openwrt/target/linux/bcm27xx/patches-6.6/950-0835-mmc-sdhci-brcmstb-remove-32-bit-accessors-for-BCM271.patch

From d0f6e84d284870eda4a544002eb5ed0dce3d8680 Mon Sep 17 00:00:00 2001
From: Jonathan Bell <jonathan@raspberrypi.com>
Date: Mon, 8 Jan 2024 17:10:44 +0000
Subject: [PATCH 0835/1085] mmc: sdhci-brcmstb: remove 32-bit accessors for
 BCM2712

The reason for adding these are lost to the mists of time (and for a
previous chip revision). Removing these accessors appears to have no ill
effect on production chips, so get rid of the unnecessary RMW cycles.

Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
---
 drivers/mmc/host/Kconfig         |   1 -
 drivers/mmc/host/sdhci-brcmstb.c | 117 -------------------------------
 2 files changed, 118 deletions(-)

--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -1039,7 +1039,6 @@ config MMC_SDHCI_BRCMSTB
 	tristate "Broadcom SDIO/SD/MMC support"
 	depends on ARCH_BRCMSTB || BMIPS_GENERIC || COMPILE_TEST
 	depends on MMC_SDHCI_PLTFM
-	select MMC_SDHCI_IO_ACCESSORS
 	select MMC_CQHCI
 	select OF_DYNAMIC
 	default ARCH_BRCMSTB || BMIPS_GENERIC
--- a/drivers/mmc/host/sdhci-brcmstb.c
+++ b/drivers/mmc/host/sdhci-brcmstb.c
@@ -50,10 +50,6 @@ struct sdhci_brcmstb_priv {
 	unsigned int flags;
 	struct clk *base_clk;
 	u32 base_freq_hz;
-	u32 shadow_cmd;
-	u32 shadow_blk;
-	bool is_cmd_shadowed;
-	bool is_blk_shadowed;
 	struct regulator *sde_1v8;
 	struct device_node *sde_pcie;
 	void *__iomem sde_ioaddr;
@@ -122,113 +118,6 @@ static void sdhci_brcmstb_set_clock(stru
 	sdhci_enable_clk(host, clk);
 }
 
-#define REG_OFFSET_IN_BITS(reg) ((reg) << 3 & 0x18)
-
-static inline u32 sdhci_brcmstb_32only_readl(struct sdhci_host *host, int reg)
-{
-	u32 val = readl(host->ioaddr + reg);
-
-	pr_debug("%s: readl [0x%02x] 0x%08x\n",
-		 mmc_hostname(host->mmc), reg, val);
-	return val;
-}
-
-static u16 sdhci_brcmstb_32only_readw(struct sdhci_host *host, int reg)
-{
-	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
-	struct sdhci_brcmstb_priv *brcmstb_priv = sdhci_pltfm_priv(pltfm_host);
-	u32 val;
-	u16 word;
-
-	if ((reg == SDHCI_TRANSFER_MODE) && brcmstb_priv->is_cmd_shadowed) {
-		/* Get the saved transfer mode */
-		val = brcmstb_priv->shadow_cmd;
-	} else if ((reg == SDHCI_BLOCK_SIZE || reg == SDHCI_BLOCK_COUNT) &&
-		   brcmstb_priv->is_blk_shadowed) {
-		/* Get the saved block info */
-		val = brcmstb_priv->shadow_blk;
-	} else {
-		val = sdhci_brcmstb_32only_readl(host, (reg & ~3));
-	}
-	word = val >> REG_OFFSET_IN_BITS(reg) & 0xffff;
-	return word;
-}
-
-static u8 sdhci_brcmstb_32only_readb(struct sdhci_host *host, int reg)
-{
-	u32 val = sdhci_brcmstb_32only_readl(host, (reg & ~3));
-	u8 byte = val >> REG_OFFSET_IN_BITS(reg) & 0xff;
-	return byte;
-}
-
-static inline void sdhci_brcmstb_32only_writel(struct sdhci_host *host, u32 val, int reg)
-{
-	pr_debug("%s: writel [0x%02x] 0x%08x\n",
-		 mmc_hostname(host->mmc), reg, val);
-
-	writel(val, host->ioaddr + reg);
-}
-
-/*
- * BCM2712 unfortunately carries with it a perennial bug with the SD controller
- * register interface present on previous chips (2711/2709/2708). Accesses must
- * be dword-sized and a read-modify-write cycle to the 32-bit registers
- * containing the COMMAND, TRANSFER_MODE, BLOCK_SIZE and BLOCK_COUNT registers
- * tramples the upper/lower 16 bits of data written. BCM2712 does not seem to
- * need the extreme delay between each write as on previous chips, just the
- * serialisation of writes to these registers in a single 32-bit operation.
- */
-static void sdhci_brcmstb_32only_writew(struct sdhci_host *host, u16 val, int reg)
-{
-	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
-	struct sdhci_brcmstb_priv *brcmstb_priv = sdhci_pltfm_priv(pltfm_host);
-	u32 word_shift = REG_OFFSET_IN_BITS(reg);
-	u32 mask = 0xffff << word_shift;
-	u32 oldval, newval;
-
-	if (reg == SDHCI_COMMAND) {
-		/* Write the block now as we are issuing a command */
-		if (brcmstb_priv->is_blk_shadowed) {
-			sdhci_brcmstb_32only_writel(host, brcmstb_priv->shadow_blk,
-				SDHCI_BLOCK_SIZE);
-			brcmstb_priv->is_blk_shadowed = false;
-		}
-		oldval = brcmstb_priv->shadow_cmd;
-		brcmstb_priv->is_cmd_shadowed = false;
-	} else if ((reg == SDHCI_BLOCK_SIZE || reg == SDHCI_BLOCK_COUNT) &&
-		   brcmstb_priv->is_blk_shadowed) {
-		/* Block size and count are stored in shadow reg */
-		oldval = brcmstb_priv->shadow_blk;
-	} else {
-		/* Read reg, all other registers are not shadowed */
-		oldval = sdhci_brcmstb_32only_readl(host, (reg & ~3));
-	}
-	newval = (oldval & ~mask) | (val << word_shift);
-
-	if (reg == SDHCI_TRANSFER_MODE) {
-		/* Save the transfer mode until the command is issued */
-		brcmstb_priv->shadow_cmd = newval;
-		brcmstb_priv->is_cmd_shadowed = true;
-	} else if (reg == SDHCI_BLOCK_SIZE || reg == SDHCI_BLOCK_COUNT) {
-		/* Save the block info until the command is issued */
-		brcmstb_priv->shadow_blk = newval;
-		brcmstb_priv->is_blk_shadowed = true;
-	} else {
-		/* Command or other regular 32-bit write */
-		sdhci_brcmstb_32only_writel(host, newval, reg & ~3);
-	}
-}
-
-static void sdhci_brcmstb_32only_writeb(struct sdhci_host *host, u8 val, int reg)
-{
-	u32 oldval = sdhci_brcmstb_32only_readl(host, (reg & ~3));
-	u32 byte_shift = REG_OFFSET_IN_BITS(reg);
-	u32 mask = 0xff << byte_shift;
-	u32 newval = (oldval & ~mask) | (val << byte_shift);
-
-	sdhci_brcmstb_32only_writel(host, newval, reg & ~3);
-}
-
 static void sdhci_brcmstb_set_power(struct sdhci_host *host, unsigned char mode,
 				  unsigned short vdd)
 {
@@ -442,12 +331,6 @@ static struct sdhci_ops sdhci_brcmstb_op
 };
 
 static struct sdhci_ops sdhci_brcmstb_ops_2712 = {
-	.read_l = sdhci_brcmstb_32only_readl,
-	.read_w = sdhci_brcmstb_32only_readw,
-	.read_b = sdhci_brcmstb_32only_readb,
-	.write_l = sdhci_brcmstb_32only_writel,
-	.write_w = sdhci_brcmstb_32only_writew,
-	.write_b = sdhci_brcmstb_32only_writeb,
 	.set_clock = sdhci_set_clock,
 	.set_power = sdhci_brcmstb_set_power,
 	.set_bus_width = sdhci_set_bus_width,