diff options
Diffstat (limited to 'drivers/soc/apple/dockchannel.c')
| -rw-r--r-- | drivers/soc/apple/dockchannel.c | 407 |
1 files changed, 407 insertions, 0 deletions
diff --git a/drivers/soc/apple/dockchannel.c b/drivers/soc/apple/dockchannel.c new file mode 100644 index 000000000000..b4d793bf2102 --- /dev/null +++ b/drivers/soc/apple/dockchannel.c @@ -0,0 +1,407 @@ +// SPDX-License-Identifier: GPL-2.0-only OR MIT +/* + * Apple DockChannel FIFO driver + * Copyright The Asahi Linux Contributors + */ + +#include <asm/unaligned.h> +#include <linux/device.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/ioport.h> +#include <linux/irq.h> +#include <linux/irqchip/chained_irq.h> +#include <linux/irqdomain.h> +#include <linux/soc/apple/dockchannel.h> +#include <linux/of.h> +#include <linux/of_platform.h> + +#define DOCKCHANNEL_MAX_IRQ 32 + +#define DOCKCHANNEL_TX_TIMEOUT_MS 1000 +#define DOCKCHANNEL_RX_TIMEOUT_MS 1000 + +#define IRQ_MASK 0x0 +#define IRQ_FLAG 0x4 + +#define IRQ_TX BIT(0) +#define IRQ_RX BIT(1) + +#define CONFIG_TX_THRESH 0x0 +#define CONFIG_RX_THRESH 0x4 + +#define DATA_TX8 0x4 +#define DATA_TX16 0x8 +#define DATA_TX24 0xc +#define DATA_TX32 0x10 +#define DATA_TX_FREE 0x14 +#define DATA_RX8 0x1c +#define DATA_RX16 0x20 +#define DATA_RX24 0x24 +#define DATA_RX32 0x28 +#define DATA_RX_COUNT 0x2c + +struct dockchannel { + struct device *dev; + int tx_irq; + int rx_irq; + + void __iomem *config_base; + void __iomem *data_base; + + u32 fifo_size; + bool awaiting; + struct completion tx_comp; + struct completion rx_comp; + + void *cookie; + void (*data_available)(void *cookie, size_t avail); +}; + +struct dockchannel_common { + struct device *dev; + struct irq_domain *domain; + int irq; + + void __iomem *irq_base; +}; + +/* Dockchannel FIFO functions */ + +static irqreturn_t dockchannel_tx_irq(int irq, void *data) +{ + struct dockchannel *dockchannel = data; + + disable_irq_nosync(irq); + complete(&dockchannel->tx_comp); + + return IRQ_HANDLED; +} + +static irqreturn_t dockchannel_rx_irq(int irq, void *data) +{ + struct dockchannel *dockchannel = data; + + disable_irq_nosync(irq); + + if (dockchannel->awaiting) { + return IRQ_WAKE_THREAD; + } else { + complete(&dockchannel->rx_comp); + return IRQ_HANDLED; + } +} + +static irqreturn_t dockchannel_rx_irq_thread(int irq, void *data) +{ + struct dockchannel *dockchannel = data; + size_t avail = readl_relaxed(dockchannel->data_base + DATA_RX_COUNT); + + dockchannel->awaiting = false; + dockchannel->data_available(dockchannel->cookie, avail); + + return IRQ_HANDLED; +} + +int dockchannel_send(struct dockchannel *dockchannel, const void *buf, size_t count) +{ + size_t left = count; + const u8 *p = buf; + + while (left > 0) { + size_t avail = readl_relaxed(dockchannel->data_base + DATA_TX_FREE); + size_t block = min(left, avail); + + if (avail == 0) { + size_t threshold = min((size_t)(dockchannel->fifo_size / 2), left); + + writel_relaxed(threshold, dockchannel->config_base + CONFIG_TX_THRESH); + reinit_completion(&dockchannel->tx_comp); + enable_irq(dockchannel->tx_irq); + + if (!wait_for_completion_timeout(&dockchannel->tx_comp, + msecs_to_jiffies(DOCKCHANNEL_TX_TIMEOUT_MS))) { + disable_irq(dockchannel->tx_irq); + return -ETIMEDOUT; + } + + continue; + } + + while (block >= 4) { + writel_relaxed(get_unaligned_le32(p), dockchannel->data_base + DATA_TX32); + p += 4; + left -= 4; + block -= 4; + } + while (block > 0) { + writeb_relaxed(*p++, dockchannel->data_base + DATA_TX8); + left--; + block--; + } + } + + return count; +} +EXPORT_SYMBOL(dockchannel_send); + +int dockchannel_recv(struct dockchannel *dockchannel, void *buf, size_t count) +{ + size_t left = count; + u8 *p = buf; + + while (left > 0) { + size_t avail = readl_relaxed(dockchannel->data_base + DATA_RX_COUNT); + size_t block = min(left, avail); + + if (avail == 0) { + size_t threshold = min((size_t)(dockchannel->fifo_size / 2), left); + + writel_relaxed(threshold, dockchannel->config_base + CONFIG_RX_THRESH); + reinit_completion(&dockchannel->rx_comp); + enable_irq(dockchannel->rx_irq); + + if (!wait_for_completion_timeout(&dockchannel->rx_comp, + msecs_to_jiffies(DOCKCHANNEL_RX_TIMEOUT_MS))) { + disable_irq(dockchannel->rx_irq); + return -ETIMEDOUT; + } + + continue; + } + + while (block >= 4) { + put_unaligned_le32(readl_relaxed(dockchannel->data_base + DATA_RX32), p); + p += 4; + left -= 4; + block -= 4; + } + while (block > 0) { + *p++ = readl_relaxed(dockchannel->data_base + DATA_RX8) >> 8; + left--; + block--; + } + } + + return count; +} +EXPORT_SYMBOL(dockchannel_recv); + +int dockchannel_await(struct dockchannel *dockchannel, + void (*callback)(void *cookie, size_t avail), + void *cookie, size_t count) +{ + size_t threshold = min((size_t)dockchannel->fifo_size, count); + + if (!count) { + dockchannel->awaiting = false; + disable_irq(dockchannel->rx_irq); + return 0; + } + + dockchannel->data_available = callback; + dockchannel->cookie = cookie; + dockchannel->awaiting = true; + writel_relaxed(threshold, dockchannel->config_base + CONFIG_RX_THRESH); + enable_irq(dockchannel->rx_irq); + + return threshold; +} +EXPORT_SYMBOL(dockchannel_await); + +struct dockchannel *dockchannel_init(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct dockchannel *dockchannel; + int ret; + + dockchannel = devm_kzalloc(dev, sizeof(*dockchannel), GFP_KERNEL); + if (!dockchannel) + return ERR_PTR(-ENOMEM); + + dockchannel->dev = dev; + dockchannel->config_base = devm_platform_ioremap_resource_byname(pdev, "config"); + if (IS_ERR(dockchannel->config_base)) + return (__force void *)dockchannel->config_base; + + dockchannel->data_base = devm_platform_ioremap_resource_byname(pdev, "data"); + if (IS_ERR(dockchannel->data_base)) + return (__force void *)dockchannel->data_base; + + ret = of_property_read_u32(dev->of_node, "apple,fifo-size", &dockchannel->fifo_size); + if (ret) + return ERR_PTR(dev_err_probe(dev, ret, "Missing apple,fifo-size property")); + + init_completion(&dockchannel->tx_comp); + init_completion(&dockchannel->rx_comp); + + dockchannel->tx_irq = platform_get_irq_byname(pdev, "tx"); + if (dockchannel->tx_irq <= 0) { + return ERR_PTR(dev_err_probe(dev, dockchannel->tx_irq, + "Failed to get TX IRQ")); + } + + dockchannel->rx_irq = platform_get_irq_byname(pdev, "rx"); + if (dockchannel->rx_irq <= 0) { + return ERR_PTR(dev_err_probe(dev, dockchannel->rx_irq, + "Failed to get RX IRQ")); + } + + ret = devm_request_irq(dev, dockchannel->tx_irq, dockchannel_tx_irq, IRQF_NO_AUTOEN, + "apple-dockchannel-tx", dockchannel); + if (ret) + return ERR_PTR(dev_err_probe(dev, ret, "Failed to request TX IRQ")); + + ret = devm_request_threaded_irq(dev, dockchannel->rx_irq, dockchannel_rx_irq, + dockchannel_rx_irq_thread, IRQF_NO_AUTOEN, + "apple-dockchannel-rx", dockchannel); + if (ret) + return ERR_PTR(dev_err_probe(dev, ret, "Failed to request RX IRQ")); + + return dockchannel; +} +EXPORT_SYMBOL(dockchannel_init); + + +/* Dockchannel IRQchip */ + +static void dockchannel_irq(struct irq_desc *desc) +{ + unsigned int irq = irq_desc_get_irq(desc); + struct irq_chip *chip = irq_desc_get_chip(desc); + struct dockchannel_common *dcc = irq_get_handler_data(irq); + unsigned long flags = readl_relaxed(dcc->irq_base + IRQ_FLAG); + int bit; + + chained_irq_enter(chip, desc); + + for_each_set_bit(bit, &flags, DOCKCHANNEL_MAX_IRQ) + generic_handle_domain_irq(dcc->domain, bit); + + chained_irq_exit(chip, desc); +} + +static void dockchannel_irq_ack(struct irq_data *data) +{ + struct dockchannel_common *dcc = irq_data_get_irq_chip_data(data); + unsigned int hwirq = data->hwirq; + + writel_relaxed(BIT(hwirq), dcc->irq_base + IRQ_FLAG); +} + +static void dockchannel_irq_mask(struct irq_data *data) +{ + struct dockchannel_common *dcc = irq_data_get_irq_chip_data(data); + unsigned int hwirq = data->hwirq; + u32 val = readl_relaxed(dcc->irq_base + IRQ_MASK); + + writel_relaxed(val & ~BIT(hwirq), dcc->irq_base + IRQ_MASK); +} + +static void dockchannel_irq_unmask(struct irq_data *data) +{ + struct dockchannel_common *dcc = irq_data_get_irq_chip_data(data); + unsigned int hwirq = data->hwirq; + u32 val = readl_relaxed(dcc->irq_base + IRQ_MASK); + + writel_relaxed(val | BIT(hwirq), dcc->irq_base + IRQ_MASK); +} + +static const struct irq_chip dockchannel_irqchip = { + .name = "dockchannel-irqc", + .irq_ack = dockchannel_irq_ack, + .irq_mask = dockchannel_irq_mask, + .irq_unmask = dockchannel_irq_unmask, +}; + +static int dockchannel_irq_domain_map(struct irq_domain *d, unsigned int virq, + irq_hw_number_t hw) +{ + irq_set_chip_data(virq, d->host_data); + irq_set_chip_and_handler(virq, &dockchannel_irqchip, handle_level_irq); + + return 0; +} + +static const struct irq_domain_ops dockchannel_irq_domain_ops = { + .xlate = irq_domain_xlate_twocell, + .map = dockchannel_irq_domain_map, +}; + +static int dockchannel_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct dockchannel_common *dcc; + struct device_node *child; + + dcc = devm_kzalloc(dev, sizeof(*dcc), GFP_KERNEL); + if (!dcc) + return -ENOMEM; + + dcc->dev = dev; + platform_set_drvdata(pdev, dcc); + + dcc->irq_base = devm_platform_ioremap_resource_byname(pdev, "irq"); + if (IS_ERR(dcc->irq_base)) + return PTR_ERR(dcc->irq_base); + + writel_relaxed(0, dcc->irq_base + IRQ_MASK); + writel_relaxed(~0, dcc->irq_base + IRQ_FLAG); + + dcc->domain = irq_domain_add_linear(dev->of_node, DOCKCHANNEL_MAX_IRQ, + &dockchannel_irq_domain_ops, dcc); + if (!dcc->domain) + return -ENOMEM; + + dcc->irq = platform_get_irq(pdev, 0); + if (dcc->irq <= 0) + return dev_err_probe(dev, dcc->irq, "Failed to get IRQ"); + + irq_set_handler_data(dcc->irq, dcc); + irq_set_chained_handler(dcc->irq, dockchannel_irq); + + for_each_child_of_node(dev->of_node, child) + of_platform_device_create(child, NULL, dev); + + return 0; +} + +static int dockchannel_remove(struct platform_device *pdev) +{ + struct dockchannel_common *dcc = platform_get_drvdata(pdev); + int hwirq; + + device_for_each_child(&pdev->dev, NULL, of_platform_device_destroy); + + irq_set_chained_handler_and_data(dcc->irq, NULL, NULL); + + for (hwirq = 0; hwirq < DOCKCHANNEL_MAX_IRQ; hwirq++) + irq_dispose_mapping(irq_find_mapping(dcc->domain, hwirq)); + + irq_domain_remove(dcc->domain); + + writel_relaxed(0, dcc->irq_base + IRQ_MASK); + writel_relaxed(~0, dcc->irq_base + IRQ_FLAG); + + return 0; +} + +static const struct of_device_id dockchannel_of_match[] = { + { .compatible = "apple,dockchannel" }, + {}, +}; +MODULE_DEVICE_TABLE(of, dockchannel_of_match); + +static struct platform_driver dockchannel_driver = { + .driver = { + .name = "dockchannel", + .of_match_table = dockchannel_of_match, + }, + .probe = dockchannel_probe, + .remove = dockchannel_remove, +}; +module_platform_driver(dockchannel_driver); + +MODULE_AUTHOR("Hector Martin <marcan@marcan.st>"); +MODULE_LICENSE("Dual MIT/GPL"); +MODULE_DESCRIPTION("Apple DockChannel driver"); |