RE: [PATCH linux-next v6 1/1] spi: imx: Add support for SPI Slave mode

From: Palacios, Hector
Date: Tue Sep 05 2017 - 10:29:09 EST

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In reply to: Fabio Estevam: "Re: [PATCH linux-next v6 1/1] spi: imx: Add support for SPI Slave mode"
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Hi,

On Tue, 5 Sep 2017 16:15, Fabio Estevam wrote:
> [Adding Hector on Cc in case he could send his Tested-by tag]

I backported and tested this on a v4.1 so I'm not sure it qualifies for a Tested-by. :-(

> On Tue, Sep 5, 2017 at 2:12 AM, Jiada Wang <jiada_wang@xxxxxxxxxx> wrote:
>> Previously i.MX SPI controller only works in Master mode.
>> This patch adds support to i.MX51, i.MX53 and i.MX6 ECSPI
>> controller to work also in Slave mode.
>>
>> Currently SPI Slave mode support patch has the following limitations:
>> 1. The stale data in RXFIFO will be dropped when the Slave does any new
>> transfer. 2. One transfer can be finished only after all transfer->len data been transferred
>> to master device
>> 3. Slave device only accepts transfer->len data. Any data longer than
> this
>> from master device will be dropped. Any data shorter than this from
>> master will cause SPI to stuck due to mentioned HW limitation 2.
>> 4. Only PIO transfer is supported in Slave mode.
>> 5. Dynamic burst size adjust isn't supported in Slave mode.
>>
>> Following HW limitation applies:
>> 1. ECSPI has a HW issue when works in Slave mode, after 64
>> words written to TXFIFO, even TXFIFO becomes empty, ECSPI_TXDATA keeps shift out the last
>> word data, so we have to disable ECSPI when in slave mode after the transfer completes 2.
>> Due to Freescale errata ERR003775 "eCSPI: Burst completion by Chip Select (SS) signal in
>> Slave mode is not functional" burst size must be set exactly to the size of the transfer.
>> This limit SPI transaction with maximum 2^12 bits. This errata affects i.MX53 and i.MX6
>> ECSPI controllers.
>> Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
>> ---
>> Changes in v6:
>> * rebased to HEAD of linux-next tree
>> * avoid to enable dynamic burst adjust when in slave mode.
>>
>> Changes in v5:
>> * rebased to HEAD of linux-next tree
>>
>> Changes in v4:
>> * rebased to head of linux-next to resolve conflict
>> * optimized mx53_ecspi_rx_slave()
>>
>> Changes in v3:
>> * renamed several variables for for better readability
>> * created spi_imx_pio_transfer_slave() for slave pio transfer
>> * added fifo_size, has_dmamode and has_slavemode in spi_imx_devtype_data
>>
>> Changes in v2:
>> * re-workd i.MX ECSPI controller slave mode support based on Geert's work
>>
>> drivers/spi/spi-imx.c | 227 +++++++++++++++++++++++++++++++++++++++++++- ------ 1 file changed,
>> 196 insertions(+), 31 deletions(-)
>> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
>> index 6fcb6ad..401951c 100644
>> --- a/drivers/spi/spi-imx.c
>> +++ b/drivers/spi/spi-imx.c
>> @@ -53,10 +53,13 @@
>> /* generic defines to abstract from the different register layouts */
>> #define MXC_INT_RR (1 << 0) /* Receive data ready interrupt */
>> #define MXC_INT_TE (1 << 1) /* Transmit FIFO empty interrupt */
>> +#define MXC_INT_RDR BIT(4) /* Receive date threshold interrupt */
>>
>> /* The maximum bytes that a sdma BD can transfer.*/
>> #define MAX_SDMA_BD_BYTES (1 << 15)
>> #define MX51_ECSPI_CTRL_MAX_BURST 512
>> +/* The maximum bytes that IMX53_ECSPI can transfer in slave mode.*/
>> +#define MX53_MAX_TRANSFER_BYTES 512
>>
>> enum spi_imx_devtype {
>> IMX1_CSPI, @@ -76,7 +79,9 @@ struct spi_imx_devtype_data { void (*trigger)(struct
>> spi_imx_data *); int (*rx_available)(struct spi_imx_data *); void (*reset)(struct
>> spi_imx_data *); + void (*disable)(struct spi_imx_data *); bool has_dmamode; +
>> bool has_slavemode; unsigned int fifo_size; bool dynamic_burst; enum spi_imx_devtype
>> devtype; @@ -108,6 +113,11 @@ struct spi_imx_data { unsigned int dynamic_burst,
>> read_u32; unsigned int word_mask;
>> + /* Slave mode */
>> + bool slave_mode;
>> + bool slave_aborted;
>> + unsigned int slave_burst;
>> +
>> /* DMA */
>> bool usedma;
>> u32 wml;
>> @@ -221,6 +231,9 @@ static bool spi_imx_can_dma(struct spi_master
> *master, struct spi_device *spi,
>> if (!master->dma_rx)
>> return false;
>> + if (spi_imx->slave_mode)
>> + return false;
>> +
>> bytes_per_word = spi_imx_bytes_per_word(transfer->bits_per_word);
>>
>> if (bytes_per_word != 1 && bytes_per_word != 2 && bytes_per_word
> != 4)
>> @@ -262,6 +275,7 @@ static bool spi_imx_can_dma(struct spi_master
> *master, struct spi_device *spi,
>> #define MX51_ECSPI_INT 0x10
>> #define MX51_ECSPI_INT_TEEN (1 << 0)
>> #define MX51_ECSPI_INT_RREN (1 << 3)
>> +#define MX51_ECSPI_INT_RDREN (1 << 4)
>>
>> #define MX51_ECSPI_DMA 0x14
>> #define MX51_ECSPI_DMA_TX_WML(wml) ((wml) & 0x3f)
>> @@ -378,6 +392,44 @@ static void spi_imx_buf_tx_swap(struct spi_imx_data
> *spi_imx)
>> spi_imx_buf_tx_u16(spi_imx);
>> }
>> +static void mx53_ecspi_rx_slave(struct spi_imx_data *spi_imx)
>> +{
>> + u32 val = be32_to_cpu(readl(spi_imx->base + MXC_CSPIRXDATA));
>> +
>> + if (spi_imx->rx_buf) {
>> + int n_bytes = spi_imx->slave_burst % sizeof(val);
>> +
>> + if (!n_bytes)
>> + n_bytes = sizeof(val);
>> +
>> + memcpy(spi_imx->rx_buf,
>> + ((u8 *)&val) + sizeof(val) - n_bytes, n_bytes);
>> +
>> + spi_imx->rx_buf += n_bytes;
>> + spi_imx->slave_burst -= n_bytes;
>> + }
>> +}
>> +
>> +static void mx53_ecspi_tx_slave(struct spi_imx_data *spi_imx)
>> +{
>> + u32 val = 0;
>> + int n_bytes = spi_imx->count % sizeof(val);
>> +
>> + if (!n_bytes)
>> + n_bytes = sizeof(val);
>> +
>> + if (spi_imx->tx_buf) {
>> + memcpy(((u8 *)&val) + sizeof(val) - n_bytes,
>> + spi_imx->tx_buf, n_bytes);
>> + val = cpu_to_be32(val);
>> + spi_imx->tx_buf += n_bytes;
>> + }
>> +
>> + spi_imx->count -= n_bytes;
>> +
>> + writel(val, spi_imx->base + MXC_CSPITXDATA);
>> +}
>> +
>> /* MX51 eCSPI */
>> static unsigned int mx51_ecspi_clkdiv(struct spi_imx_data *spi_imx,
>> unsigned int fspi, unsigned int
> *fres)
>> @@ -427,6 +479,9 @@ static void mx51_ecspi_intctrl(struct spi_imx_data
> *spi_imx, int enable)
>> if (enable & MXC_INT_RR)
>> val |= MX51_ECSPI_INT_RREN;
>> + if (enable & MXC_INT_RDR)
>> + val |= MX51_ECSPI_INT_RDREN;
>> +
>> writel(val, spi_imx->base + MX51_ECSPI_INT);
>> }
>> @@ -439,6 +494,15 @@ static void mx51_ecspi_trigger(struct spi_imx_data
> *spi_imx)
>> writel(reg, spi_imx->base + MX51_ECSPI_CTRL);
>> }
>> +static void mx51_ecspi_disable(struct spi_imx_data *spi_imx)
>> +{
>> + u32 ctrl;
>> +
>> + ctrl = readl(spi_imx->base + MX51_ECSPI_CTRL);
>> + ctrl &= ~MX51_ECSPI_CTRL_ENABLE;
>> + writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
>> +}
>> +
>> static int mx51_ecspi_config(struct spi_device *spi)
>> {
>> struct spi_imx_data *spi_imx = spi_master_get_devdata(spi-
>> master);
>> @@ -446,14 +510,11 @@ static int mx51_ecspi_config(struct spi_device
> *spi)
>> u32 clk = spi_imx->speed_hz, delay, reg;
>> u32 cfg = readl(spi_imx->base + MX51_ECSPI_CONFIG);
>> - /* - * The hardware seems to have a race condition when changing modes. The -
>> * current assumption is that the selection of the channel arrives - * earlier in the
>> hardware than the mode bits when they are written at - * the same time. - * So set
>> master mode for all channels as we do not support slave mode. - */ - ctrl |=
>> MX51_ECSPI_CTRL_MODE_MASK; + /* set Master or Slave mode */ + if
>> (spi_imx->slave_mode) + ctrl &= ~MX51_ECSPI_CTRL_MODE_MASK; + else +
>> ctrl |= MX51_ECSPI_CTRL_MODE_MASK;
>>
>> /*
>> * Enable SPI_RDY handling (falling edge/level triggered).
>> @@ -468,9 +529,22 @@ static int mx51_ecspi_config(struct spi_device *spi)
>> /* set chip select to use */
>> ctrl |= MX51_ECSPI_CTRL_CS(spi->chip_select);
>> - ctrl |= (spi_imx->bits_per_word - 1) << MX51_ECSPI_CTRL_BL_OFFSET; + if
>> (spi_imx->slave_mode && is_imx53_ecspi(spi_imx)) + ctrl |= (spi_imx->slave_burst *
>> 8 - 1) + << MX51_ECSPI_CTRL_BL_OFFSET; + else + ctrl
>> |= (spi_imx->bits_per_word - 1) + << MX51_ECSPI_CTRL_BL_OFFSET;
>>
>> - cfg |= MX51_ECSPI_CONFIG_SBBCTRL(spi->chip_select); + /* + * eCSPI burst
>> completion by Chip Select signal in Slave mode + * is not functional for imx53 Soc,
>> config SPI burst completed when + * BURST_LENGTH + 1 bits are received + */ +
>> if (spi_imx->slave_mode && is_imx53_ecspi(spi_imx)) + cfg &=
>> ~MX51_ECSPI_CONFIG_SBBCTRL(spi->chip_select); + else + cfg |=
>> MX51_ECSPI_CONFIG_SBBCTRL(spi->chip_select);
>>
>> if (spi->mode & SPI_CPHA)
>> cfg |= MX51_ECSPI_CONFIG_SCLKPHA(spi->chip_select);
>> @@ -805,6 +879,7 @@ static struct spi_imx_devtype_data
> imx1_cspi_devtype_data = {
>> .fifo_size = 8, .has_dmamode = false, .dynamic_burst = false, + .has_slavemode =
>> false, .devtype = IMX1_CSPI,
>> };
>> @@ -817,6 +892,7 @@ static struct spi_imx_devtype_data
> imx21_cspi_devtype_data = {
>> .fifo_size = 8, .has_dmamode = false, .dynamic_burst = false, + .has_slavemode =
>> false, .devtype = IMX21_CSPI,
>> };
>> @@ -830,6 +906,7 @@ static struct spi_imx_devtype_data
> imx27_cspi_devtype_data = {
>> .fifo_size = 8, .has_dmamode = false, .dynamic_burst = false, + .has_slavemode =
>> false, .devtype = IMX27_CSPI,
>> };
>> @@ -842,6 +919,7 @@ static struct spi_imx_devtype_data
> imx31_cspi_devtype_data = {
>> .fifo_size = 8, .has_dmamode = false, .dynamic_burst = false, + .has_slavemode =
>> false, .devtype = IMX31_CSPI,
>> };
>> @@ -855,6 +933,7 @@ static struct spi_imx_devtype_data
> imx35_cspi_devtype_data = {
>> .fifo_size = 8, .has_dmamode = true, .dynamic_burst = false, + .has_slavemode =
>> false, .devtype = IMX35_CSPI,
>> };
>> @@ -867,6 +946,8 @@ static struct spi_imx_devtype_data
> imx51_ecspi_devtype_data = {
>> .fifo_size = 64,
>> .has_dmamode = true,
>> .dynamic_burst = true,
>> + .has_slavemode = true,
>> + .disable = mx51_ecspi_disable,
>> .devtype = IMX51_ECSPI,
>> };
>> @@ -878,6 +959,8 @@ static struct spi_imx_devtype_data
> imx53_ecspi_devtype_data = {
>> .reset = mx51_ecspi_reset,
>> .fifo_size = 64,
>> .has_dmamode = true,
>> + .has_slavemode = true,
>> + .disable = mx51_ecspi_disable,
>> .devtype = IMX53_ECSPI,
>> };
>> @@ -945,14 +1028,16 @@ static void spi_imx_push(struct spi_imx_data
> *spi_imx)
>> spi_imx->txfifo++;
>> }
>> - spi_imx->devtype_data->trigger(spi_imx);
>> + if (!spi_imx->slave_mode)
>> + spi_imx->devtype_data->trigger(spi_imx);
>> }
>>
>> static irqreturn_t spi_imx_isr(int irq, void *dev_id)
>> {
>> struct spi_imx_data *spi_imx = dev_id;
>> - while (spi_imx->devtype_data->rx_available(spi_imx)) {
>> + while (spi_imx->txfifo &&
>> + spi_imx->devtype_data->rx_available(spi_imx)) {
>> spi_imx->rx(spi_imx);
>> spi_imx->txfifo--;
>> }
>> @@ -1034,7 +1119,7 @@ static int spi_imx_setupxfer(struct spi_device
> *spi,
>> spi_imx->speed_hz = t->speed_hz;
>>
>> /* Initialize the functions for transfer */
>> - if (spi_imx->devtype_data->dynamic_burst) {
>> + if (spi_imx->devtype_data->dynamic_burst && !spi_imx->slave_mode)
> {
>> u32 mask;
>>
>> spi_imx->dynamic_burst = 0;
>> @@ -1078,6 +1163,12 @@ static int spi_imx_setupxfer(struct spi_device
> *spi,
>> return ret;
>> }
>> + if (is_imx53_ecspi(spi_imx) && spi_imx->slave_mode) {
>> + spi_imx->rx = mx53_ecspi_rx_slave;
>> + spi_imx->tx = mx53_ecspi_tx_slave;
>> + spi_imx->slave_burst = t->len;
>> + }
>> +
>> spi_imx->devtype_data->config(spi);
>>
>> return 0;
>> @@ -1262,11 +1353,61 @@ static int spi_imx_pio_transfer(struct spi_device
> *spi,
>> return transfer->len;
>> }
>> +static int spi_imx_pio_transfer_slave(struct spi_device *spi, +
>> struct spi_transfer *transfer) +{ + struct spi_imx_data *spi_imx =
>> spi_master_get_devdata(spi- master); + int ret = transfer->len; + + if
>> (is_imx53_ecspi(spi_imx) && + transfer->len > MX53_MAX_TRANSFER_BYTES) { +
>> dev_err(&spi->dev, "Transaction too big, max size is %d bytes\n", +
>> MX53_MAX_TRANSFER_BYTES); + return -EMSGSIZE; + } + + spi_imx->tx_buf
>> = transfer->tx_buf; + spi_imx->rx_buf = transfer->rx_buf; + spi_imx->count =
>> transfer->len; + spi_imx->txfifo = 0; + + reinit_completion(&spi_imx->xfer_done); +
>> spi_imx->slave_aborted = false; + + spi_imx_push(spi_imx); + +
>> spi_imx->devtype_data->intctrl(spi_imx, MXC_INT_TE | MXC_INT_RDR); + + if
>> (wait_for_completion_interruptible(&spi_imx->xfer_done) || + spi_imx->slave_aborted) {
>> + dev_dbg(&spi->dev, "interrupted\n"); + ret = -EINTR; + } + +
>> /* ecspi has a HW issue when works in Slave mode, + * after 64 words writtern to
>> TXFIFO, even TXFIFO becomes empty, + * ECSPI_TXDATA keeps shift out the last word data, +
>> * so we have to disable ECSPI when in slave mode after the + * transfer completes
>> + */ + if (spi_imx->devtype_data->disable) +
>> spi_imx->devtype_data->disable(spi_imx); + + return ret; +} +
>> static int spi_imx_transfer(struct spi_device *spi,
>> struct spi_transfer *transfer)
>> {
>> struct spi_imx_data *spi_imx = spi_master_get_devdata(spi-
>> master);
>>
>> + /* flush rxfifo before transfer */
>> + while (spi_imx->devtype_data->rx_available(spi_imx))
>> + spi_imx->rx(spi_imx);
>> +
>> + if (spi_imx->slave_mode)
>> + return spi_imx_pio_transfer_slave(spi, transfer);
>> +
>> if (spi_imx->usedma)
>> return spi_imx_dma_transfer(spi_imx, transfer);
>> else
>> @@ -1323,6 +1464,16 @@ spi_imx_unprepare_message(struct spi_master
> *master, struct spi_message *msg)
>> return 0;
>> }
>> +static int spi_imx_slave_abort(struct spi_master *master)
>> +{
>> + struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
>> +
>> + spi_imx->slave_aborted = true;
>> + complete(&spi_imx->xfer_done);
>> +
>> + return 0;
>> +}
>> +
>> static int spi_imx_probe(struct platform_device *pdev)
>> {
>> struct device_node *np = pdev->dev.of_node;
>> @@ -1334,13 +1485,23 @@ static int spi_imx_probe(struct platform_device
> *pdev)
>> struct spi_imx_data *spi_imx;
>> struct resource *res;
>> int i, ret, irq, spi_drctl;
>> + const struct spi_imx_devtype_data *devtype_data = of_id ? of_id-
>> data :
>> + (struct spi_imx_devtype_data *)pdev->id_entry-
>> driver_data;
>> + bool slave_mode;
>>
>> if (!np && !mxc_platform_info) {
>> dev_err(&pdev->dev, "can't get the platform data\n");
>> return -EINVAL;
>> }
>> - master = spi_alloc_master(&pdev->dev, sizeof(struct spi_imx_data)); + slave_mode =
>> devtype_data->has_slavemode && + of_property_read_bool(np, "spi-slave"); +
>> if (slave_mode) + master = spi_alloc_slave(&pdev->dev, +
>> sizeof(struct spi_imx_data)); + else + master =
>> spi_alloc_master(&pdev->dev, + sizeof(struct
>> spi_imx_data));
>> if (!master)
>> return -ENOMEM;
>> @@ -1358,9 +1519,9 @@ static int spi_imx_probe(struct platform_device
> *pdev)
>> spi_imx = spi_master_get_devdata(master);
>> spi_imx->bitbang.master = master;
>> spi_imx->dev = &pdev->dev;
>> + spi_imx->slave_mode = slave_mode;
>>
>> - spi_imx->devtype_data = of_id ? of_id->data :
>> - (struct spi_imx_devtype_data *)pdev->id_entry-
>> driver_data;
>> + spi_imx->devtype_data = devtype_data;
>>
>> if (mxc_platform_info) {
>> master->num_chipselect = mxc_platform_info-
>> num_chipselect;
>> @@ -1380,6 +1541,7 @@ static int spi_imx_probe(struct platform_device
> *pdev)
>> spi_imx->bitbang.master->cleanup = spi_imx_cleanup;
>> spi_imx->bitbang.master->prepare_message = spi_imx_prepare_message;
>> spi_imx->bitbang.master->unprepare_message =
> spi_imx_unprepare_message;
>> + spi_imx->bitbang.master->slave_abort = spi_imx_slave_abort;
>> spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA |
> SPI_CS_HIGH \
>> | SPI_NO_CS;
>> if (is_imx35_cspi(spi_imx) || is_imx51_ecspi(spi_imx) ||
>> @@ -1457,23 +1619,26 @@ static int spi_imx_probe(struct platform_device
> *pdev)
>> goto out_clk_put;
>> }
>> - if (!master->cs_gpios) {
>> - dev_err(&pdev->dev, "No CS GPIOs available\n");
>> - ret = -EINVAL;
>> - goto out_clk_put;
>> - }
>> -
>> - for (i = 0; i < master->num_chipselect; i++) {
>> - if (!gpio_is_valid(master->cs_gpios[i]))
>> - continue;
>> -
>> - ret = devm_gpio_request(&pdev->dev, master->cs_gpios[i],
>> - DRIVER_NAME);
>> - if (ret) {
>> - dev_err(&pdev->dev, "Can't get CS GPIO %i\n",
>> - master->cs_gpios[i]);
>> + if (!spi_imx->slave_mode) {
>> + if (!master->cs_gpios) {
>> + dev_err(&pdev->dev, "No CS GPIOs available\n");
>> + ret = -EINVAL;
>> goto out_clk_put;
>> }
>> + + for (i = 0; i < master->num_chipselect; i++) { + if
>> (!gpio_is_valid(master->cs_gpios[i])) + continue; + +
>> ret = devm_gpio_request(&pdev->dev, +
>> master->cs_gpios[i], + DRIVER_NAME); +
>> if (ret) { + dev_err(&pdev->dev, "Can't get CS GPIO
>> %i\n", + master->cs_gpios[i]); +
>> goto out_clk_put; + } + }
>> }
>>
>> dev_info(&pdev->dev, "probed\n");
>> --
>> 2.9.3
>>

Next message: Tejun Heo: "[GIT PULL] libata changes for v4.14-rc1"
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In reply to: Fabio Estevam: "Re: [PATCH linux-next v6 1/1] spi: imx: Add support for SPI Slave mode"
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