From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- drivers/spi/spi-dw-dma.c | 711 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 711 insertions(+) create mode 100644 drivers/spi/spi-dw-dma.c (limited to 'drivers/spi/spi-dw-dma.c') diff --git a/drivers/spi/spi-dw-dma.c b/drivers/spi/spi-dw-dma.c new file mode 100644 index 0000000000..0ecbb6c36e --- /dev/null +++ b/drivers/spi/spi-dw-dma.c @@ -0,0 +1,711 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Special handling for DW DMA core + * + * Copyright (c) 2009, 2014 Intel Corporation. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "spi-dw.h" + +#define DW_SPI_RX_BUSY 0 +#define DW_SPI_RX_BURST_LEVEL 16 +#define DW_SPI_TX_BUSY 1 +#define DW_SPI_TX_BURST_LEVEL 16 + +static bool dw_spi_dma_chan_filter(struct dma_chan *chan, void *param) +{ + struct dw_dma_slave *s = param; + + if (s->dma_dev != chan->device->dev) + return false; + + chan->private = s; + return true; +} + +static void dw_spi_dma_maxburst_init(struct dw_spi *dws) +{ + struct dma_slave_caps caps; + u32 max_burst, def_burst; + int ret; + + def_burst = dws->fifo_len / 2; + + ret = dma_get_slave_caps(dws->rxchan, &caps); + if (!ret && caps.max_burst) + max_burst = caps.max_burst; + else + max_burst = DW_SPI_RX_BURST_LEVEL; + + dws->rxburst = min(max_burst, def_burst); + dw_writel(dws, DW_SPI_DMARDLR, dws->rxburst - 1); + + ret = dma_get_slave_caps(dws->txchan, &caps); + if (!ret && caps.max_burst) + max_burst = caps.max_burst; + else + max_burst = DW_SPI_TX_BURST_LEVEL; + + /* + * Having a Rx DMA channel serviced with higher priority than a Tx DMA + * channel might not be enough to provide a well balanced DMA-based + * SPI transfer interface. There might still be moments when the Tx DMA + * channel is occasionally handled faster than the Rx DMA channel. + * That in its turn will eventually cause the SPI Rx FIFO overflow if + * SPI bus speed is high enough to fill the SPI Rx FIFO in before it's + * cleared by the Rx DMA channel. In order to fix the problem the Tx + * DMA activity is intentionally slowed down by limiting the SPI Tx + * FIFO depth with a value twice bigger than the Tx burst length. + */ + dws->txburst = min(max_burst, def_burst); + dw_writel(dws, DW_SPI_DMATDLR, dws->txburst); +} + +static int dw_spi_dma_caps_init(struct dw_spi *dws) +{ + struct dma_slave_caps tx, rx; + int ret; + + ret = dma_get_slave_caps(dws->txchan, &tx); + if (ret) + return ret; + + ret = dma_get_slave_caps(dws->rxchan, &rx); + if (ret) + return ret; + + if (!(tx.directions & BIT(DMA_MEM_TO_DEV) && + rx.directions & BIT(DMA_DEV_TO_MEM))) + return -ENXIO; + + if (tx.max_sg_burst > 0 && rx.max_sg_burst > 0) + dws->dma_sg_burst = min(tx.max_sg_burst, rx.max_sg_burst); + else if (tx.max_sg_burst > 0) + dws->dma_sg_burst = tx.max_sg_burst; + else if (rx.max_sg_burst > 0) + dws->dma_sg_burst = rx.max_sg_burst; + else + dws->dma_sg_burst = 0; + + /* + * Assuming both channels belong to the same DMA controller hence the + * peripheral side address width capabilities most likely would be + * the same. + */ + dws->dma_addr_widths = tx.dst_addr_widths & rx.src_addr_widths; + + return 0; +} + +static int dw_spi_dma_init_mfld(struct device *dev, struct dw_spi *dws) +{ + struct dw_dma_slave dma_tx = { .dst_id = 1 }, *tx = &dma_tx; + struct dw_dma_slave dma_rx = { .src_id = 0 }, *rx = &dma_rx; + struct pci_dev *dma_dev; + dma_cap_mask_t mask; + int ret = -EBUSY; + + /* + * Get pci device for DMA controller, currently it could only + * be the DMA controller of Medfield + */ + dma_dev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0827, NULL); + if (!dma_dev) + return -ENODEV; + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + + /* 1. Init rx channel */ + rx->dma_dev = &dma_dev->dev; + dws->rxchan = dma_request_channel(mask, dw_spi_dma_chan_filter, rx); + if (!dws->rxchan) + goto err_exit; + + /* 2. Init tx channel */ + tx->dma_dev = &dma_dev->dev; + dws->txchan = dma_request_channel(mask, dw_spi_dma_chan_filter, tx); + if (!dws->txchan) + goto free_rxchan; + + dws->host->dma_rx = dws->rxchan; + dws->host->dma_tx = dws->txchan; + + init_completion(&dws->dma_completion); + + ret = dw_spi_dma_caps_init(dws); + if (ret) + goto free_txchan; + + dw_spi_dma_maxburst_init(dws); + + pci_dev_put(dma_dev); + + return 0; + +free_txchan: + dma_release_channel(dws->txchan); + dws->txchan = NULL; +free_rxchan: + dma_release_channel(dws->rxchan); + dws->rxchan = NULL; +err_exit: + pci_dev_put(dma_dev); + return ret; +} + +static int dw_spi_dma_init_generic(struct device *dev, struct dw_spi *dws) +{ + int ret; + + dws->rxchan = dma_request_chan(dev, "rx"); + if (IS_ERR(dws->rxchan)) { + ret = PTR_ERR(dws->rxchan); + dws->rxchan = NULL; + goto err_exit; + } + + dws->txchan = dma_request_chan(dev, "tx"); + if (IS_ERR(dws->txchan)) { + ret = PTR_ERR(dws->txchan); + dws->txchan = NULL; + goto free_rxchan; + } + + dws->host->dma_rx = dws->rxchan; + dws->host->dma_tx = dws->txchan; + + init_completion(&dws->dma_completion); + + ret = dw_spi_dma_caps_init(dws); + if (ret) + goto free_txchan; + + dw_spi_dma_maxburst_init(dws); + + return 0; + +free_txchan: + dma_release_channel(dws->txchan); + dws->txchan = NULL; +free_rxchan: + dma_release_channel(dws->rxchan); + dws->rxchan = NULL; +err_exit: + return ret; +} + +static void dw_spi_dma_exit(struct dw_spi *dws) +{ + if (dws->txchan) { + dmaengine_terminate_sync(dws->txchan); + dma_release_channel(dws->txchan); + } + + if (dws->rxchan) { + dmaengine_terminate_sync(dws->rxchan); + dma_release_channel(dws->rxchan); + } +} + +static irqreturn_t dw_spi_dma_transfer_handler(struct dw_spi *dws) +{ + dw_spi_check_status(dws, false); + + complete(&dws->dma_completion); + + return IRQ_HANDLED; +} + +static enum dma_slave_buswidth dw_spi_dma_convert_width(u8 n_bytes) +{ + switch (n_bytes) { + case 1: + return DMA_SLAVE_BUSWIDTH_1_BYTE; + case 2: + return DMA_SLAVE_BUSWIDTH_2_BYTES; + case 4: + return DMA_SLAVE_BUSWIDTH_4_BYTES; + default: + return DMA_SLAVE_BUSWIDTH_UNDEFINED; + } +} + +static bool dw_spi_can_dma(struct spi_controller *host, + struct spi_device *spi, struct spi_transfer *xfer) +{ + struct dw_spi *dws = spi_controller_get_devdata(host); + enum dma_slave_buswidth dma_bus_width; + + if (xfer->len <= dws->fifo_len) + return false; + + dma_bus_width = dw_spi_dma_convert_width(dws->n_bytes); + + return dws->dma_addr_widths & BIT(dma_bus_width); +} + +static int dw_spi_dma_wait(struct dw_spi *dws, unsigned int len, u32 speed) +{ + unsigned long long ms; + + ms = len * MSEC_PER_SEC * BITS_PER_BYTE; + do_div(ms, speed); + ms += ms + 200; + + if (ms > UINT_MAX) + ms = UINT_MAX; + + ms = wait_for_completion_timeout(&dws->dma_completion, + msecs_to_jiffies(ms)); + + if (ms == 0) { + dev_err(&dws->host->cur_msg->spi->dev, + "DMA transaction timed out\n"); + return -ETIMEDOUT; + } + + return 0; +} + +static inline bool dw_spi_dma_tx_busy(struct dw_spi *dws) +{ + return !(dw_readl(dws, DW_SPI_SR) & DW_SPI_SR_TF_EMPT); +} + +static int dw_spi_dma_wait_tx_done(struct dw_spi *dws, + struct spi_transfer *xfer) +{ + int retry = DW_SPI_WAIT_RETRIES; + struct spi_delay delay; + u32 nents; + + nents = dw_readl(dws, DW_SPI_TXFLR); + delay.unit = SPI_DELAY_UNIT_SCK; + delay.value = nents * dws->n_bytes * BITS_PER_BYTE; + + while (dw_spi_dma_tx_busy(dws) && retry--) + spi_delay_exec(&delay, xfer); + + if (retry < 0) { + dev_err(&dws->host->dev, "Tx hanged up\n"); + return -EIO; + } + + return 0; +} + +/* + * dws->dma_chan_busy is set before the dma transfer starts, callback for tx + * channel will clear a corresponding bit. + */ +static void dw_spi_dma_tx_done(void *arg) +{ + struct dw_spi *dws = arg; + + clear_bit(DW_SPI_TX_BUSY, &dws->dma_chan_busy); + if (test_bit(DW_SPI_RX_BUSY, &dws->dma_chan_busy)) + return; + + complete(&dws->dma_completion); +} + +static int dw_spi_dma_config_tx(struct dw_spi *dws) +{ + struct dma_slave_config txconf; + + memset(&txconf, 0, sizeof(txconf)); + txconf.direction = DMA_MEM_TO_DEV; + txconf.dst_addr = dws->dma_addr; + txconf.dst_maxburst = dws->txburst; + txconf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + txconf.dst_addr_width = dw_spi_dma_convert_width(dws->n_bytes); + txconf.device_fc = false; + + return dmaengine_slave_config(dws->txchan, &txconf); +} + +static int dw_spi_dma_submit_tx(struct dw_spi *dws, struct scatterlist *sgl, + unsigned int nents) +{ + struct dma_async_tx_descriptor *txdesc; + dma_cookie_t cookie; + int ret; + + txdesc = dmaengine_prep_slave_sg(dws->txchan, sgl, nents, + DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!txdesc) + return -ENOMEM; + + txdesc->callback = dw_spi_dma_tx_done; + txdesc->callback_param = dws; + + cookie = dmaengine_submit(txdesc); + ret = dma_submit_error(cookie); + if (ret) { + dmaengine_terminate_sync(dws->txchan); + return ret; + } + + set_bit(DW_SPI_TX_BUSY, &dws->dma_chan_busy); + + return 0; +} + +static inline bool dw_spi_dma_rx_busy(struct dw_spi *dws) +{ + return !!(dw_readl(dws, DW_SPI_SR) & DW_SPI_SR_RF_NOT_EMPT); +} + +static int dw_spi_dma_wait_rx_done(struct dw_spi *dws) +{ + int retry = DW_SPI_WAIT_RETRIES; + struct spi_delay delay; + unsigned long ns, us; + u32 nents; + + /* + * It's unlikely that DMA engine is still doing the data fetching, but + * if it's let's give it some reasonable time. The timeout calculation + * is based on the synchronous APB/SSI reference clock rate, on a + * number of data entries left in the Rx FIFO, times a number of clock + * periods normally needed for a single APB read/write transaction + * without PREADY signal utilized (which is true for the DW APB SSI + * controller). + */ + nents = dw_readl(dws, DW_SPI_RXFLR); + ns = 4U * NSEC_PER_SEC / dws->max_freq * nents; + if (ns <= NSEC_PER_USEC) { + delay.unit = SPI_DELAY_UNIT_NSECS; + delay.value = ns; + } else { + us = DIV_ROUND_UP(ns, NSEC_PER_USEC); + delay.unit = SPI_DELAY_UNIT_USECS; + delay.value = clamp_val(us, 0, USHRT_MAX); + } + + while (dw_spi_dma_rx_busy(dws) && retry--) + spi_delay_exec(&delay, NULL); + + if (retry < 0) { + dev_err(&dws->host->dev, "Rx hanged up\n"); + return -EIO; + } + + return 0; +} + +/* + * dws->dma_chan_busy is set before the dma transfer starts, callback for rx + * channel will clear a corresponding bit. + */ +static void dw_spi_dma_rx_done(void *arg) +{ + struct dw_spi *dws = arg; + + clear_bit(DW_SPI_RX_BUSY, &dws->dma_chan_busy); + if (test_bit(DW_SPI_TX_BUSY, &dws->dma_chan_busy)) + return; + + complete(&dws->dma_completion); +} + +static int dw_spi_dma_config_rx(struct dw_spi *dws) +{ + struct dma_slave_config rxconf; + + memset(&rxconf, 0, sizeof(rxconf)); + rxconf.direction = DMA_DEV_TO_MEM; + rxconf.src_addr = dws->dma_addr; + rxconf.src_maxburst = dws->rxburst; + rxconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + rxconf.src_addr_width = dw_spi_dma_convert_width(dws->n_bytes); + rxconf.device_fc = false; + + return dmaengine_slave_config(dws->rxchan, &rxconf); +} + +static int dw_spi_dma_submit_rx(struct dw_spi *dws, struct scatterlist *sgl, + unsigned int nents) +{ + struct dma_async_tx_descriptor *rxdesc; + dma_cookie_t cookie; + int ret; + + rxdesc = dmaengine_prep_slave_sg(dws->rxchan, sgl, nents, + DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!rxdesc) + return -ENOMEM; + + rxdesc->callback = dw_spi_dma_rx_done; + rxdesc->callback_param = dws; + + cookie = dmaengine_submit(rxdesc); + ret = dma_submit_error(cookie); + if (ret) { + dmaengine_terminate_sync(dws->rxchan); + return ret; + } + + set_bit(DW_SPI_RX_BUSY, &dws->dma_chan_busy); + + return 0; +} + +static int dw_spi_dma_setup(struct dw_spi *dws, struct spi_transfer *xfer) +{ + u16 imr, dma_ctrl; + int ret; + + if (!xfer->tx_buf) + return -EINVAL; + + /* Setup DMA channels */ + ret = dw_spi_dma_config_tx(dws); + if (ret) + return ret; + + if (xfer->rx_buf) { + ret = dw_spi_dma_config_rx(dws); + if (ret) + return ret; + } + + /* Set the DMA handshaking interface */ + dma_ctrl = DW_SPI_DMACR_TDMAE; + if (xfer->rx_buf) + dma_ctrl |= DW_SPI_DMACR_RDMAE; + dw_writel(dws, DW_SPI_DMACR, dma_ctrl); + + /* Set the interrupt mask */ + imr = DW_SPI_INT_TXOI; + if (xfer->rx_buf) + imr |= DW_SPI_INT_RXUI | DW_SPI_INT_RXOI; + dw_spi_umask_intr(dws, imr); + + reinit_completion(&dws->dma_completion); + + dws->transfer_handler = dw_spi_dma_transfer_handler; + + return 0; +} + +static int dw_spi_dma_transfer_all(struct dw_spi *dws, + struct spi_transfer *xfer) +{ + int ret; + + /* Submit the DMA Tx transfer */ + ret = dw_spi_dma_submit_tx(dws, xfer->tx_sg.sgl, xfer->tx_sg.nents); + if (ret) + goto err_clear_dmac; + + /* Submit the DMA Rx transfer if required */ + if (xfer->rx_buf) { + ret = dw_spi_dma_submit_rx(dws, xfer->rx_sg.sgl, + xfer->rx_sg.nents); + if (ret) + goto err_clear_dmac; + + /* rx must be started before tx due to spi instinct */ + dma_async_issue_pending(dws->rxchan); + } + + dma_async_issue_pending(dws->txchan); + + ret = dw_spi_dma_wait(dws, xfer->len, xfer->effective_speed_hz); + +err_clear_dmac: + dw_writel(dws, DW_SPI_DMACR, 0); + + return ret; +} + +/* + * In case if at least one of the requested DMA channels doesn't support the + * hardware accelerated SG list entries traverse, the DMA driver will most + * likely work that around by performing the IRQ-based SG list entries + * resubmission. That might and will cause a problem if the DMA Tx channel is + * recharged and re-executed before the Rx DMA channel. Due to + * non-deterministic IRQ-handler execution latency the DMA Tx channel will + * start pushing data to the SPI bus before the Rx DMA channel is even + * reinitialized with the next inbound SG list entry. By doing so the DMA Tx + * channel will implicitly start filling the DW APB SSI Rx FIFO up, which while + * the DMA Rx channel being recharged and re-executed will eventually be + * overflown. + * + * In order to solve the problem we have to feed the DMA engine with SG list + * entries one-by-one. It shall keep the DW APB SSI Tx and Rx FIFOs + * synchronized and prevent the Rx FIFO overflow. Since in general the tx_sg + * and rx_sg lists may have different number of entries of different lengths + * (though total length should match) let's virtually split the SG-lists to the + * set of DMA transfers, which length is a minimum of the ordered SG-entries + * lengths. An ASCII-sketch of the implemented algo is following: + * xfer->len + * |___________| + * tx_sg list: |___|____|__| + * rx_sg list: |_|____|____| + * DMA transfers: |_|_|__|_|__| + * + * Note in order to have this workaround solving the denoted problem the DMA + * engine driver should properly initialize the max_sg_burst capability and set + * the DMA device max segment size parameter with maximum data block size the + * DMA engine supports. + */ + +static int dw_spi_dma_transfer_one(struct dw_spi *dws, + struct spi_transfer *xfer) +{ + struct scatterlist *tx_sg = NULL, *rx_sg = NULL, tx_tmp, rx_tmp; + unsigned int tx_len = 0, rx_len = 0; + unsigned int base, len; + int ret; + + sg_init_table(&tx_tmp, 1); + sg_init_table(&rx_tmp, 1); + + for (base = 0, len = 0; base < xfer->len; base += len) { + /* Fetch next Tx DMA data chunk */ + if (!tx_len) { + tx_sg = !tx_sg ? &xfer->tx_sg.sgl[0] : sg_next(tx_sg); + sg_dma_address(&tx_tmp) = sg_dma_address(tx_sg); + tx_len = sg_dma_len(tx_sg); + } + + /* Fetch next Rx DMA data chunk */ + if (!rx_len) { + rx_sg = !rx_sg ? &xfer->rx_sg.sgl[0] : sg_next(rx_sg); + sg_dma_address(&rx_tmp) = sg_dma_address(rx_sg); + rx_len = sg_dma_len(rx_sg); + } + + len = min(tx_len, rx_len); + + sg_dma_len(&tx_tmp) = len; + sg_dma_len(&rx_tmp) = len; + + /* Submit DMA Tx transfer */ + ret = dw_spi_dma_submit_tx(dws, &tx_tmp, 1); + if (ret) + break; + + /* Submit DMA Rx transfer */ + ret = dw_spi_dma_submit_rx(dws, &rx_tmp, 1); + if (ret) + break; + + /* Rx must be started before Tx due to SPI instinct */ + dma_async_issue_pending(dws->rxchan); + + dma_async_issue_pending(dws->txchan); + + /* + * Here we only need to wait for the DMA transfer to be + * finished since SPI controller is kept enabled during the + * procedure this loop implements and there is no risk to lose + * data left in the Tx/Rx FIFOs. + */ + ret = dw_spi_dma_wait(dws, len, xfer->effective_speed_hz); + if (ret) + break; + + reinit_completion(&dws->dma_completion); + + sg_dma_address(&tx_tmp) += len; + sg_dma_address(&rx_tmp) += len; + tx_len -= len; + rx_len -= len; + } + + dw_writel(dws, DW_SPI_DMACR, 0); + + return ret; +} + +static int dw_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer) +{ + unsigned int nents; + int ret; + + nents = max(xfer->tx_sg.nents, xfer->rx_sg.nents); + + /* + * Execute normal DMA-based transfer (which submits the Rx and Tx SG + * lists directly to the DMA engine at once) if either full hardware + * accelerated SG list traverse is supported by both channels, or the + * Tx-only SPI transfer is requested, or the DMA engine is capable to + * handle both SG lists on hardware accelerated basis. + */ + if (!dws->dma_sg_burst || !xfer->rx_buf || nents <= dws->dma_sg_burst) + ret = dw_spi_dma_transfer_all(dws, xfer); + else + ret = dw_spi_dma_transfer_one(dws, xfer); + if (ret) + return ret; + + if (dws->host->cur_msg->status == -EINPROGRESS) { + ret = dw_spi_dma_wait_tx_done(dws, xfer); + if (ret) + return ret; + } + + if (xfer->rx_buf && dws->host->cur_msg->status == -EINPROGRESS) + ret = dw_spi_dma_wait_rx_done(dws); + + return ret; +} + +static void dw_spi_dma_stop(struct dw_spi *dws) +{ + if (test_bit(DW_SPI_TX_BUSY, &dws->dma_chan_busy)) { + dmaengine_terminate_sync(dws->txchan); + clear_bit(DW_SPI_TX_BUSY, &dws->dma_chan_busy); + } + if (test_bit(DW_SPI_RX_BUSY, &dws->dma_chan_busy)) { + dmaengine_terminate_sync(dws->rxchan); + clear_bit(DW_SPI_RX_BUSY, &dws->dma_chan_busy); + } +} + +static const struct dw_spi_dma_ops dw_spi_dma_mfld_ops = { + .dma_init = dw_spi_dma_init_mfld, + .dma_exit = dw_spi_dma_exit, + .dma_setup = dw_spi_dma_setup, + .can_dma = dw_spi_can_dma, + .dma_transfer = dw_spi_dma_transfer, + .dma_stop = dw_spi_dma_stop, +}; + +void dw_spi_dma_setup_mfld(struct dw_spi *dws) +{ + dws->dma_ops = &dw_spi_dma_mfld_ops; +} +EXPORT_SYMBOL_NS_GPL(dw_spi_dma_setup_mfld, SPI_DW_CORE); + +static const struct dw_spi_dma_ops dw_spi_dma_generic_ops = { + .dma_init = dw_spi_dma_init_generic, + .dma_exit = dw_spi_dma_exit, + .dma_setup = dw_spi_dma_setup, + .can_dma = dw_spi_can_dma, + .dma_transfer = dw_spi_dma_transfer, + .dma_stop = dw_spi_dma_stop, +}; + +void dw_spi_dma_setup_generic(struct dw_spi *dws) +{ + dws->dma_ops = &dw_spi_dma_generic_ops; +} +EXPORT_SYMBOL_NS_GPL(dw_spi_dma_setup_generic, SPI_DW_CORE); -- cgit v1.2.3