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linux_dsm_epyc7002/arch/x86/pci/sta2x11-fixup.c
Nicolas Saenz Julienne a7ba70f178 dma-mapping: treat dev->bus_dma_mask as a DMA limit 
Using a mask to represent bus DMA constraints has a set of limitations.
The biggest one being it can only hold a power of two (minus one). The
DMA mapping code is already aware of this and treats dev->bus_dma_mask
as a limit. This quirk is already used by some architectures although
still rare.

With the introduction of the Raspberry Pi 4 we've found a new contender
for the use of bus DMA limits, as its PCIe bus can only address the
lower 3GB of memory (of a total of 4GB). This is impossible to represent
with a mask. To make things worse the device-tree code rounds non power
of two bus DMA limits to the next power of two, which is unacceptable in
this case.

In the light of this, rename dev->bus_dma_mask to dev->bus_dma_limit all
over the tree and treat it as such. Note that dev->bus_dma_limit should
contain the higher accessible DMA address.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-11-21 18:14:35 +01:00

232 lines
6.5 KiB
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// SPDX-License-Identifier: GPL-2.0-only
/*
* DMA translation between STA2x11 AMBA memory mapping and the x86 memory mapping
*
* ST Microelectronics ConneXt (STA2X11/STA2X10)
*
* Copyright (c) 2010-2011 Wind River Systems, Inc.
*/
#include <linux/pci.h>
#include <linux/pci_ids.h>
#include <linux/export.h>
#include <linux/list.h>
#include <linux/dma-direct.h>
#include <asm/iommu.h>
#define STA2X11_SWIOTLB_SIZE (4*1024*1024)
extern int swiotlb_late_init_with_default_size(size_t default_size);
/*
* We build a list of bus numbers that are under the ConneXt. The
* main bridge hosts 4 busses, which are the 4 endpoints, in order.
*/
#define STA2X11_NR_EP 4 /* 0..3 included */
#define STA2X11_NR_FUNCS 8 /* 0..7 included */
#define STA2X11_AMBA_SIZE (512 << 20)
struct sta2x11_ahb_regs { /* saved during suspend */
u32 base, pexlbase, pexhbase, crw;
};
struct sta2x11_mapping {
int is_suspended;
struct sta2x11_ahb_regs regs[STA2X11_NR_FUNCS];
};
struct sta2x11_instance {
struct list_head list;
int bus0;
struct sta2x11_mapping map[STA2X11_NR_EP];
};
static LIST_HEAD(sta2x11_instance_list);
/* At probe time, record new instances of this bridge (likely one only) */
static void sta2x11_new_instance(struct pci_dev *pdev)
{
struct sta2x11_instance *instance;
instance = kzalloc(sizeof(*instance), GFP_ATOMIC);
if (!instance)
return;
/* This has a subordinate bridge, with 4 more-subordinate ones */
instance->bus0 = pdev->subordinate->number + 1;
if (list_empty(&sta2x11_instance_list)) {
int size = STA2X11_SWIOTLB_SIZE;
/* First instance: register your own swiotlb area */
dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size);
if (swiotlb_late_init_with_default_size(size))
dev_emerg(&pdev->dev, "init swiotlb failed\n");
}
list_add(&instance->list, &sta2x11_instance_list);
}
DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, 0xcc17, sta2x11_new_instance);
/*
* Utility functions used in this file from below
*/
static struct sta2x11_instance *sta2x11_pdev_to_instance(struct pci_dev *pdev)
{
struct sta2x11_instance *instance;
int ep;
list_for_each_entry(instance, &sta2x11_instance_list, list) {
ep = pdev->bus->number - instance->bus0;
if (ep >= 0 && ep < STA2X11_NR_EP)
return instance;
}
return NULL;
}
static int sta2x11_pdev_to_ep(struct pci_dev *pdev)
{
struct sta2x11_instance *instance;
instance = sta2x11_pdev_to_instance(pdev);
if (!instance)
return -1;
return pdev->bus->number - instance->bus0;
}
/* This is exported, as some devices need to access the MFD registers */
struct sta2x11_instance *sta2x11_get_instance(struct pci_dev *pdev)
{
return sta2x11_pdev_to_instance(pdev);
}
EXPORT_SYMBOL(sta2x11_get_instance);
/* At setup time, we use our own ops if the device is a ConneXt one */
static void sta2x11_setup_pdev(struct pci_dev *pdev)
{
struct sta2x11_instance *instance = sta2x11_pdev_to_instance(pdev);
if (!instance) /* either a sta2x11 bridge or another ST device */
return;
/* We must enable all devices as master, for audio DMA to work */
pci_set_master(pdev);
}
DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, sta2x11_setup_pdev);
/*
* At boot we must set up the mappings for the pcie-to-amba bridge.
* It involves device access, and the same happens at suspend/resume time
*/
#define AHB_MAPB 0xCA4
#define AHB_CRW(i) (AHB_MAPB + 0 + (i) * 0x10)
#define AHB_CRW_SZMASK 0xfffffc00UL
#define AHB_CRW_ENABLE (1 << 0)
#define AHB_CRW_WTYPE_MEM (2 << 1)
#define AHB_CRW_ROE (1UL << 3) /* Relax Order Ena */
#define AHB_CRW_NSE (1UL << 4) /* No Snoop Enable */
#define AHB_BASE(i) (AHB_MAPB + 4 + (i) * 0x10)
#define AHB_PEXLBASE(i) (AHB_MAPB + 8 + (i) * 0x10)
#define AHB_PEXHBASE(i) (AHB_MAPB + 12 + (i) * 0x10)
/* At probe time, enable mapping for each endpoint, using the pdev */
static void sta2x11_map_ep(struct pci_dev *pdev)
{
struct sta2x11_instance *instance = sta2x11_pdev_to_instance(pdev);
struct device *dev = &pdev->dev;
u32 amba_base, max_amba_addr;
int i;
if (!instance)
return;
pci_read_config_dword(pdev, AHB_BASE(0), &amba_base);
max_amba_addr = amba_base + STA2X11_AMBA_SIZE - 1;
dev->dma_pfn_offset = PFN_DOWN(-amba_base);
dev->bus_dma_limit = max_amba_addr;
pci_set_consistent_dma_mask(pdev, max_amba_addr);
pci_set_dma_mask(pdev, max_amba_addr);
/* Configure AHB mapping */
pci_write_config_dword(pdev, AHB_PEXLBASE(0), 0);
pci_write_config_dword(pdev, AHB_PEXHBASE(0), 0);
pci_write_config_dword(pdev, AHB_CRW(0), STA2X11_AMBA_SIZE |
AHB_CRW_WTYPE_MEM | AHB_CRW_ENABLE);
/* Disable all the other windows */
for (i = 1; i < STA2X11_NR_FUNCS; i++)
pci_write_config_dword(pdev, AHB_CRW(i), 0);
dev_info(&pdev->dev,
"sta2x11: Map EP %i: AMBA address %#8x-%#8x\n",
sta2x11_pdev_to_ep(pdev), amba_base, max_amba_addr);
}
DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, sta2x11_map_ep);
#ifdef CONFIG_PM /* Some register values must be saved and restored */
static struct sta2x11_mapping *sta2x11_pdev_to_mapping(struct pci_dev *pdev)
{
struct sta2x11_instance *instance;
int ep;
instance = sta2x11_pdev_to_instance(pdev);
if (!instance)
return NULL;
ep = sta2x11_pdev_to_ep(pdev);
return instance->map + ep;
}
static void suspend_mapping(struct pci_dev *pdev)
{
struct sta2x11_mapping *map = sta2x11_pdev_to_mapping(pdev);
int i;
if (!map)
return;
if (map->is_suspended)
return;
map->is_suspended = 1;
/* Save all window configs */
for (i = 0; i < STA2X11_NR_FUNCS; i++) {
struct sta2x11_ahb_regs *regs = map->regs + i;
pci_read_config_dword(pdev, AHB_BASE(i), &regs->base);
pci_read_config_dword(pdev, AHB_PEXLBASE(i), &regs->pexlbase);
pci_read_config_dword(pdev, AHB_PEXHBASE(i), &regs->pexhbase);
pci_read_config_dword(pdev, AHB_CRW(i), &regs->crw);
}
}
DECLARE_PCI_FIXUP_SUSPEND(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, suspend_mapping);
static void resume_mapping(struct pci_dev *pdev)
{
struct sta2x11_mapping *map = sta2x11_pdev_to_mapping(pdev);
int i;
if (!map)
return;
if (!map->is_suspended)
goto out;
map->is_suspended = 0;
/* Restore all window configs */
for (i = 0; i < STA2X11_NR_FUNCS; i++) {
struct sta2x11_ahb_regs *regs = map->regs + i;
pci_write_config_dword(pdev, AHB_BASE(i), regs->base);
pci_write_config_dword(pdev, AHB_PEXLBASE(i), regs->pexlbase);
pci_write_config_dword(pdev, AHB_PEXHBASE(i), regs->pexhbase);
pci_write_config_dword(pdev, AHB_CRW(i), regs->crw);
}
out:
pci_set_master(pdev); /* Like at boot, enable master on all devices */
}
DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, resume_mapping);
#endif /* CONFIG_PM */
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