diff options
Diffstat (limited to 'arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c')
| -rw-r--r-- | arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c | 560 |
1 files changed, 560 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c new file mode 100644 index 000000000000..929d017535a3 --- /dev/null +++ b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c @@ -0,0 +1,560 @@ +/* + * LocalPlus Bus FIFO driver for the Freescale MPC52xx. + * + * Copyright (C) 2009 Secret Lab Technologies Ltd. + * + * This file is released under the GPLv2 + * + * Todo: + * - Add support for multiple requests to be queued. + */ + +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/spinlock.h> +#include <asm/io.h> +#include <asm/prom.h> +#include <asm/mpc52xx.h> +#include <asm/time.h> + +#include <sysdev/bestcomm/bestcomm.h> +#include <sysdev/bestcomm/bestcomm_priv.h> +#include <sysdev/bestcomm/gen_bd.h> + +MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>"); +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 transfered + */ +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 */ + 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 becuase everyting 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 transfered + * 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 = get_tbl(); + + 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 writting)\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 += get_tbl() - 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 = get_tbl(); + + 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 += get_tbl() - 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); + +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 __devinit +mpc52xx_lpbfifo_probe(struct of_device *op, const struct of_device_id *match) +{ + struct resource res; + int rc = -ENOMEM; + + if (lpbfifo.dev != NULL) + return -ENOSPC; + + lpbfifo.irq = irq_of_parse_and_map(op->node, 0); + if (!lpbfifo.irq) + return -ENODEV; + + if (of_address_to_resource(op->node, 0, &res)) + return -ENODEV; + lpbfifo.regs_phys = res.start; + lpbfifo.regs = of_iomap(op->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; + + /* 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: + err_irq: + iounmap(lpbfifo.regs); + lpbfifo.regs = NULL; + + dev_err(&op->dev, "mpc52xx_lpbfifo_probe() failed\n"); + return -ENODEV; +} + + +static int __devexit mpc52xx_lpbfifo_remove(struct of_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 struct of_device_id mpc52xx_lpbfifo_match[] __devinitconst = { + { .compatible = "fsl,mpc5200-lpbfifo", }, + {}, +}; + +static struct of_platform_driver mpc52xx_lpbfifo_driver = { + .owner = THIS_MODULE, + .name = "mpc52xx-lpbfifo", + .match_table = mpc52xx_lpbfifo_match, + .probe = mpc52xx_lpbfifo_probe, + .remove = __devexit_p(mpc52xx_lpbfifo_remove), +}; + +/*********************************************************************** + * Module init/exit + */ +static int __init mpc52xx_lpbfifo_init(void) +{ + pr_debug("Registering LocalPlus bus FIFO driver\n"); + return of_register_platform_driver(&mpc52xx_lpbfifo_driver); +} +module_init(mpc52xx_lpbfifo_init); + +static void __exit mpc52xx_lpbfifo_exit(void) +{ + pr_debug("Unregistering LocalPlus bus FIFO driver\n"); + of_unregister_platform_driver(&mpc52xx_lpbfifo_driver); +} +module_exit(mpc52xx_lpbfifo_exit); |