Re: [PATCH v3 03/10] mtd: intel-dg: implement access functions

[Rodrigo Vivi]

On Tue, Nov 19, 2024 at 04:01:05PM +0200, Alexander Usyskin wrote:
> Implement read(), erase() and write() functions.
> 
> CC: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> CC: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> Acked-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> Co-developed-by: Tomas Winkler <tomasw@xxxxxxxxx>
> Signed-off-by: Tomas Winkler <tomasw@xxxxxxxxx>
> Co-developed-by: Vitaly Lubart <lubvital@xxxxxxxxx>
> Signed-off-by: Vitaly Lubart <lubvital@xxxxxxxxx>
> Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
> ---
>  drivers/mtd/devices/mtd-intel-dg.c | 197 +++++++++++++++++++++++++++++
>  1 file changed, 197 insertions(+)
> 
> diff --git a/drivers/mtd/devices/mtd-intel-dg.c b/drivers/mtd/devices/mtd-intel-dg.c
> index 05e333771be0..915b9750ca62 100644
> --- a/drivers/mtd/devices/mtd-intel-dg.c
> +++ b/drivers/mtd/devices/mtd-intel-dg.c
> @@ -5,13 +5,16 @@
>  
>  #include <linux/bitfield.h>
>  #include <linux/bits.h>
> +#include <linux/delay.h>
>  #include <linux/device.h>
>  #include <linux/intel_dg_nvm_aux.h>
>  #include <linux/io.h>
> +#include <linux/io-64-nonatomic-lo-hi.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/string.h>
>  #include <linux/slab.h>
> +#include <linux/sizes.h>
>  #include <linux/types.h>
>  
>  struct intel_dg_nvm {
> @@ -91,6 +94,33 @@ static inline u32 idg_nvm_read32(struct intel_dg_nvm *nvm, u32 address)
>  	return ioread32(base + NVM_TRIGGER_REG);
>  }
>  
> +static inline u64 idg_nvm_read64(struct intel_dg_nvm *nvm, u32 address)
> +{
> +	void __iomem *base = nvm->base;
> +
> +	iowrite32(address, base + NVM_ADDRESS_REG);
> +
> +	return readq(base + NVM_TRIGGER_REG);
> +}
> +
> +static void idg_nvm_write32(struct intel_dg_nvm *nvm, u32 address, u32 data)
> +{
> +	void __iomem *base = nvm->base;
> +
> +	iowrite32(address, base + NVM_ADDRESS_REG);
> +
> +	iowrite32(data, base + NVM_TRIGGER_REG);
> +}
> +
> +static void idg_nvm_write64(struct intel_dg_nvm *nvm, u32 address, u64 data)
> +{
> +	void __iomem *base = nvm->base;
> +
> +	iowrite32(address, base + NVM_ADDRESS_REG);
> +
> +	writeq(data, base + NVM_TRIGGER_REG);
> +}
> +
>  static int idg_nvm_get_access_map(struct intel_dg_nvm *nvm, u32 *access_map)
>  {
>  	u32 flmap1;
> @@ -147,6 +177,173 @@ static int idg_nvm_is_valid(struct intel_dg_nvm *nvm)
>  	return 0;
>  }
>  
> +__maybe_unused
> +static unsigned int idg_nvm_get_region(const struct intel_dg_nvm *nvm, loff_t from)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < nvm->nregions; i++) {
> +		if ((nvm->regions[i].offset + nvm->regions[i].size - 1) > from &&
> +		    nvm->regions[i].offset <= from &&
> +		    nvm->regions[i].size != 0)
> +			break;
> +	}
> +
> +	return i;
> +}
> +
> +static ssize_t idg_nvm_rewrite_partial(struct intel_dg_nvm *nvm, loff_t to,
> +				       loff_t offset, size_t len, const u32 *newdata)
> +{
> +	u32 data = idg_nvm_read32(nvm, to);
> +
> +	if (idg_nvm_error(nvm))
> +		return -EIO;
> +
> +	memcpy((u8 *)&data + offset, newdata, len);

I'm a bit concerned with the usage of len here without any check...

> +
> +	idg_nvm_write32(nvm, to, data);
> +	if (idg_nvm_error(nvm))
> +		return -EIO;
> +
> +	return len;
> +}
> +
> +__maybe_unused
> +static ssize_t idg_write(struct intel_dg_nvm *nvm, u8 region,
> +			 loff_t to, size_t len, const unsigned char *buf)
> +{
> +	size_t i;
> +	size_t len8;
> +	size_t len4;
> +	size_t to4;
> +	size_t to_shift;
> +	size_t len_s = len;
> +	ssize_t ret;
> +
> +	idg_nvm_set_region_id(nvm, region);
> +
> +	to4 = ALIGN_DOWN(to, sizeof(u32));
> +	to_shift = min(sizeof(u32) - ((size_t)to - to4), len);
> +	if (to - to4) {

As well the 'to'...

I was even trying to review all 3 patches together, 3, 4, and 5,
but there's too much indirection on those values and no checks
in any place...


> +		ret = idg_nvm_rewrite_partial(nvm, to4, to - to4, to_shift, (uint32_t *)&buf[0]);
> +		if (ret < 0)
> +			return ret;
> +
> +		buf += to_shift;
> +		to += to_shift;
> +		len_s -= to_shift;
> +	}
> +
> +	len8 = ALIGN_DOWN(len_s, sizeof(u64));
> +	for (i = 0; i < len8; i += sizeof(u64)) {
> +		u64 data;
> +
> +		memcpy(&data, &buf[i], sizeof(u64));
> +		idg_nvm_write64(nvm, to + i, data);
> +		if (idg_nvm_error(nvm))
> +			return -EIO;
> +	}
> +
> +	len4 = len_s - len8;
> +	if (len4 >= sizeof(u32)) {
> +		u32 data;
> +
> +		memcpy(&data, &buf[i], sizeof(u32));
> +		idg_nvm_write32(nvm, to + i, data);
> +		if (idg_nvm_error(nvm))
> +			return -EIO;
> +		i += sizeof(u32);
> +		len4 -= sizeof(u32);
> +	}
> +
> +	if (len4 > 0) {
> +		ret = idg_nvm_rewrite_partial(nvm, to + i, 0, len4, (uint32_t *)&buf[i]);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return len;
> +}
> +
> +__maybe_unused
> +static ssize_t idg_read(struct intel_dg_nvm *nvm, u8 region,
> +			loff_t from, size_t len, unsigned char *buf)
> +{
> +	size_t i;
> +	size_t len8;
> +	size_t len4;
> +	size_t from4;
> +	size_t from_shift;
> +	size_t len_s = len;
> +
> +	idg_nvm_set_region_id(nvm, region);
> +
> +	from4 = ALIGN_DOWN(from, sizeof(u32));
> +	from_shift = min(sizeof(u32) - ((size_t)from - from4), len);
> +
> +	if (from - from4) {
> +		u32 data = idg_nvm_read32(nvm, from4);
> +
> +		if (idg_nvm_error(nvm))
> +			return -EIO;
> +		memcpy(&buf[0], (u8 *)&data + (from - from4), from_shift);
> +		len_s -= from_shift;
> +		buf += from_shift;
> +		from += from_shift;
> +	}
> +
> +	len8 = ALIGN_DOWN(len_s, sizeof(u64));
> +	for (i = 0; i < len8; i += sizeof(u64)) {
> +		u64 data = idg_nvm_read64(nvm, from + i);
> +
> +		if (idg_nvm_error(nvm))
> +			return -EIO;
> +
> +		memcpy(&buf[i], &data, sizeof(data));
> +	}
> +
> +	len4 = len_s - len8;
> +	if (len4 >= sizeof(u32)) {
> +		u32 data = idg_nvm_read32(nvm, from + i);
> +
> +		if (idg_nvm_error(nvm))
> +			return -EIO;
> +		memcpy(&buf[i], &data, sizeof(data));
> +		i += sizeof(u32);
> +		len4 -= sizeof(u32);
> +	}
> +
> +	if (len4 > 0) {
> +		u32 data = idg_nvm_read32(nvm, from + i);
> +
> +		if (idg_nvm_error(nvm))
> +			return -EIO;
> +		memcpy(&buf[i], &data, len4);
> +	}
> +
> +	return len;
> +}
> +
> +__maybe_unused
> +static ssize_t
> +idg_erase(struct intel_dg_nvm *nvm, u8 region, loff_t from, u64 len, u64 *fail_addr)
> +{
> +	u64 i;
> +	const u32 block = 0x10;
> +	void __iomem *base = nvm->base;
> +
> +	for (i = 0; i < len; i += SZ_4K) {
> +		iowrite32(from + i, base + NVM_ADDRESS_REG);
> +		iowrite32(region << 24 | block, base + NVM_ERASE_REG);
> +		/* Since the writes are via sguint
> +		 * we cannot do back to back erases.
> +		 */
> +		msleep(50);
> +	}
> +	return len;
> +}
> +
>  static int intel_dg_nvm_init(struct intel_dg_nvm *nvm, struct device *device)
>  {
>  	int ret;
> -- 
> 2.43.0
>