEM;
>> +
>> + platform_set_drvdata(pdev, spi);
>> + mas = spi_master_get_devdata(spi);
>> + mas->dev = &pdev->dev;
>> + mas->se.dev = &pdev->dev;
>> + mas->se.wrapper = dev_get_drvdata(pdev->dev.parent);
>> + se = &mas->se;
>> +
>> + spi->bus_num = -1;
>> + spi->dev.of_node = pdev->dev.of_node;
>> + mas->se.clk = devm_clk_get(&pdev->dev, "se");
>> + if (IS_ERR(mas->se.clk)) {
>> + ret = PTR_ERR(mas->se.clk);
>> + dev_err(&pdev->dev, "Err getting SE Core clk %d\n",
>> ret);
>> + goto spi_geni_probe_err;
>> + }
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + se->base = devm_ioremap_resource(&pdev->dev, res);
>> + if (IS_ERR(se->base)) {
>> + ret = -ENOMEM;
>
> ret = PTR_ERR(se->base);
>
> so we don't lose the error value.
>
Ok
>> + goto spi_geni_probe_err;
>> + }
>> +
>> + ret = platform_get_irq(pdev, 0);
>> + if (ret < 0) {
>> + dev_err(&pdev->dev, "Err getting IRQ %d\n", ret);
>> + goto spi_geni_probe_err;
>> + }
>> + ret = devm_request_irq(&pdev->dev, ret, geni_spi_isr,
>> + IRQF_TRIGGER_HIGH, "spi_geni", spi);
>> + if (ret)
>> + goto spi_geni_probe_err;
>
> Can you request this irq as late as possible in the probe function? I
> worry there may be some pending irq line set and then this will cause
> an
> interrupt storm with IRQ_NONE returned because the device is runtime
> suspended.
>
Ok; will call it after spi_register_master()
>> +
>> + spi->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP | SPI_CS_HIGH;
>> + spi->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
>> + spi->num_chipselect = 4;
>> + spi->max_speed_hz = 50000000;
>> + spi->prepare_message = spi_geni_prepare_message;
>> + spi->transfer_one = spi_geni_transfer_one;
>> + spi->auto_runtime_pm = true;
>> + spi->handle_err = handle_fifo_timeout;
>> +
>> + init_completion(&mas->xfer_done);
>> + spin_lock_init(&mas->lock);
>> + pm_runtime_enable(&pdev->dev);
>> +
>> + ret = spi_geni_init(mas);
>> + if (ret)
>> + goto spi_geni_probe_runtime_disable;
>> +
>> + ret = spi_register_master(spi);
>> + if (ret)
>> + goto spi_geni_probe_runtime_disable;
>> +
>> + return 0;
>> +spi_geni_probe_runtime_disable:
>> + pm_runtime_disable(&pdev->dev);
>> +spi_geni_probe_err:
>> + spi_master_put(spi);
>> + return ret;
>> +}
>> +
>> +static int spi_geni_remove(struct platform_device *pdev)
>> +{
>> + struct spi_master *spi = platform_get_drvdata(pdev);
>> +
>> + /* Unregister _before_ disabling pm_runtime() so we stop
>> transfers */
>> + spi_unregister_master(spi);
>> +
>> + pm_runtime_disable(&pdev->dev);
>> + return 0;
>> +}
>> +
>> +static int __maybe_unused spi_geni_runtime_suspend(struct device
>> *dev)
>> +{
>> + struct spi_master *spi = dev_get_drvdata(dev);
>> + struct spi_geni_master *mas = spi_master_get_devdata(spi);
>> +
>> + return geni_se_resources_off(&mas->se);
>> +}
>> +
>> +static int __maybe_unused spi_geni_runtime_resume(struct device *dev)
>> +{
>> + struct spi_master *spi = dev_get_drvdata(dev);
>> + struct spi_geni_master *mas = spi_master_get_devdata(spi);
>> +
>> + return geni_se_resources_on(&mas->se);
>> +}
>> +
>> +static int __maybe_unused spi_geni_suspend(struct device *dev)
>> +{
>> + if (!pm_runtime_status_suspended(dev))
>> + return -EBUSY;
>> + return 0;
>> +}
>> +
>> +static const struct dev_pm_ops spi_geni_pm_ops = {
>> + SET_RUNTIME_PM_OPS(spi_geni_runtime_suspend,
>> + spi_geni_runtime_resume, NULL)
>> + SET_SYSTEM_SLEEP_PM_OPS(spi_geni_suspend, NULL)
>> +};
>> +
>> +static const struct of_device_id spi_geni_dt_match[] = {
>> + { .compatible = "qcom,geni-spi" },
>> + {}
>> +};
>
> Please add a MODULE_DEVICE_TABLE(of, spi_geni_dt_match) here.
>
Ok
>> +
>> +static struct platform_driver spi_geni_driver = {
>> + .probe = spi_geni_probe,
>> + .remove = spi_geni_remove,
>> + .driver = {
>> + .name = "geni_spi",
>> + .pm = &spi_geni_pm_ops,
>> + .of_match_table = spi_geni_dt_match,
>> + },
>> +};
>> +module_platform_driver(spi_geni_driver);
>> +
>> +MODULE_DESCRIPTION("SPI driver for GENI based QUP cores");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/include/linux/spi/spi-geni-qcom.h
>> b/include/linux/spi/spi-geni-qcom.h
>> new file mode 100644
>> index 0000000..dc95764
>> --- /dev/null
>> +++ b/include/linux/spi/spi-geni-qcom.h
>> @@ -0,0 +1,14 @@
>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
>> +/*
>> + * Copyright (c) 2017-2018, The Linux Foundation. All rights
>> reserved.
>> + */
>> +
>> +#ifndef __SPI_GENI_QCOM_HEADER___
>> +#define __SPI_GENI_QCOM_HEADER___
>> +
>> +struct spi_geni_qcom_ctrl_data {
>> + u32 spi_cs_clk_delay;
>> + u32 spi_inter_words_delay;
>
> It was decided we still needed this? I don't see it in v3 so please
> remove this file unless it's needed.
Its not required; I will remove it.
Along with these changes, i will submit the fixes of loopback issue and
suspend/resume issue.
--Dilip
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