60 lines
2.3 KiB
Diff
60 lines
2.3 KiB
Diff
From 64ad46379fcf14f437553f654d1adcd3d0e0d7f9 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Mon, 15 Aug 2016 14:21:28 +0200
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Subject: [PATCH] mtd: bcm47xxsflash: use uncached MMIO access for BCM53573
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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BCM53573 is a new series of Broadcom's SoCs. It's based on ARM and uses
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this old ChipCommon-based flash access. Early tests resulted in flash
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corruptions that were tracked down to using cached MMIO for flash read
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access. Switch to ioremap_nocache conditionally to support BCM53573 and
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don't break performance on old MIPS devices.
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
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Signed-off-by: Brian Norris <computersforpeace@gmail.com>
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---
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drivers/mtd/devices/bcm47xxsflash.c | 24 +++++++++++++++++++-----
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1 file changed, 19 insertions(+), 5 deletions(-)
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--- a/drivers/mtd/devices/bcm47xxsflash.c
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+++ b/drivers/mtd/devices/bcm47xxsflash.c
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@@ -296,16 +296,30 @@ static int bcm47xxsflash_bcma_probe(stru
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dev_err(dev, "can't request region for resource %pR\n", res);
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return -EBUSY;
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}
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- b47s->window = ioremap_cache(res->start, resource_size(res));
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- if (!b47s->window) {
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- dev_err(dev, "ioremap failed for resource %pR\n", res);
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- return -ENOMEM;
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- }
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b47s->bcma_cc = container_of(sflash, struct bcma_drv_cc, sflash);
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b47s->cc_read = bcm47xxsflash_bcma_cc_read;
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b47s->cc_write = bcm47xxsflash_bcma_cc_write;
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+ /*
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+ * On old MIPS devices cache was magically invalidated when needed,
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+ * allowing us to use cached access and gain some performance. Trying
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+ * the same on ARM based BCM53573 results in flash corruptions, we need
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+ * to use uncached access for it.
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+ *
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+ * It may be arch specific, but right now there is only 1 ARM SoC using
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+ * this driver, so let's follow Broadcom's reference code and check
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+ * ChipCommon revision.
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+ */
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+ if (b47s->bcma_cc->core->id.rev == 54)
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+ b47s->window = ioremap_nocache(res->start, resource_size(res));
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+ else
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+ b47s->window = ioremap_cache(res->start, resource_size(res));
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+ if (!b47s->window) {
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+ dev_err(dev, "ioremap failed for resource %pR\n", res);
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+ return -ENOMEM;
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+ }
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+
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switch (b47s->bcma_cc->capabilities & BCMA_CC_CAP_FLASHT) {
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case BCMA_CC_FLASHT_STSER:
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b47s->type = BCM47XXSFLASH_TYPE_ST;
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