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// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2023 Linaro Ltd. */
#include <linux/platform_device.h>
#include <linux/io.h>
#include "gsi.h"
#include "gsi_reg.h"
/* GSI EE registers as a group are shifted downward by a fixed constant amount
* for IPA versions 4.5 and beyond. This applies to all GSI registers we use
* *except* the ones that disable inter-EE interrupts for channels and event
* channels.
*
* The "raw" (not adjusted) GSI register range is mapped, and a pointer to
* the mapped range is held in gsi->virt_raw. The inter-EE interrupt
* registers are accessed using that pointer.
*
* Most registers are accessed using gsi->virt, which is a copy of the "raw"
* pointer, adjusted downward by the fixed amount.
*/
#define GSI_EE_REG_ADJUST 0x0000d000 /* IPA v4.5+ */
/* Sets gsi->virt_raw and gsi->virt, and I/O maps the "gsi" memory range */
int gsi_reg_init(struct gsi *gsi, struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct resource *res;
resource_size_t size;
u32 adjust;
/* Get GSI memory range and map it */
res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "gsi");
if (!res) {
dev_err(dev, "DT error getting \"gsi\" memory property\n");
return -ENODEV;
}
size = resource_size(res);
if (res->start > U32_MAX || size > U32_MAX - res->start) {
dev_err(dev, "DT memory resource \"gsi\" out of range\n");
return -EINVAL;
}
/* Make sure we can make our pointer adjustment if necessary */
adjust = gsi->version < IPA_VERSION_4_5 ? 0 : GSI_EE_REG_ADJUST;
if (res->start < adjust) {
dev_err(dev, "DT memory resource \"gsi\" too low (< %u)\n",
adjust);
return -EINVAL;
}
gsi->virt_raw = ioremap(res->start, size);
if (!gsi->virt_raw) {
dev_err(dev, "unable to remap \"gsi\" memory\n");
return -ENOMEM;
}
/* Most registers are accessed using an adjusted register range */
gsi->virt = gsi->virt_raw - adjust;
return 0;
}
/* Inverse of gsi_reg_init() */
void gsi_reg_exit(struct gsi *gsi)
{
gsi->virt = NULL;
iounmap(gsi->virt_raw);
gsi->virt_raw = NULL;
}
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