// SPDX-License-Identifier: GPL-2.0-only /* * LocalPlus Bus FIFO driver for the Freescale MPC52xx. * * Copyright (C) 2009 Secret Lab Technologies Ltd. * * Todo: * - Add support for multiple requests to be queued. */ #include #include #include #include #include #include #include #include #include #include #include #include #include MODULE_AUTHOR("Grant Likely "); MODULE_DESCRIPTION("MPC5200 LocalPlus FIFO device driver"); MODULE_LICENSE("GPL"); #define LPBFIFO_REG_PACKET_SIZE (0x00) #define LPBFIFO_REG_START_ADDRESS (0x04) #define LPBFIFO_REG_CONTROL (0x08) #define LPBFIFO_REG_ENABLE (0x0C) #define LPBFIFO_REG_BYTES_DONE_STATUS (0x14) #define LPBFIFO_REG_FIFO_DATA (0x40) #define LPBFIFO_REG_FIFO_STATUS (0x44) #define LPBFIFO_REG_FIFO_CONTROL (0x48) #define LPBFIFO_REG_FIFO_ALARM (0x4C) struct mpc52xx_lpbfifo { struct device *dev; phys_addr_t regs_phys; void __iomem *regs; int irq; spinlock_t lock; struct bcom_task *bcom_tx_task; struct bcom_task *bcom_rx_task; struct bcom_task *bcom_cur_task; /* Current state data */ struct mpc52xx_lpbfifo_request *req; int dma_irqs_enabled; }; /* The MPC5200 has only one fifo, so only need one instance structure */ static struct mpc52xx_lpbfifo lpbfifo; /** * mpc52xx_lpbfifo_kick - Trigger the next block of data to be transferred */ static void mpc52xx_lpbfifo_kick(struct mpc52xx_lpbfifo_request *req) { size_t transfer_size = req->size - req->pos; struct bcom_bd *bd; void __iomem *reg; u32 *data; int i; int bit_fields; int dma = !(req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA); int write = req->flags & MPC52XX_LPBFIFO_FLAG_WRITE; int poll_dma = req->flags & MPC52XX_LPBFIFO_FLAG_POLL_DMA; /* Set and clear the reset bits; is good practice in User Manual */ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000); /* set master enable bit */ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x00000001); if (!dma) { /* While the FIFO can be setup for transfer sizes as large as * 16M-1, the FIFO itself is only 512 bytes deep and it does * not generate interrupts for FIFO full events (only transfer * complete will raise an IRQ). Therefore when not using * Bestcomm to drive the FIFO it needs to either be polled, or * transfers need to constrained to the size of the fifo. * * This driver restricts the size of the transfer */ if (transfer_size > 512) transfer_size = 512; /* Load the FIFO with data */ if (write) { reg = lpbfifo.regs + LPBFIFO_REG_FIFO_DATA; data = req->data + req->pos; for (i = 0; i < transfer_size; i += 4) out_be32(reg, *data++); } /* Unmask both error and completion irqs */ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x00000301); } else { /* Choose the correct direction * * Configure the watermarks so DMA will always complete correctly. * It may be worth experimenting with the ALARM value to see if * there is a performance impacit. However, if it is wrong there * is a risk of DMA not transferring the last chunk of data */ if (write) { out_be32(lpbfifo.regs + LPBFIFO_REG_FIFO_ALARM, 0x1e4); out_8(lpbfifo.regs + LPBFIFO_REG_FIFO_CONTROL, 7); lpbfifo.bcom_cur_task = lpbfifo.bcom_tx_task; } else { out_be32(lpbfifo.regs + LPBFIFO_REG_FIFO_ALARM, 0x1ff); out_8(lpbfifo.regs + LPBFIFO_REG_FIFO_CONTROL, 0); lpbfifo.bcom_cur_task = lpbfifo.bcom_rx_task; if (poll_dma) { if (lpbfifo.dma_irqs_enabled) { disable_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task)); lpbfifo.dma_irqs_enabled = 0; } } else { if (!lpbfifo.dma_irqs_enabled) { enable_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task)); lpbfifo.dma_irqs_enabled = 1; } } } bd = bcom_prepare_next_buffer(lpbfifo.bcom_cur_task); bd->status = transfer_size; if (!write) { /* * In the DMA read case, the DMA doesn't complete, * possibly due to incorrect watermarks in the ALARM * and CONTROL regs. For now instead of trying to * determine the right watermarks that will make this * work, just increase the number of bytes the FIFO is * expecting. * * When submitting another operation, the FIFO will get * reset, so the condition of the FIFO waiting for a * non-existent 4 bytes will get cleared. */ transfer_size += 4; /* BLECH! */ } bd->data[0] = req->data_phys + req->pos; bcom_submit_next_buffer(lpbfifo.bcom_cur_task, NULL); /* error irq & master enabled bit */ bit_fields = 0x00000201; /* Unmask irqs */ if (write && (!poll_dma)) bit_fields |= 0x00000100; /* completion irq too */ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, bit_fields); } /* Set transfer size, width, chip select and READ mode */ out_be32(lpbfifo.regs + LPBFIFO_REG_START_ADDRESS, req->offset + req->pos); out_be32(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, transfer_size); bit_fields = req->cs << 24 | 0x000008; if (!write) bit_fields |= 0x010000; /* read mode */ out_be32(lpbfifo.regs + LPBFIFO_REG_CONTROL, bit_fields); /* Kick it off */ if (!lpbfifo.req->defer_xfer_start) out_8(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, 0x01); if (dma) bcom_enable(lpbfifo.bcom_cur_task); } /** * mpc52xx_lpbfifo_irq - IRQ handler for LPB FIFO * * On transmit, the dma completion irq triggers before the fifo completion * triggers. Handle the dma completion here instead of the LPB FIFO Bestcomm * task completion irq because everything is not really done until the LPB FIFO * completion irq triggers. * * In other words: * For DMA, on receive, the "Fat Lady" is the bestcom completion irq. on * transmit, the fifo completion irq is the "Fat Lady". The opera (or in this * case the DMA/FIFO operation) is not finished until the "Fat Lady" sings. * * Reasons for entering this routine: * 1) PIO mode rx and tx completion irq * 2) DMA interrupt mode tx completion irq * 3) DMA polled mode tx * * Exit conditions: * 1) Transfer aborted * 2) FIFO complete without DMA; more data to do * 3) FIFO complete without DMA; all data transferred * 4) FIFO complete using DMA * * Condition 1 can occur regardless of whether or not DMA is used. * It requires executing the callback to report the error and exiting * immediately. * * Condition 2 requires programming the FIFO with the next block of data * * Condition 3 requires executing the callback to report completion * * Condition 4 means the same as 3, except that we also retrieve the bcom * buffer so DMA doesn't get clogged up. * * To make things trickier, the spinlock must be dropped before * executing the callback, otherwise we could end up with a deadlock * or nested spinlock condition. The out path is non-trivial, so * extra fiddling is done to make sure all paths lead to the same * outbound code. */ static irqreturn_t mpc52xx_lpbfifo_irq(int irq, void *dev_id) { struct mpc52xx_lpbfifo_request *req; u32 status = in_8(lpbfifo.regs + LPBFIFO_REG_BYTES_DONE_STATUS); void __iomem *reg; u32 *data; int count, i; int do_callback = 0; u32 ts; unsigned long flags; int dma, write, poll_dma; spin_lock_irqsave(&lpbfifo.lock, flags); ts = mftb(); req = lpbfifo.req; if (!req) { spin_unlock_irqrestore(&lpbfifo.lock, flags); pr_err("bogus LPBFIFO IRQ\n"); return IRQ_HANDLED; } dma = !(req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA); write = req->flags & MPC52XX_LPBFIFO_FLAG_WRITE; poll_dma = req->flags & MPC52XX_LPBFIFO_FLAG_POLL_DMA; if (dma && !write) { spin_unlock_irqrestore(&lpbfifo.lock, flags); pr_err("bogus LPBFIFO IRQ (dma and not writing)\n"); return IRQ_HANDLED; } if ((status & 0x01) == 0) { goto out; } /* check abort bit */ if (status & 0x10) { out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000); do_callback = 1; goto out; } /* Read result from hardware */ count = in_be32(lpbfifo.regs + LPBFIFO_REG_BYTES_DONE_STATUS); count &= 0x00ffffff; if (!dma && !write) { /* copy the data out of the FIFO */ reg = lpbfifo.regs + LPBFIFO_REG_FIFO_DATA; data = req->data + req->pos; for (i = 0; i < count; i += 4) *data++ = in_be32(reg); } /* Update transfer position and count */ req->pos += count; /* Decide what to do next */ if (req->size - req->pos) mpc52xx_lpbfifo_kick(req); /* more work to do */ else do_callback = 1; out: /* Clear the IRQ */ out_8(lpbfifo.regs + LPBFIFO_REG_BYTES_DONE_STATUS, 0x01); if (dma && (status & 0x11)) { /* * Count the DMA as complete only when the FIFO completion * status or abort bits are set. * * (status & 0x01) should always be the case except sometimes * when using polled DMA. * * (status & 0x10) {transfer aborted}: This case needs more * testing. */ bcom_retrieve_buffer(lpbfifo.bcom_cur_task, &status, NULL); } req->last_byte = ((u8 *)req->data)[req->size - 1]; /* When the do_callback flag is set; it means the transfer is finished * so set the FIFO as idle */ if (do_callback) lpbfifo.req = NULL; if (irq != 0) /* don't increment on polled case */ req->irq_count++; req->irq_ticks += mftb() - ts; spin_unlock_irqrestore(&lpbfifo.lock, flags); /* Spinlock is released; it is now safe to call the callback */ if (do_callback && req->callback) req->callback(req); return IRQ_HANDLED; } /** * mpc52xx_lpbfifo_bcom_irq - IRQ handler for LPB FIFO Bestcomm task * * Only used when receiving data. */ static irqreturn_t mpc52xx_lpbfifo_bcom_irq(int irq, void *dev_id) { struct mpc52xx_lpbfifo_request *req; unsigned long flags; u32 status; u32 ts; spin_lock_irqsave(&lpbfifo.lock, flags); ts = mftb(); req = lpbfifo.req; if (!req || (req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA)) { spin_unlock_irqrestore(&lpbfifo.lock, flags); return IRQ_HANDLED; } if (irq != 0) /* don't increment on polled case */ req->irq_count++; if (!bcom_buffer_done(lpbfifo.bcom_cur_task)) { spin_unlock_irqrestore(&lpbfifo.lock, flags); req->buffer_not_done_cnt++; if ((req->buffer_not_done_cnt % 1000) == 0) pr_err("transfer stalled\n"); return IRQ_HANDLED; } bcom_retrieve_buffer(lpbfifo.bcom_cur_task, &status, NULL); req->last_byte = ((u8 *)req->data)[req->size - 1]; req->pos = status & 0x00ffffff; /* Mark the FIFO as idle */ lpbfifo.req = NULL; /* Release the lock before calling out to the callback. */ req->irq_ticks += mftb() - ts; spin_unlock_irqrestore(&lpbfifo.lock, flags); if (req->callback) req->callback(req); return IRQ_HANDLED; } /** * mpc52xx_lpbfifo_bcom_poll - Poll for DMA completion */ void mpc52xx_lpbfifo_poll(void) { struct mpc52xx_lpbfifo_request *req = lpbfifo.req; int dma = !(req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA); int write = req->flags & MPC52XX_LPBFIFO_FLAG_WRITE; /* * For more information, see comments on the "Fat Lady" */ if (dma && write) mpc52xx_lpbfifo_irq(0, NULL); else mpc52xx_lpbfifo_bcom_irq(0, NULL); } EXPORT_SYMBOL(mpc52xx_lpbfifo_poll); /** * mpc52xx_lpbfifo_submit - Submit an LPB FIFO transfer request. * @req: Pointer to request structure */ int mpc52xx_lpbfifo_submit(struct mpc52xx_lpbfifo_request *req) { unsigned long flags; if (!lpbfifo.regs) return -ENODEV; spin_lock_irqsave(&lpbfifo.lock, flags); /* If the req pointer is already set, then a transfer is in progress */ if (lpbfifo.req) { spin_unlock_irqrestore(&lpbfifo.lock, flags); return -EBUSY; } /* Setup the transfer */ lpbfifo.req = req; req->irq_count = 0; req->irq_ticks = 0; req->buffer_not_done_cnt = 0; req->pos = 0; mpc52xx_lpbfifo_kick(req); spin_unlock_irqrestore(&lpbfifo.lock, flags); return 0; } EXPORT_SYMBOL(mpc52xx_lpbfifo_submit); int mpc52xx_lpbfifo_start_xfer(struct mpc52xx_lpbfifo_request *req) { unsigned long flags; if (!lpbfifo.regs) return -ENODEV; spin_lock_irqsave(&lpbfifo.lock, flags); /* * If the req pointer is already set and a transfer was * started on submit, then this transfer is in progress */ if (lpbfifo.req && !lpbfifo.req->defer_xfer_start) { spin_unlock_irqrestore(&lpbfifo.lock, flags); return -EBUSY; } /* * If the req was previously submitted but not * started, start it now */ if (lpbfifo.req && lpbfifo.req == req && lpbfifo.req->defer_xfer_start) { out_8(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, 0x01); } spin_unlock_irqrestore(&lpbfifo.lock, flags); return 0; } EXPORT_SYMBOL(mpc52xx_lpbfifo_start_xfer); void mpc52xx_lpbfifo_abort(struct mpc52xx_lpbfifo_request *req) { unsigned long flags; spin_lock_irqsave(&lpbfifo.lock, flags); if (lpbfifo.req == req) { /* Put it into reset and clear the state */ bcom_gen_bd_rx_reset(lpbfifo.bcom_rx_task); bcom_gen_bd_tx_reset(lpbfifo.bcom_tx_task); out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000); lpbfifo.req = NULL; } spin_unlock_irqrestore(&lpbfifo.lock, flags); } EXPORT_SYMBOL(mpc52xx_lpbfifo_abort); static int mpc52xx_lpbfifo_probe(struct platform_device *op) { struct resource res; int rc = -ENOMEM; if (lpbfifo.dev != NULL) return -ENOSPC; lpbfifo.irq = irq_of_parse_and_map(op->dev.of_node, 0); if (!lpbfifo.irq) return -ENODEV; if (of_address_to_resource(op->dev.of_node, 0, &res)) return -ENODEV; lpbfifo.regs_phys = res.start; lpbfifo.regs = of_iomap(op->dev.of_node, 0); if (!lpbfifo.regs) return -ENOMEM; spin_lock_init(&lpbfifo.lock); /* Put FIFO into reset */ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000); /* Register the interrupt handler */ rc = request_irq(lpbfifo.irq, mpc52xx_lpbfifo_irq, 0, "mpc52xx-lpbfifo", &lpbfifo); if (rc) goto err_irq; /* Request the Bestcomm receive (fifo --> memory) task and IRQ */ lpbfifo.bcom_rx_task = bcom_gen_bd_rx_init(2, res.start + LPBFIFO_REG_FIFO_DATA, BCOM_INITIATOR_SCLPC, BCOM_IPR_SCLPC, 16*1024*1024); if (!lpbfifo.bcom_rx_task) goto err_bcom_rx; rc = request_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task), mpc52xx_lpbfifo_bcom_irq, 0, "mpc52xx-lpbfifo-rx", &lpbfifo); if (rc) goto err_bcom_rx_irq; lpbfifo.dma_irqs_enabled = 1; /* Request the Bestcomm transmit (memory --> fifo) task and IRQ */ lpbfifo.bcom_tx_task = bcom_gen_bd_tx_init(2, res.start + LPBFIFO_REG_FIFO_DATA, BCOM_INITIATOR_SCLPC, BCOM_IPR_SCLPC); if (!lpbfifo.bcom_tx_task) goto err_bcom_tx; lpbfifo.dev = &op->dev; return 0; err_bcom_tx: free_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task), &lpbfifo); err_bcom_rx_irq: bcom_gen_bd_rx_release(lpbfifo.bcom_rx_task); err_bcom_rx: free_irq(lpbfifo.irq, &lpbfifo); err_irq: iounmap(lpbfifo.regs); lpbfifo.regs = NULL; dev_err(&op->dev, "mpc52xx_lpbfifo_probe() failed\n"); return -ENODEV; } static int mpc52xx_lpbfifo_remove(struct platform_device *op) { if (lpbfifo.dev != &op->dev) return 0; /* Put FIFO in reset */ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000); /* Release the bestcomm transmit task */ free_irq(bcom_get_task_irq(lpbfifo.bcom_tx_task), &lpbfifo); bcom_gen_bd_tx_release(lpbfifo.bcom_tx_task); /* Release the bestcomm receive task */ free_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task), &lpbfifo); bcom_gen_bd_rx_release(lpbfifo.bcom_rx_task); free_irq(lpbfifo.irq, &lpbfifo); iounmap(lpbfifo.regs); lpbfifo.regs = NULL; lpbfifo.dev = NULL; return 0; } static const struct of_device_id mpc52xx_lpbfifo_match[] = { { .compatible = "fsl,mpc5200-lpbfifo", }, {}, }; MODULE_DEVICE_TABLE(of, mpc52xx_lpbfifo_match); static struct platform_driver mpc52xx_lpbfifo_driver = { .driver = { .name = "mpc52xx-lpbfifo", .of_match_table = mpc52xx_lpbfifo_match, }, .probe = mpc52xx_lpbfifo_probe, .remove = mpc52xx_lpbfifo_remove, }; module_platform_driver(mpc52xx_lpbfifo_driver);