Messages in this thread | | | Subject | Re: [RFC PATCH 2/2] soc: ti: Add Support for the TI Page-based Address Translator (PAT) | From | Tero Kristo <> | Date | Tue, 18 Jun 2019 12:07:58 +0300 |
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On 07/06/2019 22:35, Andrew F. Davis wrote: > This patch adds a driver for the Page-based Address Translator (PAT) > present on various TI SoCs. A PAT device performs address translation > using tables stored in an internal SRAM. Each PAT supports a set number > of pages, each occupying a programmable 4KB, 16KB, 64KB, or 1MB of > addresses in a window for which an incoming transaction will be > translated. > > Signed-off-by: Andrew F. Davis <afd@ti.com> > --- > drivers/soc/ti/Kconfig | 9 + > drivers/soc/ti/Makefile | 1 + > drivers/soc/ti/ti-pat.c | 569 ++++++++++++++++++++++++++++++++++++ > include/uapi/linux/ti-pat.h | 44 +++ > 4 files changed, 623 insertions(+) > create mode 100644 drivers/soc/ti/ti-pat.c > create mode 100644 include/uapi/linux/ti-pat.h > > diff --git a/drivers/soc/ti/Kconfig b/drivers/soc/ti/Kconfig > index f0be35d3dcba..b838ae74d01f 100644 > --- a/drivers/soc/ti/Kconfig > +++ b/drivers/soc/ti/Kconfig > @@ -86,4 +86,13 @@ config TI_SCI_INTA_MSI_DOMAIN > help > Driver to enable Interrupt Aggregator specific MSI Domain. > > +config TI_PAT > + tristate "TI PAT DMA-BUF exporter" > + select REGMAP
What is the reasoning for using regmap for internal register access? Why not just use direct readl/writel for everything? To me it seems this is only used during probe time also...
> + help > + Driver for TI Page-based Address Translator (PAT). This driver > + provides the an API allowing the remapping of a non-contiguous > + DMA-BUF into a contiguous one that is sutable for devices needing > + coniguous memory.
Minor typo: contiguous.
> + > endif # SOC_TI > diff --git a/drivers/soc/ti/Makefile b/drivers/soc/ti/Makefile > index b3868d392d4f..1369642b40c3 100644 > --- a/drivers/soc/ti/Makefile > +++ b/drivers/soc/ti/Makefile > @@ -9,3 +9,4 @@ obj-$(CONFIG_AMX3_PM) += pm33xx.o > obj-$(CONFIG_WKUP_M3_IPC) += wkup_m3_ipc.o > obj-$(CONFIG_TI_SCI_PM_DOMAINS) += ti_sci_pm_domains.o > obj-$(CONFIG_TI_SCI_INTA_MSI_DOMAIN) += ti_sci_inta_msi.o > +obj-$(CONFIG_TI_PAT) += ti-pat.o > diff --git a/drivers/soc/ti/ti-pat.c b/drivers/soc/ti/ti-pat.c > new file mode 100644 > index 000000000000..7359ea0f7ccf > --- /dev/null > +++ b/drivers/soc/ti/ti-pat.c > @@ -0,0 +1,569 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * TI PAT mapped DMA-BUF memory re-exporter > + * > + * Copyright (C) 2018-2019 Texas Instruments Incorporated - http://www.ti.com/ > + * Andrew F. Davis <afd@ti.com> > + */ > + > +#include <linux/fs.h> > +#include <linux/module.h> > +#include <linux/platform_device.h> > +#include <linux/mod_devicetable.h> > +#include <linux/uaccess.h> > +#include <linux/miscdevice.h> > +#include <linux/regmap.h> > +#include <linux/dma-buf.h> > +#include <linux/genalloc.h> > +#include <linux/vmalloc.h> > +#include <linux/slab.h> > + > +#include <linux/ti-pat.h> > + > +#define TI_PAT_DRIVER_NAME "ti-pat"
Why do you have a define for this seeing it is only used in single location?
> + > +/* TI PAT MMRS registers */ > +#define TI_PAT_MMRS_PID 0x0 /* Revision Register */ > +#define TI_PAT_MMRS_CONFIG 0x4 /* Config Register */ > +#define TI_PAT_MMRS_CONTROL 0x10 /* Control Register */ > + > +/* TI PAT CONTROL register field values */ > +#define TI_PAT_CONTROL_ARB_MODE_UF 0x0 /* Updates first */ > +#define TI_PAT_CONTROL_ARB_MODE_RR 0x2 /* Round-robin */ > + > +#define TI_PAT_CONTROL_PAGE_SIZE_4KB 0x0 > +#define TI_PAT_CONTROL_PAGE_SIZE_16KB 0x1 > +#define TI_PAT_CONTROL_PAGE_SIZE_64KB 0x2 > +#define TI_PAT_CONTROL_PAGE_SIZE_1MB 0x3 > + > +static unsigned int ti_pat_page_sizes[] = { > + [TI_PAT_CONTROL_PAGE_SIZE_4KB] = 4 * 1024, > + [TI_PAT_CONTROL_PAGE_SIZE_16KB] = 16 * 1024, > + [TI_PAT_CONTROL_PAGE_SIZE_64KB] = 64 * 1024, > + [TI_PAT_CONTROL_PAGE_SIZE_1MB] = 1024 * 1024, > +}; > + > +enum ti_pat_mmrs_fields { > + /* Revision */ > + F_PID_MAJOR, > + F_PID_MINOR, > + > + /* Controls */ > + F_CONTROL_ARB_MODE, > + F_CONTROL_PAGE_SIZE, > + F_CONTROL_REPLACE_OID_EN, > + F_CONTROL_EN, > + > + /* sentinel */ > + F_MAX_FIELDS > +}; > + > +static const struct reg_field ti_pat_mmrs_reg_fields[] = { > + /* Revision */ > + [F_PID_MAJOR] = REG_FIELD(TI_PAT_MMRS_PID, 8, 10), > + [F_PID_MINOR] = REG_FIELD(TI_PAT_MMRS_PID, 0, 5), > + /* Controls */ > + [F_CONTROL_ARB_MODE] = REG_FIELD(TI_PAT_MMRS_CONTROL, 6, 7), > + [F_CONTROL_PAGE_SIZE] = REG_FIELD(TI_PAT_MMRS_CONTROL, 4, 5), > + [F_CONTROL_REPLACE_OID_EN] = REG_FIELD(TI_PAT_MMRS_CONTROL, 1, 1), > + [F_CONTROL_EN] = REG_FIELD(TI_PAT_MMRS_CONTROL, 0, 0), > +}; > + > +/** > + * struct ti_pat_data - PAT device instance data > + * @dev: PAT device structure > + * @mdev: misc device > + * @mmrs_map: Register map of MMRS region > + * @table_base: Base address of TABLE region
Please add kerneldoc comments for all fields.
> + */ > +struct ti_pat_data { > + struct device *dev; > + struct miscdevice mdev; > + struct regmap *mmrs_map; > + struct regmap_field *mmrs_fields[F_MAX_FIELDS]; > + void __iomem *table_base; > + unsigned int page_count; > + unsigned int page_size; > + phys_addr_t window_base; > + struct gen_pool *pool; > +}; > +
Kerneldoc comments for below structs would be also useful, especially for ti_pat_buffer.
> +struct ti_pat_dma_buf_attachment { > + struct device *dev; > + struct sg_table *table; > + struct ti_pat_buffer *buffer; > + struct list_head list; > +}; > + > +struct ti_pat_buffer { > + struct ti_pat_data *pat; > + struct dma_buf *i_dma_buf; > + size_t size; > + unsigned long offset; > + struct dma_buf *e_dma_buf; > + > + struct dma_buf_attachment *attachment; > + struct sg_table *sgt; > + > + struct list_head attachments; > + int map_count; > + > + struct mutex lock; > +}; > + > +static const struct regmap_config ti_pat_regmap_config = { > + .reg_bits = 32, > + .val_bits = 32, > + .reg_stride = 4, > +}; > + > +static int ti_pat_dma_buf_attach(struct dma_buf *dmabuf, > + struct dma_buf_attachment *attachment) > +{ > + struct ti_pat_dma_buf_attachment *a; > + struct ti_pat_buffer *buffer = dmabuf->priv; > + > + a = kzalloc(sizeof(*a), GFP_KERNEL); > + if (!a) > + return -ENOMEM; > + > + a->dev = attachment->dev; > + a->buffer = buffer; > + INIT_LIST_HEAD(&a->list); > + > + a->table = kzalloc(sizeof(*a->table), GFP_KERNEL); > + if (!a->table) { > + kfree(a); > + return -ENOMEM; > + } > + > + if (sg_alloc_table(a->table, 1, GFP_KERNEL)) { > + kfree(a->table); > + kfree(a); > + return -ENOMEM; > + } > + > + sg_set_page(a->table->sgl, pfn_to_page(PFN_DOWN(buffer->offset)), buffer->size, 0); > + > + attachment->priv = a; > + > + mutex_lock(&buffer->lock); > + /* First time attachment we attach to parent */ > + if (list_empty(&buffer->attachments)) { > + buffer->attachment = dma_buf_attach(buffer->i_dma_buf, buffer->pat->dev); > + if (IS_ERR(buffer->attachment)) { > + dev_err(buffer->pat->dev, "Unable to attach to parent DMA-BUF\n"); > + mutex_unlock(&buffer->lock); > + kfree(a->table); > + kfree(a); > + return PTR_ERR(buffer->attachment); > + } > + } > + list_add(&a->list, &buffer->attachments); > + mutex_unlock(&buffer->lock); > + > + return 0; > +} > + > +static void ti_pat_dma_buf_detatch(struct dma_buf *dmabuf, > + struct dma_buf_attachment *attachment)
Func name should be ti_pat_dma_buf_detach instead?
Other than that, I can't see anything obvious with my limited experience with dma_buf. Is there a simple way to test this driver btw?
-Tero
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