340 lines
8.2 KiB
C
340 lines
8.2 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2018-2020 Broadcom.
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*/
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#include <linux/tty.h>
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#include <linux/tty_driver.h>
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#include <linux/tty_flip.h>
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#include "bcm_vk.h"
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/* TTYVK base offset is 0x30000 into BAR1 */
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#define BAR1_TTYVK_BASE_OFFSET 0x300000
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/* Each TTYVK channel (TO or FROM) is 0x10000 */
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#define BAR1_TTYVK_CHAN_OFFSET 0x100000
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/* Each TTYVK channel has TO and FROM, hence the * 2 */
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#define BAR1_TTYVK_BASE(index) (BAR1_TTYVK_BASE_OFFSET + \
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((index) * BAR1_TTYVK_CHAN_OFFSET * 2))
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/* TO TTYVK channel base comes before FROM for each index */
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#define TO_TTYK_BASE(index) BAR1_TTYVK_BASE(index)
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#define FROM_TTYK_BASE(index) (BAR1_TTYVK_BASE(index) + \
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BAR1_TTYVK_CHAN_OFFSET)
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struct bcm_vk_tty_chan {
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u32 reserved;
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u32 size;
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u32 wr;
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u32 rd;
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u32 *data;
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};
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#define VK_BAR_CHAN(v, DIR, e) ((v)->DIR##_offset \
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+ offsetof(struct bcm_vk_tty_chan, e))
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#define VK_BAR_CHAN_SIZE(v, DIR) VK_BAR_CHAN(v, DIR, size)
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#define VK_BAR_CHAN_WR(v, DIR) VK_BAR_CHAN(v, DIR, wr)
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#define VK_BAR_CHAN_RD(v, DIR) VK_BAR_CHAN(v, DIR, rd)
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#define VK_BAR_CHAN_DATA(v, DIR, off) (VK_BAR_CHAN(v, DIR, data) + (off))
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#define VK_BAR0_REGSEG_TTY_DB_OFFSET 0x86c
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/* Poll every 1/10 of second - temp hack till we use MSI interrupt */
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#define SERIAL_TIMER_VALUE (HZ / 10)
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static void bcm_vk_tty_poll(struct timer_list *t)
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{
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struct bcm_vk *vk = from_timer(vk, t, serial_timer);
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queue_work(vk->tty_wq_thread, &vk->tty_wq_work);
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mod_timer(&vk->serial_timer, jiffies + SERIAL_TIMER_VALUE);
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}
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irqreturn_t bcm_vk_tty_irqhandler(int irq, void *dev_id)
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{
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struct bcm_vk *vk = dev_id;
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queue_work(vk->tty_wq_thread, &vk->tty_wq_work);
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return IRQ_HANDLED;
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}
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static void bcm_vk_tty_wq_handler(struct work_struct *work)
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{
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struct bcm_vk *vk = container_of(work, struct bcm_vk, tty_wq_work);
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struct bcm_vk_tty *vktty;
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int card_status;
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int count;
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unsigned char c;
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int i;
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int wr;
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card_status = vkread32(vk, BAR_0, BAR_CARD_STATUS);
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if (BCM_VK_INTF_IS_DOWN(card_status))
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return;
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for (i = 0; i < BCM_VK_NUM_TTY; i++) {
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count = 0;
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/* Check the card status that the tty channel is ready */
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if ((card_status & BIT(i)) == 0)
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continue;
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vktty = &vk->tty[i];
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/* Don't increment read index if tty app is closed */
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if (!vktty->is_opened)
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continue;
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/* Fetch the wr offset in buffer from VK */
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wr = vkread32(vk, BAR_1, VK_BAR_CHAN_WR(vktty, from));
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/* safe to ignore until bar read gives proper size */
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if (vktty->from_size == 0)
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continue;
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if (wr >= vktty->from_size) {
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dev_err(&vk->pdev->dev,
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"ERROR: wq handler ttyVK%d wr:0x%x > 0x%x\n",
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i, wr, vktty->from_size);
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/* Need to signal and close device in this case */
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continue;
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}
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/*
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* Simple read of circular buffer and
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* insert into tty flip buffer
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*/
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while (vk->tty[i].rd != wr) {
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c = vkread8(vk, BAR_1,
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VK_BAR_CHAN_DATA(vktty, from, vktty->rd));
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vktty->rd++;
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if (vktty->rd >= vktty->from_size)
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vktty->rd = 0;
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tty_insert_flip_char(&vktty->port, c, TTY_NORMAL);
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count++;
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}
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if (count) {
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tty_flip_buffer_push(&vktty->port);
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/* Update read offset from shadow register to card */
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vkwrite32(vk, vktty->rd, BAR_1,
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VK_BAR_CHAN_RD(vktty, from));
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}
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}
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}
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static int bcm_vk_tty_open(struct tty_struct *tty, struct file *file)
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{
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int card_status;
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struct bcm_vk *vk;
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struct bcm_vk_tty *vktty;
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int index;
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/* initialize the pointer in case something fails */
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tty->driver_data = NULL;
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vk = (struct bcm_vk *)dev_get_drvdata(tty->dev);
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index = tty->index;
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if (index >= BCM_VK_NUM_TTY)
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return -EINVAL;
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vktty = &vk->tty[index];
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vktty->pid = task_pid_nr(current);
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vktty->to_offset = TO_TTYK_BASE(index);
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vktty->from_offset = FROM_TTYK_BASE(index);
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/* Do not allow tty device to be opened if tty on card not ready */
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card_status = vkread32(vk, BAR_0, BAR_CARD_STATUS);
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if (BCM_VK_INTF_IS_DOWN(card_status) || ((card_status & BIT(index)) == 0))
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return -EBUSY;
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/*
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* Get shadow registers of the buffer sizes and the "to" write offset
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* and "from" read offset
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*/
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vktty->to_size = vkread32(vk, BAR_1, VK_BAR_CHAN_SIZE(vktty, to));
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vktty->wr = vkread32(vk, BAR_1, VK_BAR_CHAN_WR(vktty, to));
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vktty->from_size = vkread32(vk, BAR_1, VK_BAR_CHAN_SIZE(vktty, from));
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vktty->rd = vkread32(vk, BAR_1, VK_BAR_CHAN_RD(vktty, from));
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vktty->is_opened = true;
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if (tty->count == 1 && !vktty->irq_enabled) {
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timer_setup(&vk->serial_timer, bcm_vk_tty_poll, 0);
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mod_timer(&vk->serial_timer, jiffies + SERIAL_TIMER_VALUE);
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}
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return 0;
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}
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static void bcm_vk_tty_close(struct tty_struct *tty, struct file *file)
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{
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struct bcm_vk *vk = dev_get_drvdata(tty->dev);
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if (tty->index >= BCM_VK_NUM_TTY)
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return;
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vk->tty[tty->index].is_opened = false;
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if (tty->count == 1)
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del_timer_sync(&vk->serial_timer);
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}
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static void bcm_vk_tty_doorbell(struct bcm_vk *vk, u32 db_val)
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{
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vkwrite32(vk, db_val, BAR_0,
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VK_BAR0_REGSEG_DB_BASE + VK_BAR0_REGSEG_TTY_DB_OFFSET);
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}
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static int bcm_vk_tty_write(struct tty_struct *tty,
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const unsigned char *buffer,
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int count)
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{
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int index;
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struct bcm_vk *vk;
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struct bcm_vk_tty *vktty;
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int i;
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index = tty->index;
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vk = dev_get_drvdata(tty->dev);
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vktty = &vk->tty[index];
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/* Simple write each byte to circular buffer */
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for (i = 0; i < count; i++) {
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vkwrite8(vk, buffer[i], BAR_1,
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VK_BAR_CHAN_DATA(vktty, to, vktty->wr));
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vktty->wr++;
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if (vktty->wr >= vktty->to_size)
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vktty->wr = 0;
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}
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/* Update write offset from shadow register to card */
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vkwrite32(vk, vktty->wr, BAR_1, VK_BAR_CHAN_WR(vktty, to));
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bcm_vk_tty_doorbell(vk, 0);
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return count;
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}
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static unsigned int bcm_vk_tty_write_room(struct tty_struct *tty)
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{
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struct bcm_vk *vk = dev_get_drvdata(tty->dev);
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return vk->tty[tty->index].to_size - 1;
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}
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static const struct tty_operations serial_ops = {
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.open = bcm_vk_tty_open,
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.close = bcm_vk_tty_close,
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.write = bcm_vk_tty_write,
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.write_room = bcm_vk_tty_write_room,
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};
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int bcm_vk_tty_init(struct bcm_vk *vk, char *name)
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{
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int i;
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int err;
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struct tty_driver *tty_drv;
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struct device *dev = &vk->pdev->dev;
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tty_drv = tty_alloc_driver
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(BCM_VK_NUM_TTY,
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TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV);
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if (IS_ERR(tty_drv))
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return PTR_ERR(tty_drv);
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/* Save struct tty_driver for uninstalling the device */
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vk->tty_drv = tty_drv;
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/* initialize the tty driver */
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tty_drv->driver_name = KBUILD_MODNAME;
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tty_drv->name = kstrdup(name, GFP_KERNEL);
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if (!tty_drv->name) {
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err = -ENOMEM;
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goto err_tty_driver_kref_put;
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}
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tty_drv->type = TTY_DRIVER_TYPE_SERIAL;
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tty_drv->subtype = SERIAL_TYPE_NORMAL;
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tty_drv->init_termios = tty_std_termios;
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tty_set_operations(tty_drv, &serial_ops);
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/* register the tty driver */
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err = tty_register_driver(tty_drv);
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if (err) {
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dev_err(dev, "tty_register_driver failed\n");
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goto err_kfree_tty_name;
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}
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for (i = 0; i < BCM_VK_NUM_TTY; i++) {
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struct device *tty_dev;
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tty_port_init(&vk->tty[i].port);
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tty_dev = tty_port_register_device_attr(&vk->tty[i].port,
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tty_drv, i, dev, vk,
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NULL);
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if (IS_ERR(tty_dev)) {
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err = PTR_ERR(tty_dev);
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goto unwind;
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}
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vk->tty[i].is_opened = false;
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}
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INIT_WORK(&vk->tty_wq_work, bcm_vk_tty_wq_handler);
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vk->tty_wq_thread = create_singlethread_workqueue("tty");
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if (!vk->tty_wq_thread) {
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dev_err(dev, "Fail to create tty workqueue thread\n");
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err = -ENOMEM;
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goto unwind;
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}
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return 0;
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unwind:
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while (--i >= 0)
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tty_port_unregister_device(&vk->tty[i].port, tty_drv, i);
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tty_unregister_driver(tty_drv);
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err_kfree_tty_name:
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kfree(tty_drv->name);
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tty_drv->name = NULL;
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err_tty_driver_kref_put:
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tty_driver_kref_put(tty_drv);
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return err;
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}
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void bcm_vk_tty_exit(struct bcm_vk *vk)
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{
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int i;
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del_timer_sync(&vk->serial_timer);
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for (i = 0; i < BCM_VK_NUM_TTY; ++i) {
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tty_port_unregister_device(&vk->tty[i].port,
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vk->tty_drv,
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i);
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tty_port_destroy(&vk->tty[i].port);
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}
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tty_unregister_driver(vk->tty_drv);
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kfree(vk->tty_drv->name);
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vk->tty_drv->name = NULL;
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tty_driver_kref_put(vk->tty_drv);
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}
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void bcm_vk_tty_terminate_tty_user(struct bcm_vk *vk)
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{
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struct bcm_vk_tty *vktty;
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int i;
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for (i = 0; i < BCM_VK_NUM_TTY; ++i) {
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vktty = &vk->tty[i];
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if (vktty->pid)
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kill_pid(find_vpid(vktty->pid), SIGKILL, 1);
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}
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}
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void bcm_vk_tty_wq_exit(struct bcm_vk *vk)
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{
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cancel_work_sync(&vk->tty_wq_work);
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destroy_workqueue(vk->tty_wq_thread);
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}
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